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Latest revision as of 08:38, 15 March 2020
| ML20023A760 | |
| Person / Time | |
|---|---|
| Site: | Skagit |
| Issue date: | 10/15/1982 |
| From: | Spangenberg F NORTHWEST ENERGY SERVICES CO. |
| To: | Adensam E Office of Nuclear Reactor Regulation |
| References | |
| NLN-33, NUDOCS 8210190729 | |
| Download: ML20023A760 (201) | |
Text
{{#Wiki_filter:1 NORTHWEST ENERGY SERWCES P. O. Box 1090 Kirkland Washington 98033 (206)828-7200 Telex:(206) 827-6230 October 15, 1982 NLN-33 Ms. E. Adensam, Chief Licensing Branch 4 Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Puget Sound Power & Light Company Skagit/Hanford Nuclear Project, Units 1 & 2 Docket Nos. 50-522 and 50-523 Preliminary Safety Analysis Report Draft Amendment 28
Dear Ms. Adensam:
At the direction of and with the concurrence of Puget Power, we are transmitting to you six copies of the Final Draft of Amendment 28 to the S/HNP PSAR. This action is being taken at this time so that an expeditious review of the material can commence and the SER finalized upon formal submittal in late October. Although some minor work remains on the draft, the technical material contain therein and conclusions reached will not change. This amendment consists of the responses to NRC Questions 231.5, 231.14 and 231.15; revisions to PSAR Section 2.5 and Appendices 2K and 2R incorporating recent work by the Supply System on the Southeast antic 11ne and by NESCO on the May Junction monocline. For the convenience of the reviewers, the current transmittal contains a complete copy of the relevant PSAR Sections 2.5.1 through 2.5.3 and Appendices 2K and 2R. The amended pages have been inserted into the above noted text and are marked " draft". " Change bars" in the right hand margin identify the location of the changes. The Final Draft has been printed on yellow pages so that it will be easily identified and not inadvsrtently inserted into the formal documentation. The following distribution of this Final Draft is suggested:
- 1. Mr. Moon, Project Manager
- 2. Dr. Jackson, Chief Geosciences Branch [Ac[5 *
- 3. Dr. Brocoum, Geosciences Branch C, Afssq i 4.
5. Mr. Lefevre, Geosciences Branch Dr. Ibrahim, Geosciences Branch l R.E. Tac dc'1.
- 6. Ms. Alterman, Geosciences Branch I 4 f, [fo c ount
- g. a d e D s+ l2- xba %
8210190729 8210 S J NNM. . l PDR ADOCK 05000522 pnR l R. Y L ! __
y -- Ms. Adensam October 15, 1982 Additional distribution of this Final Draft in the interest of time has also been made to the following reviewers in the U.S. Geological Survey.
- 1. Dr. Algermissen
- 2. Dr. Dickey
- 3. Dr. Morris If there are any questions regarding this transmittal, please call Mr. Stimac of Puget Power or myself immediately.
Very truly yours, f 4 .M . F. A. Sparkenbe n7 Project Manager ec: Dr. Slemmons M. V. Stimac - PSP &L Dr. Algermissen Dr. Dickey Dr. Morris l l l l l
. - . - . _ . . . - . . - , - . . . .i
10/14/82 S/HNP-PSAR affected the Site, the two highest intensities are estimated to have been IV-V (MM) from the December 14, 1872 earthquake and IV (MM) from the Milton-Freewater shock of July 15, 1936. The maximum acceleration at the Site resulting from historical or instrumental earthquanea is estimated to have been 0.015g (see Section 2.5.2.6 WNP-2 FSAR). A Regulatory Guide 1.60 Spectrum anchored at a peak h acceleration of 0.35g is assigned as the Safe Shutdown j Earthquake (SSE). The requirements of this SSE exceed those for all potential earthquakes discussed in Section 2.5.2.4. 1.2.2.1.2.7 Land use. Natural physical characteristics of the Plant Site, which indicate that the area is ideally situated for and suited for operation of the Plant, include: favorable geographical, geological, and seismological characteristics; adequate water supply; ideal climatological characteristics; and remoteness from population centers or areas of special ecological concern. The Hanford Reserva-tion has served as a nuclear industrial center since 1943 when it was selected by the Federal government as the location for construction of one of the world's first nuclear production reactors. Since 1943, nine plutonium production reactors and a number of test reactors have been constructed and operated at the Hanford Reservation. 1.2.2.1.2.8 Population. In 1980 approximately 280,000 people were living within a 50 mile radius of the S/HNP Site. Since the Site is situated within the Hanford Reservation, there are no significant concentrations of population within a 10-mile radius. The closest inhabitants occupy f arms located east of the Columbia River, and are thinly spread over five compass sectors. The closest resident is about seven miles south of the Plant. The nearest population centers are the Tri-Cities area of Richland (15 miles to the south-southeast), Pasco (23 miles to the southeast), and Kennewick (23 miles to the SSE-SE); Benton City (16 miles to the south); Mesa (21 miles to the east-northeast); Prosser (24 miles to the southwest); and Othello (26 miles to the north-northeast) . 1.2-11
/
Amendment 28 u_n .
b LS/ENP-PSAR- -12/21/81 l t t 3'
'2.5:-GEOLOGY,-SEISMOLOGY, AND'GEOTECHNICAL ENGINEERING The_ descriptions of the~ geologic, seismologic,-and f
geotechnical engineering aspects of'the S/HNP Site and -
. surrounding.~ areas are extensive and voluminous in this and *
- other reports because of the. detailed nature and long i' Lhistory..of investigations in the reg' ion. Investigations
-described in this section'of the-PSAR have been coordinated and combined with work Lcarried out for WNP-2 of Washington
-Public Power Supply System. The Supply System has been
- . ' chiefly responsible-for regional geology and seismology;
! . Northwest Energy Services has been chiefly' responsible for
-the S/HNP Site geology and investigation of the Umtanum
' Ridge-Gable-Mountain structural trend. .The essential
' investigations'and results of this and previous studies
, (described in -detail ' in other - parts of Section 2.5) are
, summarized below to provide the reader with an abstract of
~
the work and an overview of the geologic / seismic / geotechnical setting of the S/HNP Site. Intensive studies of the. area in.which the S/HNP Site is [ located have shown that the area is suitable for siting the proposed facilities in terms of both geologic and
- seismologic conditions. These studies have spanned more 23 l_r than 80-years and have, for the most part, been reviewed by the.USNRC and USGS. Despite the exhaustive nature of inves-
. tigations and-the duration over which they have been conducted, little evidence has been found to indicate significant. amounts of recent tectonic activity in the Columbia Plateau. On the contrary, new evidence continues j to indicate a remarkably low degree of tectonic activity.
The S/HNP Site is located within the Hanford Reservation in the Pasco Basin, one ' of several physiographic and structural depressions in the Columbia Plateau underlain by sequences-
, of Miocene basalt and' sedimentary rocks, and partially filled by an assembla'ge of Plio-Pleistocene deposits of
, stream, lake, glacial and wind origin. Subsurface investigations conducted for S/HNP indicate that generally flat-lying. basalt underlies the Site Area and is overlain by approximately 800-900 feet of dense to hard sand, gravel, and clayey silt. The Mio-Pliocene Ringold Formation . -immediately above'the basalt is 500-600' feet thick and
- contains four stratigraphic units that have been traced by borings to~ indicate the presence or absence and nature of structural features.- Flood gravels 200-300 feet thick
. overlie;the Ringold Formation and provide competent' foundation soils for the Plant facilities. Stabilized sand dunes-thinly mantle the ground surface toLdepths of 1-10
. feet. (The-groundwater table i.s at a depth of approximately
-140 feet'below the' surface.
1 2.5-1 Amendment 23-
; .=. __. _ .._..-- .__ _ -_._ u _._.-~.._. -
S/HNP-PSAR 12/21/81 Deformation in the Columbia Plateau which affected the basalts and overlying _ sedimentary rocks occurred largely - during the period 14 m.y. to 3 m.y. BP and resulted in major west- to northwest-trending assymetrical folds (the Yakima folds), subordinate and secondary faults, and minor upwarps and - depressions. Deformation younger than 3 m.y. BP has been found in only a few locations and is typically very subtle.. Although strain rates are not precisely known, geologic and seismologic evidence consistently indicate they must be small and, accordingly, are typical of intraplate tectonic environments. The absence of long faults and large earthquakes further indicates a relatively low degree of tectonic activ y and a low seismic potential for the Site region. The tectonic model that best explains the known geologic and seismologic conditions and their evolution is one in which the Yakima folds are shallow features which originated by buckling within the Plateau basalts in response to regional north-south compression. Some small component of northeast or northwest oriented shearing may have accompanied the buckling, but this shearing was accommodated along numerous and diffuse zones rather than concentrated along discrete faults. This implies that seismogenic structures which may exist in the Plateau have small dimensions and limited potential for earthquakes. Site-specific investigations for the S/HNP were carried out 23 under the direction of NESCO. The three prime contractors
-for geologic, seismologic, geophysical and groundwater investigations were Golder Associates, Weston Geophysical and Battelle. Responsibilities for the investigations were designated as shown below:
Golder Associates - Geology Foundation Engineering Groundwater (field testing
- Weston Geophysical- Seismology (review)
Geophysics Battelle - Groundwater (analysis) All geotechnical work related to S/HNP Site investigations was reviewed and approved by a review panel composed of H. Coombs, R.. Holt, G. Simmons and J. Vance. On a regional scale, evidence favoring the area for nuclear power plant siting includes: e An intraplate tectonic setting 2.5-2 Amendment 23 U
, _ 'S/HNP-PSAR 12/21/81:
1
.e -A lack of'significant or pervasive fau'lts e, Low;ratesfof, deformation !
+-
-e Extensive and little-deformed sedimentary units of Pliocene and younger age o -Low rates-of' seismic activity and e A lack of ~ 1arge-magnitude. earthquakes.
. Geologic knowledge of the Columbia. Plateau and the Pasco Basin-has. evolved over nearly a. century of investigations and has been reported in over 3000 publications (Ref 1).
Ranging from regional-reconnai~ssance scale.t.o very detailed site-specific and feature-specific scale,.the. studies have been conducted.for a. broad spectrum of purposes: academic, resource, facility construction and environmental .
- protection. The investigations have yielded information
-that is impressive in amount and' variety. Table 2.5-1 provides ' a chronology by category of some of the previous investigations that have formed. the basis for the site-specific studies conducted for the S/HNP Site. It shows, together with the studies described below, thatLgeologic, seismologic, and geotechnical investigations relevant to
- - design 'arWI construction of S/HNP have been comprehensive and -
-adequate. Furthermore, the table shown that the Hanford Reservation is virtually. unequaled in the United States with regard to the quantity and quality of data applicable to design of critical facilities.
The approach to studies conducted for the-S/HNP Site was 23 4 based on the concept of verifying previously indicated suitable conditions in the Site Area and selected surrounding areas. The techniques employed to verify these conditions included: , o Field Mapping , o Trenching-
,- - Logging Sampling '
In-Situ Testing \ e ~ Rotary'and Core. Drilling Logging , Sampling In-Situ Testing I
' e' -Petrologic Analyses- >
Binocular and Petrographic Microscope
- 12.5-3 Amendment-23 8
7.s y 9 T-- *--^+v're- '* Tvd '*v-f'"-'e'ev'9* *T w-
- fevt v---e 1W-Tw etT*** vrur'Tve*'*^~* ****N'F-+rr-T*TTM e-"f-'F'9*'TP9' 9
- S/HNP-PSAR 10/14/82 o Downhole Geophysical Logging Neutron-Epithermal Neutron Natural Gamma Neutron-Gamma Gamma-Gamma o Ground Gravity and Magnetic Surveys o Seismic Surveys Seismic Refraction Downhole-in-situ velocity measurements Crosshole in-situ velocity measurements o Laboratory Testing o Geochemical Analysis Based on the investigations performed for the S/HNP Site, the Site has been found suitable for locating the proposed facilities in that it meets the criteria of Appendix A to 10 CFR 100. The investigations have also been adequate to satisf y the requirements of Regulatory Guide 1.70 and Standard Review Plans. Specifically, the investigations have shown:
o There is no potential for ground rupture and no need to consider surface displacement in the Plant design. o The subsurface soils are competent to provide f oundation support f or Plant structures under both static and dynamic loading conditions, and there are no areas of active or potential subsidence, uplif t or collapse. o The groundwater table in the Site Area will remain approximately 100 f eet below f oundation grade, and will not significantly influence, or be influenced by Site-facility water use. The maximum acceleration at the Site resulting from historical or instrumental earthquakes is estimated to have been 0.015g (see Section 2.5.2.6 WNP-2 FSAR). A Regulatory Guide 1.60 Spectrum anchored at a peak acceleration of 0.35g is assigned as the Saf e Shutdown Earthquake (SSE). The requirements of this SSE exceed those for all potential earthquakes discussed in Section 2.5.2.4. 2.5-4 Amendment 28
/
S/HNP-PSAR 12/21/81 2.5.1 BASIC GEOLOGIC AND SEISMIC INFORMATION 1 2.5.1.1 Regional Geology I Information regarcing the geology and geologic hazards of ; the region surrounding the Skagit/Hanford Nuclear Project Site is described in Sections 2.5.1.1 through 2.5.1.2.6 of Amendment 18 (October, 1981) to the WNP-2 FSAR and the Washington Public Power Supply ;em's responses to WNP-2 Questions 361.16, 361.17, 361.20 through 361.25 and $$ additional information transmitted to NRC by the Supply System on April 26, 1982 (Letter, Bouchey to Schwencer) and ] is incorporated herein by reference. This information is supplemented by Appendix 2S to the Skagit/Hanford Nuclear Project PSAR which synthesizes the presently available data bearing on the causative mechanism f or def ormation of the Yakima Fold Belt. 2.5.1.2 Site Geology The Skagit/Hanf ord Nuclear Project (S/HNP) Site Area (2-mile radius) was studied in detail to determine the lithologic, stratigraphic, and structural geologic setting. The regional geologic setting, investigated in cooperation with the Washington Public Power Supply System, is described it. Section 2.5.1.1 cf the WNP-2 FSAR, Amendment 18. Investi-gative methods employed in the Site Area included surface geologic mapping, photogeologic analysis, drilling, borehole geophysical logging, sedimentary petrologic studies of drill core and cuttings, and gravity, magnetic, and seismic refraction studies. These investigations supplemented previous investigations noted in the introduction to Section 2.5 of this PSAR. Data from the S/HNP investigations show that the basalt topog-raphy in the Site Area is generally flat, with some minor local warping. The late Miocene to early Pliocene Ringold Formation is def ormed over bedrock highs; however, overlying late Pliocene (?) to late Pleistocene flood gravels are generally flat-lying, suggesting tectonic stability since post-Ringold time. The findings of the Site investigation are consistent with those f rom other local and regional investigations, generally af firming the regional data with respect to amount, nature, and rate of deformation. No evidence for f aulting has been observed in the Site Area and no capable f aults have been found within 5 miles of the Plant Site. Accordingly, there is no need to consider surf ace f aulting in the design of the Plant. The Skagit/Hanford Nuclear Project Site Area is in the east-central parP. of the Pasco Basin, a depression that is partially filled by alluvial and lacustrine sediments of the late Miocene to early Pliocene Ringold Formation. The 2.5-5 Amendment 23
S/HNP-PSAR 12/21/81 Ringold Formation is underlain by a thick sequence of basalt flows of the Tertiary Columbia River Basalt Group and associated interbeds. Sediments overlying the Ringold Formation in the basin include the late Pliocene (?) to late Pleistocene Pre-Missoula and Missoula Flood Gravels (informal names) and Holocene eolian deposits. This stratigraphic assemblage provides the basis for evaluating the presence or absence and nature of geologic features important to Site safety, i.e., potential earthquake sources, zones of potential ground rupture, and foundation support conditions. The regional context of the Site stratigraphy is described in Section 2.5.1.2.2 of the WNP-2 FSAR, Amendment 18. The Plant facilities are near the axis of the buried Cold Creek syncline, a structural depression bounded on the north by the Umtanum Ridge-Gable Mountain structural trend and on the south by the Yakima Ridge and Rattlesnake Hills anti-clines. The regional context of the Site Area structural geology is described in Section 2.5.1.2.4 of the WNP-2 FSAR, Amendment 18. Within the Cold Creek syncline, minor deformation of the basalt bedrock surface was initiated at least 14 million years (m.y.) ago (Ref 1) and appears to have continued into Ringold time (10.5 to 3.3 m.y. ago). Very minor deformation may have occurred in Post-Ringold time; however, the Site Area is characterized by relative structural stability, consistent with regional evidence for 23 low pre-historic and historic seismicity. The closest fsult to the Plant facilities has been recognized in the subsurface on the Southeast anticline (informal name), 5.5 miles northeast of the Plant facilities (Appendices 2K, Section 5.3, and 2R, Section 6.2.1). The closest faults that are associated with the displacement of Pleistocene deposits are the Central and South faults on Gable Mountain (Appendix 2I, Section 6.1 and 6.2), 8 and 7.5 miles, respectively, northwest of the Plant facilities. The regional setting and tectonic evolution of faults are described in Section 2.5.1.2.4 of the WNP-2 FSAR, Amendment 18, and in Appendices 2K, 2N, and 20 of this PSAR. 2.5.1.2.1 Site Physiography The Pasco Basin, a physiographic and structural depression within the Columbia Basin subprovince of the Columbia Plateau physiographic province, is a 2,000-square-mile, gently undulatory, semi-arid plain interrupted by low-lying hills and sand dunes dissected by intermittent streams. The regional setting of the Site Area physiography is described in Section 2.5.1.1.2 of the WNP-2 PSAR, Amendment 18. The 2.5-6 Amendment 23
S/HNP-PSAR 12/21/81 Pasco Basin is surrounded on three sides by pronounced topographic ridges: the Saddle Mountains form the northern boundary; Umtanum and Yakima Ridges plunge into the basin from the west; and the Rattlesnake Hills and Horse Heaven Hills form the southern boundary. The eastern edge of the basin is poorly defined topographically; it is characterized by relief formed only by sand dunes and coulees. The major drainage through the basin is the Columbia River, entering f rom the north at Sentinel Gap through the Saddle Mountains and exiting the basin through Wallula Gap in the south. The Yakima River enters the Columbia River from the west, south of Richland, and the Snake River joins the Columbia from the east at Pasco. The Site lies approximately 7 miles south-west of the Columbia River at its nearest approach. The Site Area is in the east-central part of the Pasco Basin, a gently undulatory plain mantled with Pleistocene glaciofluvial flood deposits and Holocene eoliar deposits. Figure 2.5-1 shows the topography of the Site Area (2-mile radius). Topographic relief of the Site Area averages approximately 20 ft, with an average elevation of 540 ft above mean sea level. The Plant facilities are located in a stable sand dune area not subject to migration by wind. A small active dune field is present 1 mile to the north in section 28. A much larger active dune field, comprised mainly of transverse dunes, is located east-northeast of the Site and extends to the 23 Columbia River. Prevailing dune migration direction is to the northeast, away from the Site. Several isolated patches of lag deposits, forming a desert pavement, are scattered throughout the dune deposits. The physiographic development of the Pasco ktsin was initiated by downwarping and folding of the Columbia River Basalts in late Cenozoic time, with anticlinal folds forming the prominent ridges and mountains of the region. The structural basin was filled by Ringold Formation sediments in late Miocene to early Pliocene time and by Pre-Missoula flood gravels in late Pliocene (?) to late Pleistocene time. Periodic catastrophic glacial flooding deposited Missoula glaciofluvial gravels in the basin in late Pleistocene time (Ref 2) and was largely responsible for forming the present topographic configuration of the basin. Aggradational land-forms in the Site Vicinity resulting from the glaciofluvial flooding include sheet deposits, flood bars, and current ripples (Ref 1). Bergmounds, isolated mounds of till-like material deposited by grounded, debris-laden icebergs, occur locally in the Site Vicinity (Ref 3). Subsequent eolian processes have formed dune fields over most of the Pasco Basin. The present physiography of the Pasco Basin reflects a mature geologic environment undergoing very slow modifica-tion of the landscape. 2.5-7 Amendment 23
S/HNP-PSAR 12/21/81 2.5.1.2.2 Site Lithology and Stratigraphy , The geologic map of the Site Vicinity (5-mile radius. Figure 2.5-2), based on mapping published in Ref 1, Figure III-1, was verified by supplemental ground inspection and photo-geologic studies. The subsurface geology in the region surrounding the Site was investigated in a total of 114 drillholes. The detailed analysis of the stratigraphy and structure of the Site Area (2-mile radius) was based on 25 rotary holes and two coreholes. The data from these drill holes were evaluated in concert with geophysical studies described in Appendices 2K and 2L of this PSAR, and in conjunction with regional studies described in Section 2.5.1.2.2 of the UNP-2 FSAR, Amendment 18. Previous work on the stratigraphy of the Pasco Basin is noted in the Intro-duction to Section 2.5 of this PSAR and in Appendix 2R. A complete description of the stratigraphic investigation of the Site Area and logs of all drillholes are included in Appendix 2R of the PSAR. Locations of the drillholes in the Site Area are shown in Figure 2.5-3. The findings of this investigation correlate well with pre-vious studies of regional stratigraphy and provide important details that contribute to an improved understanding of Site geology, particularly regarding stratigraphe subdivisions, contacts, age, and deformation. This understanding is the basis for confidence that the location and age of structural features important to the SSE determination are known (as described in Section 2.5.1.2.3), and that the geotechnical properties for foundation design have been defined (as 23 described in Section 2.5.4 and Appendix 20). 2.5.1.2.2.1 Stratigraphy. The stratigraphic section of the S/HNP Site Area is illustrated on Figure 2.5-4. This stratigraphic section is equivalent to part of the previ-ously defined section for the Pasco Basin (Ref 1, 4). Two basalt flows, the Pomona and Elephant Mountain Members of the Saddle Mountains Basalt Formation of the Columbia River Basalt Group, and the Rattlesnake Ridge interbed of the Ellensburg Formation were identified beneath the Site. These rocks are of middle to late Miocene age. Alluvial and lacustrine sediments of the late Miocene to early Pliocene Ringold Formation unconformably overlie the Elephant Mountain basalt. The Ringold Formation is mantled by late Pliocene (?) to late Pleistocene Missoula and Pre-Missoula Flood Gravels, which are, in turn, overlain by Holocene dune sands. The sedimentary section overlying the basalts has been further refined and subdivided in the area surrounding the Site to facilitate stratigraphic correlation and structural interpretation (see Appendix 2R). 2.5-8 Amendment 23
- . . -. - .-- =-. - . .
S/HNP-PSAR 12/21/81 t Correlation of the' geologic units at the S/HNP Site Area was made on the basis of stratigraphic position, lithology, and borehole geophysical characteristics. Basalt flow members 1' Tere. identified by.means of geochemical (X-ray fluorescence) analysis (Appendix-2R, Section 5.1 and Table 2R-1). Stratigraphic. correlations at the Site Area are shown on 4 Figures 2.5-5 through 2.5-8. 2.5.1.2.2.2 Lithology 2.5.1.2.2.2.1 Columbia River Basalt Group. Based on interpretation of X-ray fluorescence (XRF) analyses, the uppermost basalt uaderlying the Ringold Formation in the Site Area is the. Elephant Mountain Member of the Saddle l. Mountains Basalt Formation of the Columbia River Basalt Group. The Elephant Mountain Member has been dated as 10.5 m.y. (Ref 5). This flow is vesicular and commonly weathered to an olive-gray clay near the top, becoming non-vesicular and black to reddish-brown or brown with depth. Five drill-holes that penetrated the Elephant Mountain Member indicate i that the thickness in the Site Area ranges from 140 to 160 feet. Underlying.the Elephant Mountain flow is the Rattlesnake , Ridge interbed of the Ellensburg Formation, a sedimentary unit which interfingers with flows of the Yakima Basalt 23 ! Subgroup. Sediments of the Rattlesnake Ridge interbed [ penetrated by five dri11 holes in the Site Area are comprised of sand to silty sand, silt, and clay. The unit has been correlated with the Rattlesnake Ridge interbed based on its position between the Elephant Mountain and Pomona flows. , This interbed ranges in thickness from 50 to 85 ft in the Site Area. t The Rattlesnake Ridge interbed is underlain by the Pomona Member of the Saddle Mountains Basalt Formation of the Columbia River Basalt Group. The Pomona Member has been dated as 12 m.y. (Ref 5). This flow is commonly vesicular i and weathered near the top. 2.5.1.2.2.2.2 Ringold Formation. - The Ringold Formation unconformablynoverlies the Elephant Mountain basalt in the Site Area and, where measured, ranges from 305 to 570 ft in thickness. Table 2.5-2 shows the suggested correlation of the stratigraphic section of the Skagit/Hanford Nuclear Project Site Area.with that of Ref 1 for the Pasco Basin. Myers and Price ~ (Ref 1) recognized.four textural facies within the Ringold Formation: (1) a basal gravel facies on top of the basalt: surface, (2) a lower facies of silty sand g 2.5-9 Amendment 23
S/HNP-PSAR 12/21/81 to sandy silt with gravel stringers, (3) a middle conglom-eratic facies, and (4) an upper facies of silt, sand, and clay. For purposes of this study, the Ringold Formation has been subdivided within the Site Area into four units on the basis of detailed geophysical and lithologic analyses (Appendix 2R, Section 5.2). These units are referred to as I through IV, with Unit I being the oldest. - The maximum age of the Ringold Formation, limited by the age of underlying Elephant Mountain basalt, is 10.5 m.)f. (late Miocene). However, Tallman, Lillie and Fecht (Ref 6) inter-pret the basal part of the Ringold Formation to be younger than the Ice Harbor Member of the Saddle Mountains Basalt Formation. The Ice Harbor Member has been dated as 8.5 million years old (Ref 5). The upper Ringold facies exposed in the White Bluffs contains vertebrate fossils which are 3.7 to 4.8 million years old (Ref 7). This indicates that the predominantly reversed magnetic section at the White Bluffs recognized by Packer and Johnston (Ref 8) represents the Gilbert Reversed Epoch (5.12 to 3.32 million years). The fine-grained sediments in the upper part of Unit IV in the Site Area are considered to be stratigraphically equiva-lent to the upper Ringold facies in the White Bluffs. Thus, the age range of the Ringold Formation in the Site Area is considered to be between 10.5 and 3.32 m.y. (late Miocene to early Pliocene). The four units of the Ringold Formation each consist of a 23 generally fining-upward sedimentary sequence, with gravel or sand at the base overlain by fine sand, silt, or clay at the top. The basal gravel of each unit is considered to represent a fluvial channel environment, possibly a pebbly braided stream, whereas the sands are interpreted to be flood plain deposits. The fine-grained sediments at the top are interpreted to be overbank and lacustrine flood plain deposits. The abundance of nonbasaltic clasts in the gravels indicates deposition from a through-flowing stream draining distant highlands. Cementation by calcite and clay in the Ringold Formation is variable, ranging from none to well-cemented. Each unit is interpreted to be bounded by erosional unconformities. The nature, thickness, extent, and age of the Ringold units are significant because they contribute information on the location and age of structural deformation during Ringold time (approximately 10.5 to 3.32 m.y. B.P.). The four units and their distinguishing characteristics are discussed below. }lnit I Unit I is lowermost in the Ringold section and is subdivided into a basal gravel and an upper section of silty clay to ) clayey silt with some sand. The basal part is comprised of 1 moderately well-cemented sandy gravels to gravelly sands 2.5-10 Amendment 23
S/HNP-PSAR 12/21/81 l having dominantly basaltic clasts at the base, with increasing quartzite, granitics, and rare volcaniclastics higher up in the unit. Mafic grains in the matrix sand commonly have a distinct bluish color. Based on strati-graphic position and texture, these gravels are considered to be equivalent to the basal Ringold facies defined by Ref
- 1. The upper part of the unit is interpreted as a paleosol which is distinguished by its olive-gray to light-olive-gray color. Based on stratigraphic position and texture, the fines of upper Unit I are considered equivalent to the lower part of the lower Ringold facies defined by Myers and Price (Ref 1). Unit I ranges in thickness from approximately 118 to 177 feet in the Site Area.
Unit II Unit II is composed of yellowish-gray to very-light-olive-gray clay, silt, and sand with a gravel horizon near the base. The clays commonly have a distinctive waxy luster. The gravel horizon is typically ferruginous-stained and contains stringers of sand, silt, and clay. Gravel clasts generally have a yellow-brown cementation rind with adhering sand grains. Clasts consist of basalt, quartzite, volcani-clastics, and granitics. Based on stratigraphic position and texture, Unit II is considered to be equivalent to the middle and upper parts of the lower Ringold facies defined by Myers and Price (Ref 1). Unit II ranges in thickness - from approximately 116 to 146 feet in the Site Area. Unit III 23 Unit III consists of interfingered sandy gravel and gravelly sand in the lower part of the unit, overlain by sand, silt, and clay in the upper part of the unit. Gravel clasts are basalt, quartzite, gneiss, granitics, and volcaniclastics, and commonly have yellowish cement rinds with adhering sand grains as in Unit II. Fine sediments in the upper part of the unit are interbedded yellowish-gray sand and silty sand with clayey silt or silty clay at the top. Based on stratigraphic position and texture, Unit III is considered to correlate with the gravels of the middle Ringold facies defined by Myers and Price (Ref 1). Unit III ranges in thickness from 0 to approximately 99 ft in the Site Area. Unit IV Unit IV consists of basal sandy gravel to gravelly sand overlain by interbedded yellow-gray to dusky-yellow silt, sand, silty sand, and sandy silt. Gravels in the basal part of Unit IV are lithologically like those in the base of Unit III. These gravels are also considered to correlate with the middle Ringold facies of Ref 1. Fine-grained sediments 2.5-11 Amendment 23
S/HNP-PSAR 12/21/81 'in the upper part of Unit IV are considered to correlate with the basal part of the upper Ringold f acies of Ref 1. A thick sequence of Upper Ringold sediments is exposed in the White Bluffs east of the Site. Most of this upper'part of 'the Ringold section has been eroded from the Site Area. Thickness of Unit IV in the Site Area ranges from 0 to approximately 184 ft. 2.5.1.2.2.2.3 Pasco Gravels. The Pleistocene Pasco Gravels of the Hanford Formation (Ref 1, 4) have been subdivided in the Site Area into Pre-Missoula and Missoula Flood Gravels (informal names). Pre-Missoula Flood Gravels unconformably overlie the Ringold Formation in the Site Area and contain clasts that are dominantly composed of gcanite, quartzite, gneiss, and porphyritic volcanics derived _n part from the Ringold Formation. The clasts are well-rounded and gener-ally lack matrix. Weathering rinds on basalt clasts are thin and poorly developed. Thin, light gray to white, well-sorted, medium- to coarse-grained sand beds are occa-sionally present within these gravels. Pre-Missoula Flood Gravels are generally uncemented, but some horizons are locally cemented with calcium carbonate or clay. These gravels form a channeled, sheet-like deposit across the Site Area. A flat-lying high-velocity seismic refracting layer (8,000-10,000 ft/sec) is present in the lower part of the Pre-Missoula gravels (Appendix 2L, Section 4.4.1.2). Although the provenance and age of the gravels have not been de te rmined , their fabric, composition, and lateral extent suggest that they represent large-scale flood deposits, 23 possibly from late Pliocene flood episodes or early to late Pleistocene glaciofluvial flood episodes which were restricted to the Spokane River and Columbia River drain-nges. These gravels are equivalent to the basal part of the Pasco Gravels of the Hanford Formation defined by Myers and Price (Ref 1). Because the Pre-Missoula Flood Gravels can be distinguished from Ringold gravels by the lack of yellow cement rinds and from overlying Missoula Flood Gravels by greater than 50 percent nonbasaltic clasts, they are recog-nized as a separate stratigraphic unit in the Site Area. The age of these gravels is uncertain, but could be as old as 3.3 m.y. Thickness of the Pre-Missoula gravels in the Site Area ranges from approximately 93 to 223 ft. The Pre-Missoula gravels are widespread throughout the Site Area, and contribute to information on the location and age of structural deformation in post-Ringold time (3.32 m.y. to 17,500 years B.P.). Missoula Flood Gravels are present across the Site Area. These gravels unconformably overlie the Pre-Missoula Flood Gravels and are capped by active or stabilized Holocene dune sands. They are uncemented pebble to cobble gravels which l 2.5-12 Amendment 23
S/HNP-PSAR 12/21/81 commonly contain interbedded coarse sands. The gravels are characterized by a dominance of basalt, commonly 95 percent, with a few clasts of granitics and metamorphics. The sands are dark gray from the high basalt content, but also contain quartz, feldspar, and mica. Missoula flood gravels are distinguished from Pre-Missoula gravels by the presence of greater than 60 percent basalt in the gravels and sand. , They formed as the result of large-scale catastrophic floods released from glacial Lake Missoula in Montana (Ref 9, 10, 11). Missoula flood deposits have been assigned an age range of 13,000 years B.P., based on the presence of St. ; Helens "S" ash near the top of the unit (Ref 12), to 17,500 to 18,000 years B.P., based on the age of the last major glacial advance in the northern United States (Ref 13). They are equivalent to-the upper part of the Pasco Gravels of the Hanford Formation as defined by Myers and Price (Ref 1). Thickness of the Missoula Flood Gravels in the Site Area ranges from approximately 25 to 85 ft. Missoula flood gravels are the chief materials to be involved in the Site excavation. Their foundation engineering propert'.es are good and are described in Section 2.5.4 and Appendix 20 - 2.5.1.2.2.2.4 Surficial Deposits. Figure 2.5-2 shows the surface geology of the vicinity within a 5-mile radius of the Plant facilities. Surficial deposits include active and stabilized Holocene dune sands, Holocene alluvium, and Pleistocene glaciofluvial sediments. In the southwestern part of the map, the Touchet beds of Flint (Ref 14) repre-sent fine-grained, slackwater sediments deposited distally 23 from the main Pleistocene flood channels. In the Site Area (2-mile radius), a thin mantle of active and stabilized Holocene dune sands blankets the Pleistocene . Missoula Flood Gravels. These sands are fine- to medium-grained quartzose or basaltic sands which commonly contain silt (Ref 1). Sparse vegetation stabilizes most of the dunes. The eolian deposits range in thickness from 1 to 10 ft in the Site Area. Most of the surficial deposits will be removed or compacted during Site development and pose no problems for facility design and operation. 2.5.1.2.3 Site Structural Geology The S/HNP Site Area is in the east-central part of the Pasco Basin, a structural sub-basin of the larger Columbia Basin. The Pasco Basin is partly surrounded by west- and northwest-trending anticlinal ridges, the Yakima Folds, which are separated by broad synclinal troughs. The Saddle Mountains form the northern boundary of the Pasco Basin, and 2.5-13 Amendment 23
.g S/HNP-PSAR 10/14/82 4
the Rattlesnake Hills and . Horse Heaven Hills f orm the southern boundary. Umtanum Ridge and Yakima Ridge plunge eastward into the basin at the western boundary. The eastern boundary of the basin is formed by. a gentle westward dip on the basalt surface. The Plant Site is near the axis of the Cold Creek syncline, a buried structural depression between Gable Butte-Gable Mountain-Southeast anticlines on
~the. north and northeast, and the Yakima Ridge anticline on the west and southwest.
I Investigations for S/HNP drew on previous knowledge of local and regional geologic structure (refer to Section 2.5.1.1 of the WNP-2 FSAR, Amendment 18) to develop specific information critical to identifying and characterizing all structures significant for seismic design. ! Detailed photogeologic analyses, field mapping and sub-surface stratigraphic studies have not identified any 2 faulting within the Site Area. The closest fault to the Plant f acilities is 5.5 miles to the northeast on the South-east anticline, the buried easterly segment of the Umtanum Ridge-Gable Mountain structural trend. This fault was recog-nized on the basis of an anomalous thickness of the Elephant Mountain flow containing several thin zones of shearing in Corehole 125. Closely spaced coreholes were drilled by Golder Associates for the Washington Public Power Supply System to determine the attitude of this fault and the conti-nuity of overlying-Ringold units (Ref 22). The fault is a reverse f ault. It strikes N39ow and dips 300SW. The range of vertical displacement on the f ault is 35 to 60 feet. Based on this small amount of displacement, the Southeast
; anticline fault appears to be a minor feature and probably i does not extend any significant distance away from corehole 125.
3 The sediments. overlying the projection of the fault plane gy i have been penetrated by 11 holes spaced 30 to 100 f eet apart ' along a line 450 feet long. These overlying sediments include'the late Miocene lower Ringold Formation (approxi-mately 10 million years old) and the Pleistocene Hanford Formation. Fine-grained units within the Pre-Missoula Gravels of the Hanf ord Formation near corehole 125 have been dated on the basis of paleomagnetic analyses as older than 730,000 years. Four stratigraphic contacts, ranging in age , from approximately 10 million to at least 730,000 years in age, dip gently across the projection of the fault plane and show no abrupt changes in elevation. Based on these observa-tions, the Southeast anticline fault has not been active for approximately 10 million years and is therefore not capable. The South fault, 7.5 miles north on the south flank of Gable Mountain, is the closest known fault to the Plant facilities <'34 l l 2.5-14 Amendment 28
.- . -. . .--. . - - - - - _-. - _. . ~ . - . -
S/HNP-PSAR 10/14/82 which is associated with displacenent of Pleistocene sedi-ments (Appendix 20, Section 6.2.3). The South fault is inferred to have moved in late Pleistocene time on the basis -of deformation observed in clastic dikes present along the fault. The Central fault, 8 miles to the northwest on Gable Mountain, has displaced overlying Missoula glaciofluvial deposits (dated at 13,000-17,500 B.P.) in a reverse sense a maximum of 0.2 f t (Appendix 20, Section 6.1.3). l gl \ 1
,q%
'N 2.5-14a Amendment 28
S/HNP-PSAR 12/21/81 Displacement in the glaciofluvial deposits has been observed over a lateral distance of approximately 1,100 ft, although the fault in the basalt bedrock extends over a greater dis-tance. The origin of the displacements in the glaciofluvial deposits has not been determined. Several alternative mechanisms for the origin of the displacements have been considered, including tectonic activity, landsliding and flood-induced stress release (Appendix 20, Section 7.2). Although some evidence supports nontectonic hypotheses for the origin of the displacements, insufficient data are available to demonstrate a nontectonic origin. Figure 2.5-9 shows the structural geology of the Site Area based upon structural contours drawn on top of the uppermost basalt surface, identified by XRF analysis as the Elephant Mountain Member. The top of basalt was established by downhole geophysical logging techniques in combination with lithologic identification of core chips and rotary drillhole cuttings from 26 drillholes which encountered basalt. The resolution in establishing the flow top is estimated to be about + 5 ft. Contours were extended beyond the limits of the drillhole data based on structural trends indicated on ' the gravity map of the Site region (Appendix 2L, Figure 2L-11). The structure contour map (Figure 2.5-9) shows that the basalt surface underlying the Site Area is of generally low relief, with typical slopes on the order of 1 degree or less. The relief on the surface of the basalt is as=umed to be the product of gentle warping that has formed two 23 distinguishable features in the basalt: the Cold Creek syncline in the central part of the Site Area, and a small east-west trending casalt high in the vicinity of drillholes S-6, S-8, S-9 and S-11 in the northwestern part of the Site Area. The Cold Creek syncline, a broad assymetrical trough with gently-sloping limbs (5 degrees maximum), trends northwest-southeast through the Site Area and plunges gently to the southeast. A local depression approximately 150 ft deep exists along the axis of the syncline in the vicinity of drillhole S-16. The small east-west basalt high exists on the northern limb of the Cold Creek syncline, rising approximately 100 ft above the surrounding bedrock surface. It is less prominent along its southeastern extent toward drillholes S-10 and S-11. The maximum gradient on this high is approximately 3.5 degrees and occurs on its northern side in the vicinity of dri11 holes S-6 and 15. The east-west high (in the vicinity of dri11 holes S-6 to S-11), the southwestern limb of the Cold Creek syncline, and the depression in the vicinity of drillhole S-16 are locally reflected in the overlying Ringold units. Consistent thick-ness of Units I and II and reduced thickness of Units III 2.5-15 Amendnient 23
- .. . =_ -. .
S/HNP-PSAR 12/21/01 and IV suggest folding on these structures during Unit III and IV time. Slight changes in elevation of the base of the Pre-Missoula Flood Gravels across these features suggest minor warping during post-Ringold time. There are no known capable faults within 5 miles of the Plant _ facilities and no structures have been identified which'might influence the seismic design of the Plant facilities. The geologic structures that have been found in the Site Area are consistent with those of the region and with the seismic design described in Section 2.5.2. 2.5.1.2.4 Site Geologic History Extrusion of the Columbia River Basalt Group into the Pasco Basin began between 14 and 16.5 million years ago (Ref 1). The Elephant Mountain basalt flow, the youngest flow in the
- Site Area, was extruded 10.5 million years B.P. (Ref 5).
- During intervals between lava extrusions, fluvial and lacustrine sediments were deposited on the basalt surface. ,
, This basalt and sedimentary interbed section may attain thicknesses of greater than 10,000 ft in some portions of the Pasco Basin (Ref 15). After extrusion of the Elephant Mountain flow, the area was subjected to a period of sub-aerial weathering. Subsequently, a series of four fining-upward sedimentary units were deposited over the basal Ringold gravels. These units (Units I-IV.of the Ringold
- Formation) range in age from late Miocene to early Pliocene 23 and record cyclic depositional patterns reflecting inter-acting changes in the source area and base level for the Pasco Basin.. Minor warping of the older Ringold units and the absence of the upper Ringold units over localized bedrock highs in the Site Area suggests that the Site deformation, which began at least 14 million years ago (Ref 1), continued into Ringold time.
The Pre-Missoula and Missoula Flood Gravels which overlie the Ringold Formation were deposited at least in part by catastrophic glacial floods which sculptured much of the Columbia Plateau. The youngest of these, the Missoula Flood Gravels, were deposited from flood waters emanating from glacial Lake Missoula in late Pleistocene time (approxi-mately 13,000-17,500 years ago). The oldest of the flood gravels (Pre-Missoula Flood Gravels) may also have been deposited from similar Pleistocene glacial events or may
- have been deposited from much earlier (late Pliocene?)
floods. Within the Site Area, the-generally flat-lying contact at the base of the Pre-Missoula Flood Gravels show
- that no significant deformation has occurred since these - sediments were deposited. Thus, geologic history of the 4
l 2.5-16 - Amendment 23
-w_--. .-.-.r.-- ,e, p =-c w-, -,~v--rr- --e , , , ---=
S/HMP-PSAR 12/31/81 Site Area and the Columbia Plateau indicates that the region has been tectonically stable compared to other parts of the Pacific Northwest and western North America. In addition, recent geologic and seismic history are mutually consistent and indicate a low potential for earthquakes. 2.5.1.2.5 Engineering Evaluations of Local Geologic Features Geotechnical investigations were performed to evaluate foundation conditions at the Plant facilities and to provide engineering data and analyses required for the design of foundations and subsurface walls under both static and dynamic loading conditions. The scope of the study included field and laboratory investigations, together with engineet-ing evaluations for foundation design. The field program comprised subsurf ace borings, trenching, in situ deformation testing within boreholes and trenches, subsurface soundings, in situ density measurements and undisturbed sampling for laboratory testing. The details of the field program are discussed in Appendix 2Q of this PSAR. In addition, field seismic surveys were undertaken at the Plant facilities (Appendix 2L of this PSAR) and a groundwater monitoring system (water sampling and piezometric head monitoring) was established (Appendix 2P of this PSAR). Supplemental infor-mation was obtained from general observations during the geologic investigations. 23 There are no areas of actual or potential surface or subsurface subsidence, uplift or collapse at the Plant facilities. There exist no deformational zones, shears, Joints, fractures or folds, zones of alteration, structural weakness or irregular weathering profiles which would have an influence on structural foundations. There is no evidence of faults or disturbances from past earthquakes within the foundation soils. Basalt bedrock is at a depth of approximately 700 feet at the Plant facilities, and unrelieved residual bedrock stresses would not impact , structural foundations. The Plant facilities soils are derived from predominantly basaltic and silicic rock types that are chemically stable, and will not exhibit instabil-ities related to physical or chemical properties. The Site Area has not been affected by sc5 grade mineral extraction and there are no known minerals of commercial value specific to the Site Area. Recent reports of possible commercial natural gas in an exploratory well north of Yakima may result in the Pasco Basin being classified as a gas-producing basin. 2.5-17 Amendment 23
S/ENP-PSAR 8/16/82
.The Pls nt f acilities are underlain by about 35 f t of medium dense to dense sand to approximately elevation 490 f t (MSL), #
about 170 f t of very dense sand and gravel to approximately elevation 320 ft, and about 520 f t of very dense sand and gravel with hard clayey silt down to basalt bedrock at about i elevation -200 f t. The bearing capacities of the Plant f at'lities soils will be very large f or the mat f oundations of the major central plant structures, and settlements will . be small. Because of the depth of the water table (approxi- l mately 100 f t below foundation grade) and the nature and ; i strength of the soils below the water table, the foundation ' materials are not susceptible to instability associated with i liquefaction or cyclic-strength deterioration. Accordingly, the subsurface soils at the S/HNP Plant facilities are compe- i tent to provide foundation support for the plant structures j under both static and dynamic loading conditions. In general, overexcavation of soils at f ounding elevations and : replacement with structural backfill will not be required l beneath the central plant f oundations. Details of the found-ation engineering properties of the Plant f acilities are 23 l' described in Section 2.5.4 and Appendix 2Q. i , 2.5.1.2.6 Site Groundwater Conditions I 4 Groundwater occurs at the Site Area under confined and uncon-i fined conditions. Water exists in an unconfined state in the glaciofluvial deposits .and in a confined state in the ! ! Aingold Foruation and basalts. Water in the lower part of j the Ringold Formation is under a slightly higher hydraulic ; head than water in the upper part of the Ringold Formation. ! ! The water table at the Plant f acilities occurs at approxi- l mately elevation 400 f t above mean sea level, which is about j 100 f t below the base of Category I structures. Existing i i water-level data show that the elevation of the water table ! at the Plant Site has fluctuated in response to liquid waste j disposal at the 200-Areas. Groundwater conditions of the , Plant facilities are discussed in detail in Section 2.4.13. j . 2. 5.1. 7. 7 Volcanic dazards i i i volcani'c hazards at the S/HNP Site are the same as those at ! the Washington Nuclear Project No.'2 (WNP-2) site. Those ! hazards are discussed in WNP-2 FSAR (Amend 18), Section i 2.5.1.2.6.1. The only potential volcanic hazard to the 26 i S/ENP Site is considered to be that resulting f rom ashf all from a major eruption of a Cascade volcano. The composite , characteristics of such an ashfall would be as follows: L 2.5-18 Amendment 26 L
,- .-,-.n,,,c,--_,,.,,,
l S/HNP-PSAR 8/16/82 o_ Eruptive Sources: ~ Mount Adams or Mount Rainier at a distance of 165 km and 180 km respectively, l o Estimated Ash Eruptive Volume: Mount St. Helens Layer Yn (4 km3) { o Duration of Ashfall: Approximately 20 hours. o Potential Thickness of Compacted Ashfall: 7.4 cm (3 inches) o Estimated Percent Compaction of Ash: 20-40 per-cent. o Average Rate of Ashfall: .37 cm/hr (0.15 in/hr). 26 o Average Density of Ash: 72 pcf (dry, loose) 96 pcf (dry, compacted) 101 pcf (wet, compacted Estimated Average Grain Size: 98% 0.5 mm 914 0.35 mm 76% 0.25 mm 57% 0.15 mm 50% 0.075 mm 40% 0.040 mm 27% 0.010 mm 20% 0.005 mm 11% 0.002 mm Design criteria for the S/HNP meet or exceed all of the requirements of this postulated ashf all. Operating criteria and procedures addressing such an ashfall will be specified in the S/HNP FSAR. 2.5.2 VIBRATORY GROUND MOTION The S/HNP Site is located approximately 5 miles west of WNP 1/4 and WNP-2 sites. Information on seismicity of the area within a 200' mile radius of the S/HNP Site and the maximum earthquake potential at the S/HNP Site is provided in 23 Sections 2.5.2.1, 2.5.2.2, 2.5.2.3 and 2.5.2.4 of Amendment 18 (October, 1981) to the WNP-2 FSAR and is incorporated herein by reference. I l 2.5-19 Amendment 26
_S/HNP-PSAR 8/16/82
- 2.5.2.1 Seismicity-l Reference Section 2.5.2.1, WNP-2 FSAR.
2.5.2.2 Geologic Structures-and Tectonic Activity 23 Reference Section 2.5.2.2, WNP-2 FSAR. 2.5'.2.3 Correlation of Earthquake Activity with Geologic Structure or Tectonic Provinces 4 Reference Section 2.5.2.3, WNP-2 FSAR. 2.5.2.4 Maximum Earthquake Potential 2.5.2.4.1 Potential Sources of Earthquakes The earthquake potential at the S/HNP Site is defined in the following subsections, in accordance with parameters defined , in'the WNP-2 Draft SSER (June 29,1982) for Section 2.5.2. . 2.5.2.4.1.1 Swarm-Type Earthquake. A swarm-type earthquake (Mg = 4.0) is assumed to occur at the closest approach of major irrigation to.the S/HNP Site. The Columbia River acts as a boundary to the water table influence from major irriga- 26 tion to the north and east of the Hanford Reservetion. To the south and west of the Hanford Reservation, the area under irrigation is limited. Thus, using the guidelines set forth in the WNP-2 SSER, a swarm-type earthquake is assumed to occur to the east of the S/HNP Site at a minimum hypo-central distance of approximately 8 kilometers from the S/HNP Site. Irrigation currently taking place on the Banford Reservation consists of (1) waste discharge to ponds, (2) waste dis-charge to surface cribs and (3) occasional and very minor surface irrigation of solid waste disposal sites for the purpose of establishing vegetative cover. The volumes of water associated with these usages have no significant effects on the groundwater table. 2.5-20 Amenc'ent 26
S/HNP-PSAR 8/16/82 l l 2.5.2.4.1.2 Earthquakes Associated with Tectonic Provinces. The largest earthquake within the Columbia Plateau Tectonic Province assumed to occur in the site vicinity is the 1936 July 16, Milton-Freewater earthquake. The magnitude of this earthquake has been determined to be 5.7-5.8 Ms (WNP-2 SSER, Section 2.5.2). The epicenter of the December 14, 1872 north-central Washington earthquake is located in the Northern Cascades tectonic province whose closest approach is approximately 140-150 kilometers north of the S/HNP Site. This event has been assigned a magnitude Ms = 7.0. 2.5.2.4.1.3 Earthquakes Associated with Tectonic Structure. The Rattlesnake-Wallula (RAW) alignment is the most signifi-cant structure to the S/HNP Site. The closest approach of RAW to the S/HNP Site is 15 kilometers. The maximum cred-ible hypothetical earthquake for the RAW structure has been determined to be MS = 6.5. . A number of faults and structural features are located in the vicinity of Gable Mountain. The closest approach of 26 ! Gable S/HNPMountain and its associated Site is approximately structural features to the 10 kilometers. For licensing purposes, the maximum hypothetical earthquake assumed to be associated with Gable Mountain is Ms = 5.0 (WNP-2 SSER, Section 2.5.2). I 2.5.2.4.2 Vibratory Ground Motion 2.5.2.4.2.1 Ground Motion from Larger Earthquakes. Peak ! accelerations from earthquakes associated with tectonic pro- , vinces (Section 2.5.2.4.1.2) or tectonic structures (Section I 2.5.2.4.1.3) are estimated using attenuation relationships i of Campbell (1981), Joyner and Boore (1981) and Woodward Clyde (7.ppendix 2.5K, WNP-2 FSAR). The highest acceleration t values calculated are for the assumed 6.5 Ms earthquake on ! RAW, a distance of 15 kilometers from the S/HNP Site. i Of the three relationships cited above, it is believed that ! Campbell's relationship is most appropriate for estimating i "close in" ground motion at the S/HNP Site. Neither the Joyner and Boore nor Woodward-Clyde relationships are as i specific as Campbell's relationship to the "close in" dis- ; tances being considered. , Campbell's attentuation relationship for a 6.5 M3 earthquake 6 i at-15 km yields acceleration values of .175g at the median i level and .2579 at the 84th percentile level. The average : j of the acceleration values calculated from the three I attenuation relationships referred to above is 0.201g at the ! l I l i r 2.5-20a Amendment 26 I
S/HNP-PSAR 8/16/82 median level (range of 0.175 to 0.237) and 0.316g at the 84th percentile level (range of 0.257 to 0.345). l Ground velocity values are estimated from the attenuation relationships of Joyner and Boore (1981) and Woodward-Clyde Consultants (1978). The average of the calculated velocity values is 22.19 cm/see at the median level (values of 19.70 and 24.67) and 39.38 cm/sec at the 84th percentile level (values of 37.81 and 40.95). Response spectra were developed using the above ground motion values and spectral amplification factors c stained in NUREG/CR/0098 (Newmark and Hall, 1978). Median pectral amplification factors were used with the 84th percentile ground motion values, and 84th percentile spectral amplifica-tion factors were used with median ground motion values. The two response spectra for an Ms = 6.5 at a distance of 26 15.0 kilometers are shown on Figure 2.5-9a. For comparison purposes, a Regulatory Guide 1.60 Spectra anchored to 0.35g is also shown on Figure 2.5-9a. 2.5.2.4.2.2 Ground Motion from Swarm Earthquake. The ground motion predictions for a swarm-type earthquake of ML = 4.0 were developed by Washington Public Power Supply System in response to Question 361.16 for WNP-2. The Supply System's consultant, Woodward-Clyde Consultants, used "on-linear regression techniques to predict peak acceleras.on as a function of distance. The predicted 84th percentile cor-rected peak acceleration value for a M L 4.0 event at a hypo-central distance of 8.0 kilometers (the closest approach of major irrigation to the S/HNP Site) is .115g. The shape of the response spectrum associated with the swarm-type earthquake was also determined in the response to Ques-tion 361.16 (WNP-2 FSAR). This response spectrum shape anchored to the computed acceleration value of .115g is shown on Figure 2.5-9b. The resonse spectrum for the swarm ' earthquake is compared with the response spectra for the 6.5 Ms earthquake at 15 kilometers distance on Figure 2.5-9c. 2.5.2.5 Seismic Wave Transmission Characteristics of the Site In-situ velocity measurements by crosshole and downhole 23 techniques and surface refraction studies have been conducted in the vicinity of the S/HNP Site (Appendix 2L). The velocity column beneath the S/HNP Site from ground surface to the Elephant Mountain Basalt is shown on Figure 2.5-20b Amendment 26
S/HNP-PSAR 8/16/82 2.5-10. The velocity column has been compiled f rom crosshole l26 velocity measurements at the west reactor site to a depth of approximately 200 ft, from downhole velocity measurements to a depth of 570 ft in borehole S-15, and from surface refraction data for the basalts. Velocity values between a depth of 570 ft and the top of basalt at a depth of 704 ft I have 'been estimated from downhole velocity measurements at other locations as correlated with the coarse and fine materials indicated by the geophysical logs. The coarse 24 materials within the Ringold and lower pre-Missoula section are generally cemented, producing the high velocity (8,000 fps or greater) layers shown on Figure 2.5-10. Shear wave !
' velocities within the Ringold section below a depth of 230 ft are estimated based on velocity measurements at other locations in the Hanford Reservation area. Compressional and shear wave velocities of the materials above basalt have also been measured at WNP-1/4 and WNP-2 (Appendix 2L of the ;23 WNP-1/4 PSAR). The changes in seismic wave velocities with depth at WNP-1/4 and WNP-2 are similar to those described above for the S/HNP.
I The sonic velocities of the basalt flows and interbeds below i the Elephant Mountain Basalt have been measured in the j Rattlesnake Hills No. 1 well (Ref 16) to a depth of 3,230 m (10,600 ft). The sonic log from this well shows that the
, compressional wave velocity varies. Relatively high velocities of 5.0 to 5.7 km/s (16,400 to 18,700 fps) were measured for the competent basalt flows. Lower velocities of 4.0 to 4.5 km/s (13,000 to 14,800 fps) were measured for the interbeds. Shear wave velocities were not measured.
I 2.5.2.6 Safe Shutdown Earthquake S The maximum acceleration at the Site resulting from historical or instrumental earthquakes is estimated to have been 0.0159 (see Section 2.5.2.6 WNP-2 FSAR). A Regulatory Guide 1.60 Spectrum anchored at a peak acceleration of 0.35g is assigned as the Safe Shutdown i Earthquake (SSE) . The requirements of this SSE exceed those for all potential earthquakes discussed in Section 2.5.2.4. 26 2.5.2.7 Operating Basis Earthquake i A Regulatory Guide 1.60 Spectrum anchored at a peak accelera-tion of 0.175g, or one-half that of the SSE, is assigned as i the. Operating Basis Earthquake (OBE). l l l 2.5-20c Amendment 26
S/HNP-PSAR 8/16/82 2.5.3 SURFACE FAULTING e All available geologic and geophysical information was evaluated to determine whether any evidence suggested that , surface faulting.might occur within 5 miles of the Site. ! Available information was supplemented with detailed, , site-specific geologic and geophysical surveys extending ' beyond 5 miles in some directions and concentrated in a 2 ' mile radius of the Site. These surveys have included ground gravity and magnetic surveys along closely spaced lines and a seismic refraction survey. The results of the geophysical investigations are described in Appendices 2K and 2L. Geologic investigations undertaken specifically to supple-ment available information included photogeology, field mapping, rotary and core drilling, and stratigraphic analysis. The results of these investigations are described in Section 2.5.1.2 and Appendix 2R. 23 Geologic and geophysical studies have shown that the basalt bedrock underlying the Site within a radius of at least 2 miles shows slopes with only gentle relief (generally less ' than 5 degrees). Sedimentary units within the Miocene-Pliocene Ringold Formation which overlies bedrock are generally horizontal or show some. miner warping (slopes less than 5 degrees). Sediments overlying the uppermost Ringold Formation (generally considered to be part of the Hanford Formation) are Pleistocene or older in age and contain a refracting horizon of 8,000 ft/sec velocity which is flat-lying within a radius of 2 miles of the Site. This velocity horizon has also been found to be flat-lying over an area of approximately 28 square miles within the vicinity of the Site. There are no photolinears within the Site Area which are structurally controlled. On the basis of these data, there is no evidence that suggests potential for surface faulting; therefore, Sections 2.5.3.1 through 2.5.3.8 do not apply.
\
l + 2.5-21 Amendment 26 I
. .. _ _ _ _ _ _ . _ _ _ _ -__ _ _ .. ._._a
S/HNP-PSAR 12/21/81 References for Section 2.5 (
- l. Myers, C.W., and Price, S.M., Geologic Studies of the
' Columbia Plateau; a Status Report, RHO-BWI-ST-4,
~
Rockwell Hanford Operations, Richland, WA (1979).
- 2. Baker, V.R., and Nummedal, D., The Channeled Scabland, National Aeronautics and Space Administration field conference held on the Columbia Plateau (June 5-6, 1978).
- 3. Fecht, K.R., and Tallman, A.M., Bergmounds Along the Western Margin of-the Channeled Scablands, South-Central Washington, RHO-Bhl-SA-ll, Rockwell danford Operations, Richland, WA (1978).
- 4. Tallman, A.M., and others, Geology of the Se'paration Areas, Hanford Site, South-Central Washington, RHO-ST-23, Rockwell Hanford Operations, Richland,-WA (1979).
- 5. McKee, E.H., Swanson, D.A., and Wright, T.L., " Duration and Volume of Columbia River Basalt Volcanism; Washington, Oregon, and Idano", Geol. Society of America Abstracts with Programs, 9, 4, (1977), p. 463.
- 6. Tallman, A.M., Lillie, J.T., and Fecht, K.R.,
"Suprabasalt Sediments of the Cold Creek Syncline Area", Chapter 3, in Myers, C.W., and. Price, S.M.,
editors,-Subsurface Geology of the Cold Creek Syncline, RHO-BWI-ST-14, Rockwell Hanforo Operations, Richlanc, WA (1981).
- 7. Repenning, C.A., "Biochronclogy of the Microtine Rodents of the U.S.", in Woodourne, M.O., editor,
~
Cenozoic Mammals; Their Tenporal Record, Biostratigraphy, and Blochronology, Univ. of Calif. Press, Berkeley-(in press).
- 8. Packer, D.R., and Johnston, J.M., A Preliminary Investigation of the Magnetstratigraphy of the Ringold Formation, RHO-BWI-C-42, Rockwell Hanford Operations, ,
Richland, WA (1979).
- 9. Bretz, J.H., "The Channeled Scablands of the Columbia Plateau", Journal of Geology, --31, 8, (1923),
- p. 618-649.
- 10. . "The Spokane Flood Beyond the Channeled Scablands", Journal of Geology, 33, 2, (1925),
- p. 97-115. .
( ~ i 2.6-12 Amendment 23
. . . ., . ~ .-- . ..-
S/HNP-PSAR 12/21/81~ , : ll. Baker, V.R., Paleohydrology and Sedimentology of Lake Missoula Flooding in Eastern-Washington, Geol. Society ) of America Special Paper 144, (1973), 79 p.
- 12. 'Mullineaux, D.R., and others, " Age of the Last Major Scabland Flood of Eastern Washington, as Inferred from Associated Ash. Beds of Mount St. Helens Set S," Geol.
, Society of America Abstracts with Programs, 9, 7, (1977),.p. 1105.
- 13. Clague, J.J., Armstrong, J.E., and Mathews, W.H.,
" Advance of the Late Wisconsin Cordilleran Ice Sheet in Southern British. Columbia Since 22,000 Yrs. B.P.",
l Quaternary Research, v. 13, (1980). p. 322-326. .
- 14. Flint,.R.F., " Origin of the Cheney-Palouse Scabland Tract", Geological Society of America Bulletin, 49, 3, i (1938), p. 461-563.
- 15. Reidel, S.P., and others, New Evidence for Greater Than 3.2 km of Columbia River Basalt Beneath the Central
. Columbia Plateau, American Geophysical Union, Fall Mtg., Ellensburg, WA (1981).
t
- 16. Raymond, J.R. and Tillson, D.D., " Evaluation of a Thick Basalt Sequence in South-Central Washington - Geophys-
! ical and Hydrological Exploration of the Rattlesnake 4 Hills Deep Stratigraphic Test Well", Report BNWL-776, j submitted to Atomic Energy Commission, (1968), 126 p.
- 17. American Society for Testing and Materials, Annual book of A!MSL standards, Part 14r Concrete and mineral eggregates, ASTM, Philadelphia, PA (1976).-
- 18. American Society for Testing and Materials, 1981, Annual book of ASTM ntandards, Part 19: Soil and rock;
- . building stones, ASTM Philadelphia, PA (1981).
l 19. Silver, M.L., Laboratory triaxial testing procedures to j determine the cyclic strength of soils, University of Illinois at Chicago Circle for U.S. Nuclear Regulatory 4 Commission, Chicago, IL (1977).
- 20. Roctest, The pressuremeter test: Principles, Testing Equipment and Test Procedure, Roctest, Montreal, Canada (1978).
- 21. Seed, H.B. and Idriss, I.M.,. Soil Modull and Damping Factors f or Dynamic Response Analyses, University of i Calif ornia, Earthquake Engineering Research Center, l
' Report No. EERC 70-10, Berkeley, CA (1970).
i-i e t, 2.6-13 Amendment 23 4 s ,.. .,. ... _ ,,,-.-. -,,.m-m~
S/HNP-PSAR 10/14/82
- 22. Golder Associates, The Southeast Anticline Fault:
Evaluation of Attitude and Displacement, Report prepared f or Washington Public Power Supply System h (1982). 2.6-14 Amendment 28 6.mw o m g- 9 - ~y >
-w-- g--.- 4 , - , - - -
S/HNP-PSAR 10/14/82 APPENDIX 2K GEOPHYSICAL INVESTIGATIONS t UMTANUM RIDGE TO SOUTHEAST ANTICLINE HANFORD SITE, WASHINGTON prepared f or NORTHWEST ENERGY SERVICES COMPANY October, 1981 (Amended October, 1982) gp s-2K-1
/
Amendment 28
S/HNP-PSAR 12/21/811 TABLE OF CONTENTS Page
~ LIST OF TABLES 2K-v LIST OF FIGURES 2K-vi
1.0 INTRODUCTION
2K-1
. l .1 Scope of Investigation 2K-2 1.1.1 Umtanum Ridge-Gable Mountain 2K-2 Area 3.1.2 Central Gable Mountain, DB-10, 2K-2 May Junction Areas 1.1.3 Southeast Anticline 2K-3 2.0
SUMMARY
AND CONCLUSIONS 2K-4 l -
. :2.1 Summary 2K-4
'2.2 Conclusions 2K-4 2.2.1- Gable Butte-Gable Mountain 2K-4 Segment
~ 2.2.1.1 DB-10 Area 2K-4 2.2.1.2 May Junction Monocline 2K-4 2.2.2 Southeast Anticline 2K-4 3.0 GEOLOGIC SETTING 2K-7 4.0 GEOPHYSICAL DATA BASE 2K-9 4.1 Data Acquired for Skagit/Hanford 2K-9 Project 2K-9 4.1.1 Seismic Data 4.1.1.1 Seismic Refraction 2K-9 4.1.1.1.1 Data Acquisition and 2K-9 Processing e 4.1.1.2 Downhole-In-Situ 2K-10 Velocity Measurements . 4.1.1.2.1 Data Acquisition and 2K-10 Processing 4 2K-iii Amendment 23 _ , - . . . . - - - . . . . , .- _ . . . . . . . _ - - .. ,.__,,y- , ._, _. _ _ _ ,
~S/HNP-PSAR 12/21/81 TABLE OF CONTENTS (Cont'd.)
Page 4.1.2 Gravity Data 2K-ll 4.1.2.1 Data Acquisition and 2K-ll Processing 4.1.3 Land Magnetic Data 2K-ll 4.1.3.1 Data Acquisition and 2K-ll , Processing 4.2 Supplemental Geophysical Data 2K-12 4.2.1 Data Supplied by Washington 2K-12 Public Power Supply System 4.2.2 Data Supplied by Rockwell 2K-13 Hanford Operations 5.0 RESULTS OF INVESTIGATIONS 2K-14 5.1 Regional Geophysical Setting 2K-14 5.2 Gable Butte-Gable Mountain Segment 2K-35 5.2.1 Umtanum Ridge to Gable 2K-16 Mountain 5.2.1.1 Introduction 2K-16 5.2.1.2 Discussion of Results 2K-16 5.2.1.2.1 Gravity Data 2K-16 5.2.1.2.2 Land Magnetic Data 2K-17 5.2.1.2.3 Aeromagnetic Data 2K-17 5.2.1.2.4 Seismic Reflection Data 2K-17 5.2.1.3 Interpretation 2K-18 5.2.2 Central Gable Mountain 2K-19 5.2.2.1 Introduction 2K-19 5.2.2.2 Discussion of Results 2K-19 5.2.2.2.1 Land Magnetic Studies 2K-19 5.2.2.2.2 Seismic Refraction Surveys 2K-20 5.2.3 DB-10 Area 2K-22 ! 5.2.3.1 Introduction 2K-22 2K-iv Amendment 23
S/HNP-PSAR 10/14/82-TABLE OF CONTENTS (Cont'd.) Page 5.2.3,2 Discussion of Results 2K-23 5.2.3.2.1 Seismic Data 2K-23 5.2.3.2.2 Gravity Data 2K-24 5.2.3.3 Interpretations 2K-24 5.2.3.4 Summary 2K-26 5.2.4 May Junction Area 2K-26 5.2.4.1 Introduction 2K-26 5.2.4.2 Discussion of Results 2K-27 5.2.4.2.1 Aeromagnetic Data 2K-27 5.2.4.2.2 Gravity Data 2K-27 5.2.4.2.3 Seismic Data 2K-27 5.2.4.3 Interpretation 2K-28 5.3 Southeast Anticline 2K-29 5.3.1 Introduction 2K-29 5.3.2 Discussion of Results 2K-29 5.3.2.1 Magnetic Data 2K-29 5.3.2.2 Gravity Data 2K-30 5.3.2.3 Seismic Refraction Data 2K-30 5.3.3 Interpretation 2K-35 I l% REFERENCES 2K-37 TABLES FIGURES ATTACHMENT 2K-A ATTACHMENT 2K-B ATTACHMENT 2K-C 2K-v Amendmen 28
-. ~. .. .. , __ - _ -. - . -- .-_- . -
S/HNP-PSAR 10/14/82 LIST OF TABLES
- Table No.
2K-1 -Stratigraphic Sections in Test Pits 1 to 7 DB-10 Area.
$8 1
1 i t 4 i l-1 1 d: i-i 2K-vi Amend 28
S/HNP-PSAR 10/14/82 LIST OF FIGURES Figure No. 2K-1 Location Map f or Study Area and Adjacent Physiographic Provinces. 2K-2 Location Map of Structural Elements Within Study Area. 2K-3 Location Map of Seismic Refraction Lines. 2K-4 Seismic Refraction Technique. 2K-5 Downhole Technique. 2K-6 Location Map of Gravity and Land Magnetic Lines. 2K-6A Location Map of Gravity Lines - May Junction 3.% Monocline Area 2K-7 Location Map for Washington Public Power Supply System Aeromagnetic Coverage. 2K-7A Location Map for Washington Public Power Supply I System Gravity Coverage - Southeast Anticline Vicinity of Borehole 125. g 2K-7B Location Map f or Washington Public Power Supply System System Gravity Coverage - Savage Island and Vicinity 2K-8 Location Map f or Rockwell Seismic Reflection and Gravity Data. 2K-9 Pasco-Walla Walla Area Station Location Map. 2K-10 Pasco-Walla Walla Area Total Bouguer Gravity Anomaly Map. 2K-11 Hanford lo Area Station Location Map. 2K-12 Hanford lo Area Total Bouguer Gravity Anomaly , Map. 2K-13 Total Bouguer Gravity Anomaly Map of the Hanf ord Site. 2K-vii Amendmen #28 l _ .. _ . . _ _ _ _.~._. .__ ._ _ _
S/hNP-PSAR 10/14/82 LIST OF FIGURES (Cent'd.) Figure No. 2K-14 Aeromagnetic Map f or the Hanf ord Site. 2K-15 Residual Bouguer Gravity Anomaly Map, Gable Butte-Gable Mountain Segment. 2K-16
~
Plan Map f or Detailed Magnetic Coverage Flanking the Northern Portion of Line 25. 2K-l*- Total Bouguer Gravity Anomaly Map, Umtanum Ridge-Gable Mountain Area. 2K-18 Residual Bouguer Gravity Anomaly Map, Umtanum Ridge-Gable Mountain Area. 2K-19 Simple Bouguer Gravity Anomaly and Ground Surface Profiles, Lines 25 and 23. 2K-20 Land Magnetic Profiles f or the Umtanum Ridge to Gable Mountain Geophysical Program. 2K-21 Land Magnetic Profiles f or Detailed Coverage Flanking Northern Portion of Line 25. 2K-22 Aeromagnetic Map of the Umtanum Ridge to Gable Butte Area. 2K-23 Portion of Processed Reflection Profile f or Rockwell Line 4. 2K-24 Location Map for Central Gable Mountain Land Magnetic Lines. 2K-25 Total Field Contour Map, Land Magnetic Survey, Central Gable Mountain. 2K-26 Location Map for Seismic Refraction Lines, Central Gable Mountain. 2K-27 Isopach Map of Overburden Material, Velocity 3,000 ft/sec. 2K-28 Typical Seismic Cross Section, Central Gable Mountain. 2K-viii
/
Amendment 28
S/HNP-PSAR 10/14/82 LIST OF FIGURES (Cont'd.) Figure No. 2K-29 Seismic Profile Line 9A. 2K-30 Seismic Profile Line 9. 2K-31' Seismic Profile Line 9B. 2K-32 Location Map of DB-10 Area. 2K-33 Detail Location Map of DB-10 Area. 2K-34 Seismic and Gravity Profiles Line DB-10-4. 2K-35 Seismic and Gravity Profiles Line DB-10-8. 2K-36 Seismic and Gravity Profiles Line DB-10-3. 2K-37 Seismic Profile Line 7 and Gravity Profile Line D. 2K-38 Seismic and Gravity Profiles Line 8. 2K-39 Bedrock Contour Map Based on Seismic ' Interpretation, DB-10 Area. 2K-40 Velocity Contour Map for Basalt, DB-10 Area. 2K-41 Total Bouguer Gravity Anomaly Map, DB-10 Area. 2K-42 Residual Bouguer Gravity Anomaly Map, DB-10 Area. 2K-43 Structural Interpretation of Survey Line 8 Based on Drill Hole Data. 2K-44 Cross Section Showing Projection of Upper Fault in DB-10, Striking N30E and Dipping 320W, Based Upon Case 2 Interpretation of Golder Associates (1981). 2K-45 Interpretation of Rockwell Seismic Reflection Line 3-1 by Seismograph Services Corporation. 2K-46 Aeromagnetic Map, May Junction Area. 2K-47 Total Bouguer Gravity Anomaly Map, May Junction Area. 2K-ix Amendme 28
l I S/HNP-PSAR 10/14/82 LIST OF FIGURES (Cont'd.) Figure No. 2K-47A Detailed Total Bouguer Gravity Anomaly Map, May Junction Monocline Area 2K-47B Geologic Model of Gravity Date - Line 8C 2K-48 Bedrock Contour Map Based on Seismic Refraction Data, May Junction Area. 2K-49 Aeromagnetic Map, Southeast Anticline Area. 2K-50 Fence Plots of Land Magnetic Data, Southeast Anticline Area. 2K-50A Contour Map of Land Magnetic Data - Southeast $Y Anticline Vicinity of Borehole 125 2K-51 Total Bouguer Gravity Anomaly Map, Southeast Anticline Area. 2K-51A Residual Bouguer Gravity Anomaly Map - Southeast Anticline Vicinity of Borehole 125. )y 2K-51B Residual Bouguer Gravity Anomaly Map - Savage Island and Vicinity 2K-52 Seismic, Gravity and Land Magnetic Profiles, Line 3. 2K-53 Seismic, Gravity and Land Magnetic Profiles, Line 2. 2K-54 Seismic, Gravity and Land Magnetic Profiles, Line 1. 2K-55 Seismic, Gravity and Land Magnetic Profiles, Line 4A. 2K-56 Seismic, Gravity and Land Magnetic Profiles, Line 4B. 2K-57 -Seismic, Gravity and Land Magnetic Profiles, Line 4C. 2K-58 Seismic, Gravity and Land Magnetic Profiles, Line 6. 2K-x AmendmenY 28
S/HNP-PSAR 10/14/82 LIST OF FIGURES (Cont'd.) Figure No. 1 2K-59 Seismic, Gravity and Land Magnetic Profiles, Line 6A. 2K-60 Seismic and Gravity Profiles, Line 6B.
-2K-61 Bedrock Contour Map Based on Seismic Refraction, Southeast Anticline.
/
2K-xi J' Amendment 28 _ - __. ._ .. _ _. _ , _ . . . _ . ~ . _ - . . . . . . ,
S/HNP-PSAR 10/14/82
1.0 INTRODUCTION
As part of the investigations of the Umtanum Ridge-Gable Mountain structural trend, geophysical field studies were conducted for Northwest Energy Services Company (NESCO) from February 1980 to June 1981. The geophysical investigations were part of the overall siting study for the Skagit/Hanford Project. Amendment 28 updates Appendix 2K to reflect additional investigations conducted on the gg Southeast atnicline by the Supply System and the May Junction monocline by NESCO during 1982. The geophysical investigation focused primarily on the bedrock configuration of the Hanford Site (Figure 2K-1). This report describes the geophysical investigations of the Umtanum Ridge-Gable Mountain structural trend, its associated structures, Gable Butte and Gable Mountain, and a buried ridge, informally named the Southeast Anticline, trending southeasterly f rom Gable Mountain. The present area of study covers nearly 200 square miles of the Hanford Site, which is located in the central portion of the Yakima Fold Belt of the central Columbia Plateau of south-central Washington (Figure 2K-1). The bedrock units, the Miocene Columbia River Basalt Group, are overlain by as much as 700 f eet of Late Tertiary and Quarternary sediments and sedimentary rocks. The drilling performed by Golder Associates encountered the Elephant Mountain Member of the Saddle Mountains Basalt as the youngest bedrock unit in all boreholes. Consequently, the top of bedrock can be considered a structural surface on the top of the Elephant Mountain Member, except south of Vernita Bridge, where the Elephant Mountain Member is not present (Figure 2K-2); the older Pomona Member is the uppermost basalt unit in this area. These geologic conditions are favorable for the geophysical investigation of subsurf ace structure. The density contrast between the sediments and the basalt is 0.3-0.7 g/cm3 The Bouguer gravity anomaly map for the Hanford Site is an approximate structural contour map with an arbitrary datum and a conversion factor of 150 feet of basalt elevation per 1 milligal of gravity relief. The conversion factor was determined from comparison of the profile of top of basalt (based on logging of drillholes and analysis of cuttings and core) with the gravity anomaly along the same profile. ; .If no erosion of the Elephant Mountain basalt has occurred, , then the top of basalt is a structural surface. However, some erosion has occurred. On the basis of the measured I thickness of the Elephant Mountain basalt in all holes that extended through the unit, the erosion has removed .dif f erentially at most 80 f eet of basalt. Therefore, the <*S f L top of basalt is a structural surface within +40 feet f(gy 2K-1 Amendment 28 i _ . , - , - ~ - - . . . . , , ..
S/HNP-PSAR; 12/21/81 l (except in the area of Vernita Bridge where the unit is~not l present). l The conversion. factor of 150 feet = 1 milligal is the average value determined for several profiles. It varies by approximately 20% over the study area as a result of the variation of the density of'the Ringold Formation, which in Lturn is-controlled by the relative thickness of coarse and fine units. 1.1 SCOPE OF INVESTIGATION The geophysical' investigations of the Umtanum Ridge-Gable Mountain structural trend were designed to delineate bedrock topography and examine specific structures within . . .each. area described below and shown-on Figure 2K-2. 1.1.1 - Umtanum Ridge-Gable Mountain Area The Umtanum-Ridge-Gable Mountain geophysical studies were designed.to determine the structural continuity or 1 discontinuity between Umtanum Ridge and Gable Mountain. Aeromagnetic and gravity data acquired for the Washington 4 Public Power Supply System by Aeroservice, Inc. and Weston Geophysical Corporation, respectively, were interpreted by Weston Geophysical Corporation (1978a, 1978b, 1978c, Washington Public Power, 1977) as indicating possible structural continuity from Umtanum Ridge to Gable Mountain. Myers and-Price (1979) concluded that the Gable Butte structure was a second-order fold on a continuous, primary fold linking Gable Mountain with Umtanum Ridge. Accordingly, gravity and land magnetic data were arquired and interpreted in order to analyze and characterize the structural continuity or discontinuity of the Umtanum Ridge to Gable Mountain trend. 1.1.2 Central Gable Mountain, DB-10, May Junction Areas The Central Gable Mountain-DB-10 area was investig'ated to determine the structural relationships between this area and the Umtanum ridge structure as well as to augment
. geologic investigations of faulting.. Corehole DB-10 encountered two zones of reverse faulting with a combined offset estimated to be 160 feet (Myers and Price, 1979).
Weston Geophysical conducted a program of seismic I l 2K-2 Amendment 23
S/HNP-PSAR 12/21/81 refraction, gravity and land magnetics to complement the geological studies of the faults. l Geophysical data were acquired on Gable Mountain to assist in the: investigation of faults in the central Gable Mountain area. The geophysical program of seismic , refraction, gravity.and land magnetics was designed to assist in tracing the faults, as well as to investigate features believed related to the observed offset. Seismic. refraction data were also utilized in feasibility studies for various trench localities on Gable Mountain. I The May Junction linear, initially defined on the basis of aeromagnetic-data (Myers and Price, 1979), was investigated by seismic refraction and gravity data acquired by Weston Geophysical and drilling data collected by Golder Associates to characterize the structural relationships between this feature and the Umtanum Ridge-Gable Mountain structural trend. 1.1.3 Southeast Anticline ir i The third major area of investigation was the subsurface ridge informally named the Southeast Anticline. The aeromagnetic data acquired by Washington Public Power
- , Supply System shows a magnetic high trending southeasterly from the eastern end of Gable Mountain. Extensive seismic refraction, gravity and land magnetic data were acquired and interpreted in order to characterize the Southeast
. Anticline and the structural relationships between the l-Southeast Anticline and the first , second , and third-order folds of the Umtanum Ridge-Gable Mountain structural
- j. trend.
L i J t r i 2K-3 Amendment 23
S/HNP-PSAR 10/14/82 2.0
SUMMARY
AND CONCLUSIONS 2.1
SUMMARY
The results of the geophysical investigation implemented by Weston Geophysical f or the Skagit/Hanford Project characterize the subsurface basalt topography of the Hanford Site. The basalt surface, based on geologic information, can be considered a structural surface, except in the area south of Vernita Bridge. New geophysical data obtained for the Skagit/Hanford Project consist of approximately 10,700 closely spaced, i 3g surveyed, and high precision gravity stations; 500 line miles of land magnetic profiles; and 72 line miles of seismic refraction profiles. Previously acquired data utilized in this study include aeromagnetic data, gravity data, and seismic ref raction data collected f or Washington Public Power Supply System, as well as aeromagnetic data, gravity data, and seismic reflection data acquired by Rockwell Hanf ord Operations. Two principal structural features have been delineated by the geophysical investigations, the Gable Butte-Gable Mountain segment of the Umtanum Ridge-Gable Mountain structural trend and the Southeast Anticline. The Gable Butte-Gable Mountain segment of the Umtanum Ridge-Gable Mountain structural trend, is a broad, low amplitude anticline within the Hanford Site and is bounded on the , east by the May Junction monocline. The various faults reported on Gable Mountain and in DB-10 are features within . the Gable Butte-Gable Mountain segment. A subsurface, bedrock ridge, the Southeast Anticline, has been defined as an 8-mile long, low amplitude anticlinal fold. The Southeast Anticline is separate from and extends 1 mile to the northwest of the eastern end of the Gable Mountain portion of the Gable Butte-Gable Mountain segment.
2.2 CONCLUSION
S 2.2.1 GABLE BUTTE-GABLE MOUNTAIN SEGMENT I The gravity anomaly associated with the Gable Butte-Gable Mountain segment of the Umtanum Ridge-Gable Mountain structural trend is a 5 milligal gravity high extending from the eastern end of Umtanum Ridge to the May Junction ,9 2K-4 Amendmet 28
-- W - - w w w ww-r **
4 T e- -T
S/HNP-PSAR 10/14/82 monocline. The Gable Butte-Gable Mountain segment, defined primarily by gravity data, is a segment of the Umtanum Ridge-Gable Mountain structural trend, although indicative of a change in structural style from the single anticlinal ridge of Umtanum Ridge to the broad, first-order fold with superimposed, second-order anticlines of the Gable Butte-Gable Mountain segment. This change in structural style occurs at the eastern end of Umtanum Ridge south of Vernita Bridge. The broad, first-order antif orm is bounded on the east by the monoclinal flexure resulting in the May Junction linear. 2.2.1.1 DB-10 Area The gravity and seismic refraction data are consistent with the geologic interpretation (Golder Associates, 1981, Figure 20-69) that the upper DB-10 fault strikes north-south and dips 300 to the west. Based on seismic refraction velocity data, the length of the upper DB-10 fault appears to be 2,400 feet, limiting
- the fault to the small, northwest-trending, anticlinal fold south of Gable Mountain.
2.2.1.2 May Junction Monocline The May Junction monocline trends north-south for a distance of 21/2 miles f rom the eastern end of Gable Mountain, has a maximum relief of 300 feet, and a maximum dip on the eastward sloping rock surface of 100 An l bg elongate gravity high indicative of an anticlinal fold l extends across the southern portion of the May Junction monocline. The seismic refraction data for the May Junction and DB-10 areas indicate an anisotropic condition in the basalt. The bedrock velocities are higher in a north-south direction than in an east-west direction. The anisotropy suggests that fracturing is oriented north-south, parallel to the May Junction monocline. 2.2.2 SOUTHEAST ANTICLINE i The Southeast Anticine is a seasrate structure f rom the , first-order fold of the Gable butte-Gable Mountain segment. The Southeast Anticline is also separate from the second-d% 2K-5 Amendment 28
S/HNP-PSAR 10/14/82 l i 1 order fold,. Gable Mountain, and extends l' mile to the northwest beyond the eastern end of Gable Mountain. The. trend of the Southeast Anticline changes from northwest
' to east-northeast at its southeastern end and does not extend east of the Columbia River. db 4
i . J v 2K-6 Amendment 28
/
S/HNP-PSAR 12/21/81 t 3.0 GEOLOGIC SETTING
-The study area is located in south-central Washington, within the central Columbia Plateau. The geophysical data were acquired primarily within the Hanford Site, which is situated in the central Pasco Basin. The underlying bedrock in the area of investigation is composed of the Columbia River Basalt Group. With the exception of several exposures of basalt ranging up to 600 feet in relief, the study area is underlain by as much as 700 feet of Late Tertiary and Quarternary alluvial and windblown sediments and sedimentary rocks.
The exposed basalts and those immediately underlying the overburden in the study area are members of the late Miocene Saddle Mountcins Basalt of the Columbia River Basalt Group. The basalt is overlain by a Miocene to Pliocene series of alluvial sediments and sedimentary rocks composed of fanglomerates, poorly to well consolidated conglomerates, silts, sands and clays assigned to the Ringold Formation, whose type section is located within the area of investigation. The Ringold sediments are overlain by two sets of gravel units which are of glacial flood origin. The older set, immediately overlying the Ringold Formation, has been termed the pre-Missoula gravels. Although the pre-Missoula gravels within the study area have not been dated, possibly correlative gravels have been dated elsewhere as approximately 200,000 years old (Tallman, et al., 1978). The pre-Missoula gravels are overlain by the Missoula flood gravels which have been dated as young as 13,000 years old (Mullineaux, et al., 1977). The Missoula gravels in the study area are overlain by a veneer of loess and windblown sand. The Hanford Site is located within the central and eastern portion of the Yakima Fold Belt, a series of linear and curvilinear anticlinal ridges which extends from the Cascade Mountains, 70 miles to the west, to an area east of the Columbia River, approximately 40 miles to the southeast. The anticlinal ridges and the broad, intervening synclines are all composed of Columbia River Basalts and the interbeds of the Ellensburg Formation. The ridges are generally asymmetric and trend from east-west to N600W. Umtanum Ridge and lakima Ridge plunge beneath the alluvial sediments at the western margin of the Hanford Site while the Rattlesnake Hills change trend and form the southwestern boundary of the Hanford Site. Gable Butte and Gable Mountain, subsidiary structures superimposed upon the Umtanum Ridge-Gable Mountain structural trend, are the only outcropping folds of the 2K-7 Amendment 23
S/HNP-PSAR 12/21/81 Yakima Fold Belt within the area of investigation. j Information based upon drilling data acquired within the
; Hanford; Site by Golder Associates.(Appendix 2R) and Rockwell Hanford Operations (Myers and Price, 1979, Figure III-25e) indicates that the Elephant Mountain Member of the ,
Saddle 'iountains Basalt is the uppermost basalt unit within r most of the area of investigation. Therefore, in the areas where the Elephant Mountain Member is the uppermost basalt unit, the bedrock surface is essentially a structural surface. l l l i 2K-8 Amendment 23
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S/HNP-PSAR 12/21/81 4.0 GEOPHYSICAL DATA BASE 4.1 DATA ACQUIRED FOR SKAGIT/HANFORD PROJECT Seismic, gravity and land magnetic data were acquired for the Skagit/Hanford Project along surveyed traverse lines; horizontal and vertical survey control were established to the nearest 0.1 foot. 4.1.1 SEISMIC DATA 4.1.1.1 Seismic Refraction Approximately 72 miles of seismic refraction data were acquired along the profile lines shown on Figure 2K-3. The seismic refraction method is utilized to determine the depth to a refracting horizon and the thickness of major seismic strata overlying a high-velocity refracting horizon. Interpretations are based on the measurement of the time required for elastic waves, generated at a point source, to travel to a series of geophones spaced at known intervals on the ground surface. Depth computations are based on the ratio of the velocities and the horizontal distance from the shot point where the refracted wave overtakes the direct wave (Figure 2K-4). Seismic refraction is preferred over seismic reflection because the refraction technique is a direct measurement of the variable depth to bedrock and the highly variable near surface velocities. The variations in velocity and depth must be known in order to reasonably interpret any seismic reflection data.
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4.1.1.'l.l' Data Acquisition and Processing ~ Seismograms were obtained using a portable 24-trace seismograph system which allowed direct reading of seismic wave arrivals to 1 millisecond. Continuous profiling was accomplished by having the end shotpoint of one spread coincident with the end or intermediate position shotpoint of the succeeding spread. The near-surface low velocity material and the underlying 6,000-10,000 ft/sec. refractor which occurs extensively throughout the project area were profiled using seismic spreads, generally of 800 feet in length and overlapped 2K-9 Amendment 23 _ _ _ ~,
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.every,400 feet. This allowed continuous _ datum control.of a i
- higher 1 velocity refractor which generally occurs between i elevations'350 and 400 feet above-sea-level.
Bob profiling the basalt, shotholes were drilled to depths 5 to:200 feet; detectors were spaced at 100-foot of .0 ! intervals touform 2,300-foot seismic spreads (see Figure 2K-4). _ Seismic energy for end.and offset' shots was i generated with 50 to 200 pounds of dynamite placed below the' water table for efficient energy generation. . !
, Corrections were made for the near-surface low velocity material overlying the 6,000-10,000 ft/sec. refractor._ !
. This refractor provided a datum for reducing the deep refraction data using delay-time interpretation 1 techniques ,
, described by _ Gardner . (1967) . The. absolute delay times '
_ calculated from shallow refraction profiling were 1
. subtracted-from the intercept values calculated from deep refraction.- After_ applying this datum correction, a shothole correction was also applied to account for any , . variations in the depth of the shotholes with respect to ,
t' the datum.. Lines of best fit were placed through the , corrected intercept values-to form a continuous relative-
. set of data from both directions along the seismic line.
From the relative curves, an average curve was constructed I from which the absoluto delay times were calculated. Delay !- . times were-converted to depths to the 16,000 ft/sec. basalt refractor using an average velocity as determined by downhole velocity measurements. 4.1.1.2 Downhole-In-Situ Velocity Measurements
.Since previous seismic studies in the H'anford Site (Washington.Public Power. Supply System, 1974) indicated at least one velocity inversion within the overburden i
material, downhole measurements were made in the overburden from the top of the near-surface high velocity refractor to approximately the top of basalt. The downhole velocity data were_used to process the delay-time refraction data and obtain a profile.of the top of Gasalt.- Measurements ' 'were made -in 52 boreholes within the study area (Figure 2K-3). 4.1.1.2.1 Data-Acquisition-and Processing , In'the downhole.techni'que, the seismic energy, generated by J explosivesLin an adjacent shallow borehole (generally.50 ; feetLin depth) is= received byo24 geophones spaced at 10- ! 2K-10 Amendment 23 - l
S/HNP-PSAR 10/14/82 foot intervals in the monitoring hole (Figure 2K-5). Typically, multiple shots were used and the cable adjusted (overlapped) to obtain data at 5-foot intervals to various depths (usually the top of basalt) . The downhole data f or each borehole were computer processed and an average velocity value determined f or the overburden column. Time-distance plots of the data were also constructed in order to define the velocity interf aces. The downhole velocity data in profile f orm is presented in Attachment A. The average velocities determined from downhole along a given seismic line were then used to convert the time profile of the 16,000 f t/sec. ref ractor to a depth profile (Section 4.1.1.1.1). 4.1.2 GRAVITY DATA 4.1.2.1 Data Acquisition and Processing Approximately 10,700 gravity stations were established l along traverse lines within the Hanford Site at the locations shown on Figure 2K-6. All data points were acquired utilizing Lacoste-Romberg Model G gravimeters, capable of 0.01 milligal reading precision. All gravity measurements were made in reference to local base stations established from the Washington gravity base station network (Pasco B Station, Nilson, 1976). The gravity data were generally acquired at a 400-foot station interval along the traverse lines (Figure 2K-6). In areas where greater detail was required to more closely determine the location of a causative feature for an anomaly, additional stations were established at a 100-foot interval. Additional gravity stations were also established in Sections 32 and 33 of T13N, R27E, approxi-mately one mile south of Gable Mountain (Figure 2K-6A) to investigate the May Junction monocline. The stations were >9 located along eleven traverse lines (8A-8N, 8J and portions of Lines 8 and D) at 100-foot intervals. Gravimeter dial readings were converted to milligal values utilizing conversion factors appropriate to the instrument (supplied by the manufacturer). The data were corrected for instrumental and tidal drift by means of base station reoccupations at intervals of three hours or less. The drif t was considered linear over this time period. 2K-11 Amendme 28
S/HNP-PSAR 10/14/82 Subsequent to correcting the gravity observations for instrumental and tidal drif t, the data were corrected for latitude as well as station elevation and assumed rock density (combined f ree air and Bouguer corrections) . The gravity data were all reduced to a datum elevation of sea
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S/HNP-PSAR 12/21/81 level utilizing a density of 2.67 g/cm3 The resulting simple Bouguer gravity values, in the vicinity of Gable Mountain and Umtanum Ridge, were individually corrected for the surrounding variations in terrain according to Hammer (1939) and Douglas'and Prahl (1971). The effects of variations in the terrain within a 13.6 mile radius were applied to each station in these two localities. The resultant gravity data points were then processed and contoured to. produce total, regional and residual Bouguer anomaly maps.
- 4.1.3 LAND MAGNETIC DATA 4.1.3.1 Data Acquisition and Processing Land magnetic data were acquired along five hundred miles of traverse lines during this investigation. All data were acquired utilizing proton precession magnetometers and were recorded to the 1.0 gamma reading accuracy of the instruments. Local base rtations were used for standard closure procedures to monitor the diurnal variations of the earth's magnetic field.
The magnetic data were acquired at 100-foot intervals for one-quarter to one-third of the data collected along the lines illustrated in Figure 2K-6. The remaining data were acquired at 50-foot intervals. Subsequent to correcting the diurnal drif t, the data for each line were plotted in profile form and evaluated collectively with the seismic refraction and the gravity data for the same line. 4.2 SUPPLEMENTAL GEOPHYSICAL DATA 4.2.1 DATA SUPPLIED BY WASHINGTON PUBLIC POWER SUPPLY SYSTEM The Washington Public Power Supply System provided gravity, land magnetic, aeromagnetic and seismic refraction data to augment the data acquired for Northwest Energy Services j Company. The Supply System data were used to assist in 1 planning of the NESCO programs as well as combined with NESCO data to increase the data base available for interpretation. 2K-12 Amendment 23 l _ . ._ _ _ _ . . - . _ . - - _ . ~ . . - ~ - _ . - - .. - . a
S/HNP-PSAR 10/14/82 The interpretations by Weston Geophysical (Weston Geophysical, 1978c; Washington Public Power Supply System, 1977, Appendix 2R-I) of both the gravity and land magnetic data provided guidelines for new programs. The aeromagnetic data acquired by the Supply System (Figure 2K-7) were also utilized in the geophysical investigation of the Hanf ord Site. Details of the aeromagnetic survey, as well as previous interpretations, can be found in Washington Public Power Supply System (1977, Appendix 2R-I) and Weston Geophysical (1978a). Seismic refraction data collected by Weston Geophysical in the vicinity of the Supply System sites (Washington Public Power Supply System, 1974) provided guidelines f or data acquisition and processing techniques, as well as additional input concerning the seismic characteristics of the overburden of the Hanford Site. Additional gravity and magnetic data in the vicinity of Line 4A (Figure 2K-7A) and gravity data on Savage Isla.id and east of the Columbia River (Figure 2K-7B) acquired f or bg the Supply System (Weston Geophysical, 1982) supplemented the NESCO data base f or f urther evaluation of the Southeast anticline. l 4.2.2 DATA SUPPLIED BY ROCKWELL HANFORD OPERATIONS Rockwell Hanford Operations provided land magnetic and gravity data, aeromagnetic contour maps of a multi-level survey, and prints of processed reflection data. These data, acquired during Rockwell's siting program f or a nuclear waste repository, were utilized in program planning and were evaluated relative to the data obtained for the Skagit/Hanford Project. The locations of the Rockwell reflection profiles and those Rockwell gravity data utilized in this study are shown on Figure 2K-8.
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S/HNP-PSAR 12/21/81 5.0 RESULTS OF INVESTIGATIONS 5.1 REGIONAL GEOPHYSICAL SETTING l The Central' Columbia Plateau of south-central Washington < has been. studied extensively during the past five to ten years. A large volume of geophysical data has been acquired by the United States Geological Survey (Swanson, et al. ,1979 and Zietz, et al. ,1971) , by Rockwell Hanford Operations in their siting program for a waste repository (Myers and Price, 1979, and others), by various consultants to Washington Public Power Supply System (Weston Geophysical, 1978a; 1978b; 1978c; Fashington Public Power Supply System, 1981, 1977) - and through the present investigations for NESCO. The gravity map for the Central Columbia Plateau (Figures 2K-9 and 2K-10) defines a north-northeast trending, semi-rectangular gravity high with two " lobes" extending from its southeastern and southwestern extremities. The rectangular high has been interpreted as defining a thick section of relatively high density material. The lower, high density body underlies 1-2 kilometers of Columbia River Basalts and has been modeled at 3-5 kilometers thick. The sides of the lower body dip inward at slopes ranging from 50-450 (Washington Public Power Supply System, 1981, Appendix 2.5L). The present study area is located over the central portion of the rectangular high and is underlain by 5-7 kilometers of basalt and probable basaltic material. The generalized configuration of the subsurface basalt topography of the Hanford Site is depicted on the Hanford 10 gravity map (Figure 2K-12) . The Gable Butte-Gable Mountain segment of the Umtanum Ridge-Gable Mountain structural trend is indicated by an elongate, 5 milligal gravity high trending N750W, north of the Skagit/Hanford site. Interpretations of aeromagnetic data for the Columbia Plateau also indicate an excess thickness of dense, magnetic rocks beneath the plateau. Zietz et al. (1971) interpreted a high-level-(15,000 feet above sea level) survey and postulated the thickest section of basalt as underlying the region along the eastern margin of the Hanford Site. The interpretations of low-level surveys (Washington Public Power Supply System, 1977, Appendix 2R-I; Swanson et al., 1979; Weston Geophysical, 1978a) have characterized the prominent anticlinal ridges of the Yakima Fold Belt and defined the subsurface extensions of these ridges within the Hanford Site. Swanson et al. (1979) 2K-14 Amendment 23
S/HNP-PSAR 12/21/81 postulated the existence of a dike swarm in the area east of the Hanford Sit,e. Two principal structural features, the Gable Butte-Gable Mountain segment and Southeast Anticline, have been delineated by the geophysical investigations for the Skagit/Hanford Project. These featUses are also in the aeromagnetic _ data provided by Washington Public Power Supply System (Figure 2K-14). Additional subsurface basalt highs, indicated by both gravity and aeromagnetic data, are located in the western and southwestern portion of the Hanford Site. 5.2 GABLE BUTTE-GABLE MOUNTAIN SEGMENT The Gable Butte-Gable Mountain segment, defined by both gravity and magnetic data, extends from the eastern portion of Umtanum Ridge to the eastern end of Gable Mountain (Figures 2K-13 and 2K-14). The east-west trending northern edge of the Gable Butte-Gable Mountain segment, is defined by a steep, linear gravity gradient (Figure 2K-15), which merges with the northern end of the May Junction linear at the eastern end of Gable Mountain. The eastern boundary of the first order antiform of the Gable Butte-Gable Mountain segment, defined by the May Junction monocline, trends 2h miles southward from the eastern end of Gable Mountain. An elongate gravity high indicative of a small anticlinal fold extends across the southern portion of the May Junction monocline. The southern flank of the gravity high associated with the Gable Butte-Gable Mountain segment trends N650-750W from the southern end of the May Junction monocline; the gradients along the southern flank are not as steep as the northern or eastern flanks. The aeromagnetic data in the vicinity of the Gable Butte-Gable Mountain segment exhibit characteristics similar to the gravity data (Figure 2K-14). The northern flank is defined by a magnetic low, the eastern boundary by the May Jun : tion Linear (in Myers and Price, 1979). The internal components of the magnetically defined Gable Butte-Gable Mountain segment are zones of high frequency anomalies grouped in an er. echelon pattern. The western portion of the Gable Butte-Gable Mountain segment is intersected by the Juniper Springs and Nancy lineaments (Washington Public Power, 1977, Appendix 2R-I; Weston Geophysical, 1978a). The overall Gable Butte-Gable Mountain segment is characterized'as a broad, low amplitude, east-west 2K-15 Amendment 23
S/HNP-PSAR 12/21/81 trending, asymmetric antiform with internal features trending N650-750W and is bounded on the east by the May Junction monocline. The reflection data acquired by Rockwell Hanford Operations also indicate an asymmetry with bedrock slopes of up to 400 on the northern flank and up to 50 on the southern flank. The major components of the Gable Butte-Gable Mountain segment are discussed in Section 5.2.1 through Section 5.2.4. 5.2.1 UMTANUM RIDGE 10 GABLE MOUNTAIN 5.2.1.1 Introduction Gravity and ground magnetics were the geophysical techniques employed in the field investigation of the region between Umtanum Ridge and Gable Mountain. The gravity data were collected at 400-foot intervals along all profiles (Figure 2K-6) and at 100-foot intervals along selected portions of Lines 23 and 25 for additional detail over specific features discovered during this study. The ground magnetic data were acquired at 50-foot intervals along all gravity lines, as well as along four shorter lines flanking the northern portion of Line 25 (Figure 2K-16). In addition to the new geophysical data, the Washington Public Power Supply System's aeromagnetic data and Rockwell reflection data were analyzed. 5.2.1.2 Discussion of Results 5.2.1.2.1 Gravity Data The Bouguer anomaly map depicting the configuration of the basalt topography is shown on Figure 2K-17. The gravity data for Lines 25-31 near the eastern end of Umtanum Ridge have been terrain-corrected. The Bouguer anomaly map o' the Umtanum Ridge to Gable Mountain area is characterized by several obvious features; the most prominent is an east-west trending, linear gradient. The steepest portions of the gradient, along Lines 13, 17, 19, and 21, result from bedrock relief of approximately 500 feet (utilizing a conversion of 150 feet /milligal) on a slope which dips 200 to the north. l A smaller east-west feature, not evident in the contour map as the amplitude of the anomaly is less than the contour 2K-16 Amendment 23
S/HNP-PSAR 12/21/81 interval, occurs within the prominent east-west trending gradient. This gravity high is present on Lines 23 and 25 (Figure 2K-19) at the location shown on Figure 2K-16. A positive bedrock feature of erosional or structural origin on the northward sloping surface would produce this anomaly. 5.2.1.2.2 Land Magnetic Data The land magnetic data indicate features very similar to those seen in the gravity data. The northern flank is characterized by magnetic anomalies exceeding 1500 gammas (Figure 2K-20). The higher frequency anomalies along the northern portions of Lines 23 and 25 coincide with gravity anomalies on the same lines (Figure 2K-19). Four short magnetic lines were acquired in the area flanking Line 25 (Figure 2K-16) and indicate that the causative feature is continuous for approximately 2 miles (Figure 2K-21). 5.2.1.2.3 Aeromagnetic Data The aeromagnetic data provided by Washington Public Power Supply System show features similar to those indicated by the gravity and land magnetic data. A continuous, magnetic low extends eastward from the Umtanum Ridge area to the Gable Mountain area (Figure 2K-22) and corresponds spatially to the linear gravity gradient coincident with the northern flank of the Gable Butte-Gable Mountain segment. The aeromagnetic pattern of the Gable Butte-Gable Mountain area consists of numerous, high-frequency anomalies at a relatively higher intensity than surrounding areas. The northwesterly-trending regional aeromagnetic lineaments, Juniper Springs and Nancy (Weston Geophysical, 1978a; Washington Public Power, 1977, Appendix 2R-I) cross the Umtanum Ridge-Gable Mountain structural trend between Umtanum Ridge and the Gable Butte. 5.2.1.2.4 Seismic Reflection Data Lines 4 and 5 of the seismic reflection survey (Figure 2K-8) performed by Seismograph Service Corporation for Rockwell Hanford Operations are located across the Gable Butte-Gable Mountain segment of the Umtanum Ridge-Gable ' Mountain structural trend. Line 5 is a north-south line coincident with gravity Line 21. Line 4 runs north toward Gable Butte, then northeasterly to the Columbia River along 2K-17 Amendment 23
S/HNP-PSAR 12/21/81 Line llA,. passing between Gable Butte and the west end of I Gable Mountain. l The reflecting horizons as interpreted qualitatively (Figure 2K-23) dip approximately 260 to the north along Line 4. When projected perpendicular to the anomaly, the dip is approximately 390 The reflecting horizons on Line 5 are discontinuous, therefore the dip could not be determined. 5.2.1.3 Interpretation The northern flanks of the Umtanum Ridge and Gable Butte-Gable Mountain segments are colinear, as defined by the geophysical data. The asymmetric gravity and magnetic highs associated with Umtanum Ridge trend east-west. The Gable Butte-Gable Mountain segment is a broad, low amplitude, east-west trending, asymmetric antiform with internal features trending N600-750W. The geophysical data are interpreted as indicating a change in style of folding from a single anticlinal structure along Umtanum Ridge to a broad, low-amplitude anticlinal high with smaller en echelon anticlines superimposed in the Gable Butte and Gable Mountain area. The structural style changes in the area where the Juniper Springs and Nancy magnetic linears intersect the Umtanum Ridge structure. The Juniper Springs linear has been interpreted as indicative of a fault (Washington Public Power Supply System, 1977, Appendix 2R-I) which is younger than Umtanum Ridge. The Nancy linear (Weston Geophysical, 1978a), at the intersection of the Umtanum Ridge ' ble Mountain structural trend, is nearly coincident wa h the interpreted subcrop limit of the Elephant Mountain Basalt as defined by Myers and Price (1979) (Figure 2K-2). Since the Elephant Mountain Basalt is absent in the area south of Vernita Bridge, the gravity anomaly map of this area cannot strictly be considered a structural contour map. Therefore the western boundary of the Gable Butte-Gable Mountain segment is only broadly defined by the geophysical data. 2K-18 Amendment 23
S/HNP-PSAR 12/21/81 5.2.2 CENTRAL GABLE MOUNTAIN 5.2.2.1 Intreduction Geophysical studies on Gable Mountain consisted of ground magnetics and seismic studies in support of Golder Associates' investigations of the central Gable Mountain fault and possible " pull-apart" features. Ground magnetic studies were performed for the purpose of general characterization of the central Gable Mountain area. Seismic refraction studies were conducted to determine depths to bedrock for planning exploration trenches and to investigate the " pull-apart" feature on the high bluff to the southeast of the central Gable Mountain fault. Other seismic profiles were located to characterize the subsurface conditions within the saddle between the east and west anticlines on Gable Mountain. 5.2.2.2 Discussion of Results 5.2.2.2.1 Land Magnetic Studies The locations of land magnetic profile lines on Gable Mountain are shown on Figure 2K-24 and the contour map of the total magnetic field is shown on Figure 2K-25. Significant features of the contour map are:
- a. A linear east-west magnetic high G-1 to the west of the central Gable Mountain area. This high has steep gradients on both its north and south sides.
-b. A northeast-trending magnetic feature G-2 in the approximate position of the scarp which forms the southeast side of the central Gable Mountain fault.
- c. A magnetic high G-3 located on the south side of Gable Mountain on the saddle between the east and west anticlines on Gable Mountain.
- d. The flank G-4 of a magnetic high located on the south side of Gable Mountain extending easterly from the magnetic high G-3.
There is no unique interpretation associated with these magnetic features; however, they are important geophysical data which serve to constrain geologic interpretations of 2K-19 Amendment 23
S/HNP-PSAR 12/21/81 the observed structural features on Gable Mountain. Magnetic gradients and trends G-1, G-2, and G-4 are indicative of structural features or associated with bedrock topographic features such as a scarp. Geologic structural features which would cross these gradients would disrupt, offset, or in some way alter the magnetic contour patterns observed. In that manner, the geologic ' interpretation of larger structural features is constrained; it is recognized, of course, that small geologic features could be present and not be detected with the present grid spacing. The magnetic high G-1 is coincident with the west anticline of Gable Mountain as mapped by Golder Associates (1981, Figures 20-51). The magnetic gradient G-2 is related to basalt topography, specifically the edge effect of the northeasterly-trending basalt ridge on he eastern side of the saddle which overlies the central Gable Mountain fault. The trend of this magnetic feature, G-2, becomes more easterly and is no longer parallel to the scarp in the vicinity of Line GM-1. Seismic data in this area also show that the shallow high velocity basalt trends easterly in this area (the weathered basalt thickness increases), further supporting the interpretation that the magnetic gradient is related to basalt topography. The magnetic high G-3 may be indicative of a basalt high. The magnetic feature G-4 extending easterly from the , magnetic high G-3 appears to be indicative of bedrock topography, although a structural interpretation such as the edge of a fold is also permissible. 5.2.2.2.2 Seismic Refraction Surveys The locations of seismic refraction profile lines in the central Gable Mountain area are shown on Figure 2K-26. Profiles for those seismic lines not individually discussed in this section are included in Attachment B. Seismic refraction surveys were initially conducted on Gable Mountain to determine the thickness of unconsolidated overburden materials above the bedrock at proposed trenching locations. As shown on the isopach map, l'igure 2K-27, the thickness of the low velocity overburden material (less than 3,000 ft/sec.) increases in a southwesterly direction along the trend of the central Gable Mountain fault. A typical cross-section profile across this trend is shown on Figure 2K-28. Toward the northeast, where the loose overburden material is not 2K-20 Amendment 23
S/HNP-PSAR 12/21/81 present, seismic velocities of approximately 6,000 ft/sec. were detected in the immediate vicinity of the fault zone. This velocity value is typical of the fractured rock that was excavated in the exploration trenches. Toward the southwest, the relatively narrow zone of 6,000 ft/sec. ' material becomes more difficult to define because of the increasing thickness of the overlying low velocity
- 3. materials (see Profile Line 9A, Figure 2K-29). Thus a definitive tracing of the fault zone by seismic refraction techniques is not possible.
Other seismic refraction profiles were located in the saddle area between the east and west anticlines on Gable Mountain to obtain general subsurface information for planning trenching and drilling activities. In the northwestern region, a relatively extensive area and thickness (up to 80 feet) of 7,000 to 8,000 ft/sec. material was detected on Line 9 (Figure 2K-30). Golder Associates identified the material encountered in Borehole 107 along Line 9 as weathered and broken basalt. Toward the southern part of the saddle, the thickness of the loose low velocity overburden material increases I substantially (see Figure 2K-31, Profile for Line 9B and Figure 2K-27) . Seismic refraction lines in the vicinity of the trenches which cross the South fault define a locally shallow ridge of 6,000 ft/sec. material. Several seismic refraction lines were located southeast of the central Gable Mountain fault to investigate the hypothesis that the offset on the Central Gable Mountain fault was due to a nontectonic mechanism. The seismic lines were located across the postulated " pull-apart" feature, the head scarp of a possible gravity slide feature. The typical Gable Mountain cross section (Figure 2K-28) shows that the basalts which outcrop throughout much of this area have near-surface velocities of 8,000 to 11,000 ft/sec. However, in the vicinity of the " pull-apart" feature between Stations 10+00 and 14+00 (Figure 2K-
- 28) lower velocity materials are present; these velocities i are 4,000 to 6,000.ft/sec. and have been identified by
- trenching as fractured and weathered basalt material.
Although the geophysical data on Lines LS-1, LS-2, and LS-3 l do not exhibit any specific feature which can be directly associated with the suggested " pull-apart", there is a generalized spatial correlation between these lower velocities and the suggested location of the " pull-apart" feature. 2K-21 Amendment 23
S/HNP-PSAR.. 12/21/81 l I 5.2.3 DB-10 AREA 5.2.3.l' Introduction Several deep coreholes were drilled within the Hanford
-Reservation by Rockwell Hanford Operations during their geologic and geophysical investigations of the Pasco Basin.
Corehole DB-10, located in.the SW 1/4, sec. 29, T.13N., R.27E. (Figure 2K-32) intersected two zones.of reverse faulting (Myers and Price, 1979) at depths of 400 feet and 575 feet. The combined vertical offset was estimated at 160; feet.' Rockwell interpreted'the faulting to be part of an anticlinal ridge. No other deep coreholes were located in the immediate vicinity to assist in defining the attitude of'the faulting or of the basalt flows.
'As part of the geologic and geophysical study of the DB-10 area, Weston Geophysical conducted a detailed program of seismic refraction, gravity and land magnetics to supplement drilling and geological studies by Golder Associates.
The seismic refraction data were collected along. overlapping and reversed 800-foot spreads and gravity data were acquired at.100-foot station intervals. The land- , l magnetic data for many of the' lines in the DB-10 area were evaluated as not usable; three sets of power lines cross ) that area and limit the useful data to very short, inconclusive. segments. The-initial refraction studies defined a northwest-trending zone across which the near-surface velocities differed j significantly. Test pits were excavated by Golder Associates to investigate this anomalous zone. Test pit 6 disclosed an outcrop of basalt six feet below the' surface (Table 2K-1). The seismic coverage was subsequently expanded to the west to investigate this near-
-surface zone as well as apparently anomalous bedrock
. velocities. Upon completion of the borehole studies conducted by Golder Associates, several of the existing DB-10 lines were extended with seismic and gravity coverage, and-Line DB-10-8 was located to intersect the projected outcrop of the faulting defined by Golder Associates.
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S/HNP-PSAR 12/21/81 l 5.2.3.2 Discussion of Results 5.2.3.2.1 Seismic Data seismic refraction Profiles DB-10-1 through DB-10-8 (Figures 2K-34 through 2K-36 and Attachment C generally show higher, near-surface overburden velocities than are found elsewhere in the Hanford Reservation, the typical 1,000-2,000 ft/sec. shallowest material is less than 20 feet thick and is underlain by material with velocities ranging from 3,000 to 8,000 ft/sec. An analysis of materials excavated from tert pits (Table 2K-1) along the seismic refraction lines indicate a lateral variation in the composition of the gravels. These compositional changes define a northwest-trending transition zone which is indicated by the northwest-trending dotted line on Figure 2K-33. Lower velocities of 3,000-5,000 ft/sec. in the gravels found northeast of the transition zone correlate with a matrix of basaltic sand. The higher velocity material (6,000-8,000 ft/sec.) encountered southwest of the zone has a matrix of silt and clay with weak calcareous cementation. The seismic refraction data in the DB-10 area clearly define the northwest-trending basalt ridge indicated by the gravity data, as well as the drillhole data obtained by Golder Associates. Top of basalt elevations in the area of seismic lines DB-10-1 through DB-10-8 are between 460 feet and 260 feet. The seismic velocities for bedrock vary from 10,000 to 14,000 ft/sec. Seismic lines DB-10-3A, DB-10-5, DB-10-6 and DB-10-7 were located to explore the lateral extent of the 8,000 ft/sec. material that appear at the west end of Line DB-10-3. Shallow, competent basalt (12,000 - 14,000 ft/sec.) with a localized weathered zone (6,000-9,000 ft/sec.) in the vicinity of Test Pit 6 was found to extend across the entire DB-10 area. Profile DB-10-4 (Figure 2K-34) shows an anomalous low velocity zone in the basalt bedrock between Stations 12+00 and 16+00. A low velocity zone in the bedrock was encountered between Stations 6+00 and 10+00 on Profile DB - 10-8 (Figure 2K-35) and at Station 15+50 on Line DB-10-3 (Figure 2K-36). Seismic Profiles 7 and 8 (Figures 2K-37 and 2K-38) show an overburden sequence of 2,000-4,500 ft/sec. material underlain by 8,000-10,000 ft/sec. material. Isolated zones within the overburden have intermediate velocities that 2K-23 Amendment 23
S/HNP-PSAR 4/2/82 range from 5,000-8,000.ft/sec. The velocity of the basalt # varies from 13,000 to 14,500 ft/sec. in areas overlain by 100 f eet or more of the gravels. In areas where the basalt : is less than 100 feet below the surface the velocities ! range from 11,000 to 13,000 ft/sec. The seismic refraction [ data were used to contour the bedrock surface (Figure 2K- !
- 39) and bedrock velocity values (Figures 2K-40).
I 5.2.3.2.2 Gravity Data : i The Bouguer gravity map shown in Figure 2K-41 was processed with a density of 2.67 g/cm3 Because of the contrast in density between basalt and sediments (0.2 to 0.5 g/cm3), ; the map is controlled mainly by the topography of the : ~ basalt. The immediate DB-10 area is characterized by an f elongate, northwest-trending, gravity high located ! approximately one mile south of Gable Mountain and one mile ! west of the north-south trending May Jonction monocline. I t The residual gravity map for the DB-10 area is shown in ! Figure 2K-42. It is characterized by two major features: ! a northwest-trending elongate gravity high and the gravity . gradient indicating the location of the May Junction monocline. The elongate, gravity high, A, coincides with - the bedrock ridge which trends through the site of the DB- ' 10 drill hole. The crest of the bedrock ridge appears to be disrupted by a north-south to northeast-trending ;
" saddle". The dips on the flanks of the ridge are less than 200 24 5.2.3.3 Interpretations The bedrock high, A, was interpreted by Myers and Price h
l (1979) to be an anticlinal ridge. Their interpretation was , based upon a single drill hole, DB-10 and their aeromagnetic data. Subsequent drilling by Golder ' Associates across the southeastern nose of the bedrock ridge (Figure 2K-32) has confirmed the presence of 1 i anticlinal f olding (Figure 2K-43). This drill hole profile ; crosses the northwest-trending ridge where .it intersects ! the May Junction monocline. The structural section of - Figure 2K-43 theref ore contains interf erence f rom two different features, the'DB-10 anticline and the May Junction monocline. The change in the elev.itions between ! DH-97 and DH-93 contains two components. Furthermore, the line of drill holes is oriented at 450 to the trend of the bedrock high. l l 2K-24 Amendment 24
S/HNP-PSAR 12/21/81 The contour map of the top of basalt (Figure 2K-39), l developed from the seismic refraction data, shows a 1 northwest-trending bedrock ridge consistent with the gravity data. The southwest flank of the ridge is characterized by a steeper gradient than the northeast flank. The maximum slope of the bedrock surface on the southwest flank is 200 To the northwest the ridge becomes more symmetrical and the slope decreases to 100 The bedrock contours are disrupted 600 feet southeast and 800 feet west of corehole DB-10. Basalt elevations decrease from 460 feet to 400 feet along a north-south trend, and define saddles in the bedrock ridge. The bedrock seismic velocity in the DB-10 and adjacent areas (Figure 2K-40) decreases as bedrock elevations increase. Variations in basalt velocity (from 9,000 to 15,000 ft/sec.) are probably caused by a combination of weathering and fracturing due to folding. The velocity of near-surface and exposed basalt is generally lower than the velocity of more deeply buried basalt. The lower velocities at the ridge crest may be evidence of fracturing that could have been produced by the folding of the basalt. Another aspect of the bedrock velocity contour map that appears to be structurally controlled is the 2,400-foot-long, north-south trending, low velocity zone located 800 feet east of corehole DB-10 (Figure 2K-40). The low velocity zone occurs at the intersection of the bedrock surface and the upper DB-10 fault as determined by Golder Associates (Figure 2K-44). The residual gravity map defines a disruption in the crest of the ridge indicating a break in the bedrock slope or a low density zone at this locality. No offset of the bedrock surface was observed within this low velocity zone. The abrupt change in velocities and the residual gravity anomaly are attributed to a zone of breccia, the length of which is probably confined to the north-south zone described above. The bedrock velocities in the DB-10 and adjacent areas are indicative of anisotropic conditions in the basalt. They are consistently higher along north-south trending seismic profiles than on east-west profiles. The higher velocities (14,000-15,500 ft/sec.) approach the bedrock velocities measured in other areas (16,000 ft/sec.). The minimum values, however, are significantly lower (approximately 12,000 ft/sec.), and are likely caused by oriented fractures in the basalt. The overburden velocities in the vicinity of DB-10 range from 3,000 to 8,000 ft/sec. The velocity of the overburden material generally decreases away from the shallow bedrock ridge, especially to the southwest. The 6,000 to 8,000 2K-25 Amendment 23
S/HNP-PSAR 12/21/81 ft/sec._ overburden is present on either side of the basalt ridge. The flanks of the DB-10 anticlinal ridge dip at approximately 200 This value is consistent with the value obtained from drill holes 96 and 92. .Our interpretation of l the seismic data along Line 8 (Figure 2K-38) indicates that i the dip is due to anticlinal folding. This interpretation l
-differsisignificantly-from the interpretation by Seismograph Services Corporation of their Line 3-1, described in Myers and Price (1979) and shown in Figure 2K-
- 45. Gravity, drilling and refraction data. presented in this report do not support a fault in the vicinity of Station 476, of the magnitude and attitude shown in Figure 2K-45.
5.2.3.4 Summary The-gravity and seismic refraction data support the
. geologic interpretation that the upper DB-10 fault strikes
- north-south and dips 300 to the west.
1 The seismic refraction data limit the length of the upper
. DB-10 f ault to 2,400. feet, confining the fault to the small, northwest-trending, anticlinal fold south of Gable Mountain.
5.2.4 MAY JUNCTION AREA
-i 5.2.4.1 Introduction 1
t The eastern boundary of the first order antiform of the + Gable Butte-Gable Mountain segment is~the May Junction monocline, originally defined as the May Junction linear by Myers and Price (1979) on the basis of aeromagnetic data obtained by Rockwell Hanford Operations. Data acquired during the study of the May Junction monocline included gravity,. ground magnetic and seismic refraction. Seismic reflection data acquired by Rockwell were also used in the evaluation of the May Junction'monocline. Geophysical surveys in the DB-10 area (Section 5.2.3) extended-into the May Junction area and are discussed and/or cross-referenced where appropriate. t 2K-26 Amendment 23 I
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S/HNP-PSAR 10/14/82 5.2.4.2 Discussion of Results 5.2.4.2.1 Aeromagnetic Data The existing aeromagnetic data, those of Washington Public Power Supply System and Rockwell Hanford, exhibit similar f eatures to those identified f rom the gravity data collected f or Northwest Energy Services Company. The prominent north-south magnetic feature is the May Junction linear of Rockwell (Myers and Price,1979) . This north-south gradient (Figure 2K-46) intersects the northwest-trending magnetic anomalies to the west and bounds _a large, regional magnetic low to the east. The May Junction linear indicates the location of a known bedrock gradient with up to 350 f eet of relief based on drill hole and other geophysical data. 5.2.4.2.2 Gravity Data The Bouguer gravity map of the May Junction area shown in Figure 2K-47 was processed with a density of 2.67 g/cm3 Because of the contrast in density between basalt and sediments (0.3 to 0.7 g/cm3), the map is controlled mainly by the topography of the basalt. The gravity data acquired along eleven east-west traverse lines intersecting the trend of the May Junction monocline (Figure 2K-6A) provide greater detail on the configuration of the top-of-basalt. %% The gravity anomaly contours, as illustrated on the detailed Bouguer gravity map of the area (Figure 2K-47A), are consistent with a north-south trending bedrock surface sloping gently toward the east. The north-south trending May Junction gradient is produced by the change in depth to the top of basalt of approximately 350 f eet. A model of the subsurf ace geology that satisfies both the results of drilling and the gravity along Line 8C is shown on Figure 2K-47B. The densities used for the units are 2.60 g/cm3 f or the basalt, 2.45 g/cm3 f or the Ringold Basal Unit I gravel, and 2.0 g/cm3 for the Rattlesnake Ridge interbed and the remainder of the sedimentary section. The $,I elevation of the basalt surf ace varies smoothly. The maxi-mum slope of the basalt surf ace along the May Junction structure at Line.8C is 100 as determined by drilling data and gravity modeling. I 2K-27 Amendment 28
S/HNP-PSAR 10/14/82 1 5.2.4.2.3 Seismic Data The north-south trending May Junction linear observed in the gravity and magnetic data is clearly present on seismic l lines.7 and 8. Both lines show a steep rise of the bedrock surf ace f rom east to west with a maximum relief of 350 feet. As shown in the bedrock contour map (Figure 2K-48), the northwest-trending DB-10 ridge is not distinct at its projected intersection with Lines 7 and 8. The dominant north-south May Junction monocline interferes with the northwest trend of the DB-10 anticline. The bedrock surf ace on Line 8 is irregular at the intersection of the two trends. The bedrock velocities in the DB-10 and May Junction areas are indicative of anisotropic conditions. They are consistently higher along north-south trending seismic profiles than on east-west profiles. 5.2.4.3 Interpretation The May Junction monocline produces prominent anomalies in both the magnetic and gravity fields. The data indicate
- the presence of an eastward-dipping monocline about 2,000 f eet wide that strikes north-south f or a distance of approximately 2 miles. This interpretation is consistent with the drill hole profile shown in Figure 2K-43 (provided that the interference of structures in the DH-97, DH-93 area is recognized) and the drilling data noted on Figure i 2K47B. There is no evidence in the seismic refraction or the gravity data to support the f ault near Station 435 as proposed on the basis of the seismic reflection data by Seismograph Services Corporation (in Myers and Price, 1979 and shown on Figure 2K-45). The change of Bouguer gravity )I' anomaly across the May Junction monocline is due to the change of elevation of the top of basalt, change of density l
' in the Ringold section and variation of the regional Bouguer gravity anomaly; the change in elevation of top of ' basalt accounts f or at least 90% of the change. No evi-dence for offset is present. In the DB-10 and May Junction areas, the bedrock velocities are higher in a north-south direction than in an east-west direction. The higher velocities (14,000 to 15,000 ft/sec.) approximate the bedrock velocities measured in other areas (16,000 f t/sec. ) . The minimum values, however, are significantly lower (approximately 12,000 f t/sec.) and could be caused by (1) primary features in the basalt, (2) anisotropic (horizontal) stress, and (3) open fractures 2K-28 Amendment 28
, , y 4 wrPW9 -
S/HNP-PSAR 10/14/82 developed in the basalt and oriented north-south. Cause : No. 1 is rejected.because the same basalt unit is present i elsewhere on the reservattion and does not exhibit ! anisotropy outside the DB-10 area. Cause No. 2 is rejected as the chief cause of anisotropy because of the magnitude ! of the stress difference that is required. Nur and Simmons ! (1969) showed that a stress difference of 400 bars produced 154 anisotropy in dry Barre granite. A much larger stress ; dif f erence would be required f or saturated or partially i saturated rock. We attribute the cause of the anisotropy . to cause number 3, fractures in basalt. l ( The broad, first-order antiform of the Gable Butte-Gable i Mountain segment is bounded by the May Junction monocline. ! An elongate gravity high indicative of a small anticlinal ; fold extends across the southern portion of the May [ i Junction monocline. The geometry does not imply an age ; relationship between the two f eatures. This small northwest-trending anticline is separate and distinct from ! the Southeast Anticline. ! i 5.3 SOUTHEAST ANTICLINE 5.
3.1 INTRODUCTION
I l i t The aeromagnetic data acquired by Washington Public Power l Supply System (Figure 2K-49) show a magnetic high trending l southeasterly from the eastern end of Gable Mountain. Two i aeromagnetic survey blocks are joined along the axis of I this magnetic high. Those individual flight lines which- ! overlap f rom one survey block to another have been j evaluated and confirm that the magnetic high is real and ; not an artifact of merging the two aeromagnetic survey ! blocks. Rockwell's 1980 aeromagnetic survey of the Hanford ! Reservation area further confirms the existence of this , aeromagnetic high. Extensive seismic refraction, gravity [ and land magnetic data were acquired to characterize this ; anticlinal ridge and to define the structural relationships } between.the Southeast Anticline and the first , second , j and third-order folds of the Umtanum Ridge-Gable Mountain ! structural trend. ! F t
?
L i l
<<\ l
))> I 2K-29 Amendment 28 l,
- .. . -. r.-, . , - - - - - , - - . . . ,
S/HNP-PSAR 10/14/82 I5.3.2 DISCUSSION OF RESULTS 5.3.2.'1 Magnetic Data An aeromagnetic high, generally-symmetrical in shape, trends in-a southeasterly direction from the eastern end of Gable Mountain to the vicinity of Line 4C. At this location the anomaly decreases in amplitude and appears to be offset to the southwest.
~
This lower amplitude magnetic high continues trending southeasterly and then easterly in the~ vicinity of Lines 4E and 4F. The individual land magnetic profiles (Figure.2K-50)
-indicate a~ feature which may-be more complex than the aeromagnetic; data would indicate. A sharp anomaly'(A) trends.in a S60oE direction from Line 3 to Line 1-A but is not traceable south of Line 1-A.- The single peaked, . magnetic anomaly on Line 1 broadens and divides into two more subdued peaks 1(B and b) in the vicinity of Line 4B.
The northeasterly of the two southeast trends decreases in amplitude to a magnetic low (C) on Line 4D. The southwesterly of the two southeast-trending highs appears to continue southeast of Line 4D but is then offset in an en echelon manner, similar to the aeromagnetic data, to a southeasterly-trending lower amplitude magnetic high on Lines 4E and 4F (D). Land magnetic data acquired for the Supply System in the immediate vicinity of Borehole 125 on Line 4A (Weston Geophysical, 1982) have been contoured and are shown on Figure 2K-50A. A small residual magnetic high of gh approximately 25 gammas, located just southwest of Borehole 125, is consistent with a small undulation in the top of basalt.. 4 5.3.2.2 ' Gravity Data The gravity data processed at a density of 2.67-g/cm3 (Figure 2K-51) define a gravity high trending southeasterly
. from the Gable Mountain area.. Detailed gravity coverage (Figure 2K-6) shows that the northwest portion of this
, gravity feature;is quite linear and appears to extend one mile northwest of the eastern end of Gable Mountain. The southeast-trending gravity high is generally
- symmetrical in shape-and decreases in amplitude toward the southeast. Assuming that 1 milligal' gravity is equal.to about '150 f eet of basalt relief , the basalt surf ace _ slopes
/*
Sh6 2K-30 AmendmeM 28
~
~. - - - . . . - - . . . . . - . . - . . . - - . . - . . - . . . .
S/HNP-PSAR 10/14/82 l at angles ranging from 5 to 13 degrees. The gravity data clearly indicate that the southeast-trending feature changes trend to east-northeast in the vicinity of Lines 4C and 4D. 3 Gravity data acquired f or the Supply System (Weston [ l Geophysical, 1982) provide additional infctmation on two aspects of the Souteast anticline. First, a detailed ) survey in the immediate vicinity of Borehole 125 on Line 4A (Figure 2K-7A) has delineated a small localized rise in the surf ace of basalt consistent with the results of the detailed drilling program in that area (Golder Associates, 1982). This localized rise is indicated as anomaly A on DO the residual Bouguer anomaly map f or the area (Figure 2K-51A). Second, additional data acquired on Savage Island and east of the river (See Fig 2K-7B) constrain the extent of the Southeast anticline. The residual Bouguer gravity anomaly attributed to the Southeast anticline terminates in the vicinity of Savage Island (Figure 2K-51B). Therefore, the Southeast anticline does not extend east of the Columbia River. 4 5.3.2.3 Seismic Refraction Data Seismic refraction data across the Southeast Anticline have been acquired and profiled along Lines 3 (Figure 2K-52), 1 (Figure 2K-54), 4A (Figure 2K-55), and 4B (Figure 2K-56) and on the southwesterly side of the feature on Line 2 (Figure 2K-53). Seismic data were also obtained for portions of Lines 4C (Figure 2K-57), 6 (Figure 2K-58), and 6A (Figure 2K-59) to provide more inf ormation on the configuration of the bedrock surf ace in the area where the gravity and magnetic data indicated a change in the orientation of the feature. Seismic data were acquired on Line 6B (2K-60) to explore the northeast flank of the Southeast Anticline. Overburden seismic velocities in the area of the Southeast Anticline are, in general, typical of those encountered elsewhere in the Hanford Reservation. The low velocity (2,500-3,000 f t/sec.) overburden has a unif orm thickness of approximately 100 feet except at the northeast limit of the area near the Columbia River where it thins to 50 feet. Higher velocity overburden materials (9,500-10,000 f t/sec. ) underlie the lower velocity material southwest of the bedrock'high. The seismic velocity of this material changes to 6,500-7,500 f t/sec. northeast of the bedrock ridge. 2K-31 Amend 28
S/HNP-PSAR 10/14/82 The seismic velocity of competent basalt in the vicinity of the bedrock ridge is 15,000-16,000 f t/sec. Highly f ractured basalt above a depth of 250 f eet in Boring 125 (Line 4A, Figure 2K-55) correlates with a seismic velocity of 7,500 f t/sec. The higher velocity overburden materials also have a velocity of 7,200-7,500 ft/sec. over the anticline, precluding a determination of the lateral extent of the f ractured basalt along Line 4A. To the southeast of Boring 125, the velocity of 9,000-9,500 f t/sec. is indicative of cemented overburden materials as identified in Boring 122A. In Boring 109, northeast of Boring 125, the 7,200-7,500 f t/sec. material has been identified as overburden. The fractured basalt encountered on Line 4A in the vicinity of Boring 125 probably extends along strike of the ridge. Dif f erences between the seismic top of rock elevations and borehole bedrock elevations also occur on Lines 1, 3 and 4R along the southwest side of the bedrock ridge. Basalt elevations in Boreholes 105 (Line 1) and 37 (Line 3) are 50 to 100 f eet above the seismic top of high velocity bedrock (16,000 f t/sec. ) . The materials above the 16,000 ft/sec. horizon have a seismic velocity of 6,800-7,500 f t/sec. and are described in the boring logs as " weathered basalt." To the southeast, on Line 4B, " extremely weathered, fractured basalt" was logged in Boring 101 at elevation 234, 75 f eet above the top of seismic high velocity basalt. The profiles f or Lines 1 (Figure 2K-54), 3 (Figure 2K-52), and 4A (Figure 2K-57) show slopes on the high velocity bedrock ranging from 50 to 90 on each side of the bedrock high. The profile of the southwestern sioe of the bedrock ridge on Line 2 (Figure 2K-53) also exhibits a bedrock slope of approximately 100 All of the bedrock slopes described above are smooth. The top of high velocity basalt contour map (Figure 2K-61) compiled f rom the seismic ref raction data f or the Southeast Anticline defines a southeast-trending, broadly asymmetrical anticline f eature. The anticline extends from the vicinity of Line A to Line 4B where it changes trend from a southeasterly to an east-northeasterly direction. The southwest flank of the anticline has a slightly steeper gradient than the northeast flank. The f eature becomes symmetrical as it changes trend to the east-northeast; the maximum slopes on either flank of the ridge decrease to 80 hb 2K-32 Amendm
S/HNP-PSAR 10/14/82 5.3.3 INTERPRETATION Gravity, seismic refraction, land magnetic and aeromagnetic ~ data have defined a southeast trending anticlinal shaped f eature extending f rom the vicinity of Line A to Line 4C where it changes trend to east-northeasterly but does not ;Lt extend east of the Columbia River. Geochemical analysis of drill cuttings in this location identified the basalt surface as the same basalt unit. The anticlinal interpretation is based on the symmetry and broad shape of the aeromagnetic and land magnetic profiles across the f eature, as well as the slope of the basalt surface as defined by the gravity and seismic data. Slopes on the ' basalt surf ace as determined f rom the seismic and gravity data range from 5 to 16 degrees. > C% t i a i i r 2K-33 Amendm : 28
S/HNP-PSAR ~10/14/82 I l Ref erences f or PSAR Appendix 2K
- 1. Douglas, J. K. and Prahl, S. R., 1972, Extended Terrain Correction Tables f or Gravity Reductions:
Geophysics, V. 37, No. 2, p. 337-379.
- 2. Gardner, L. W., 1967, Refraction Seismograph Profile Interpretation: Seismic. Refraction Prospecting, A. W.
Musgrave, editor: Society of Exploration Geophysicists.
- 3. Golder Associates, Inc., 1981, Appendix 20: Gable Mountain Structural Investigations and Analyses, prepared for Northwest Energy Services Company, Kirkland, Washington.
- 4. Hammer, Sigmund, 1939, Terrain Corrections for Gravimeter Stations: Geophysics, V. 4, p. 184-194.
- 5. Mullineaux, D. R., Wilcox, R. E., Ebaugh, W. F.,
Fryxell, R., and Rubin, M., 1977, Age of the Last Major Scabland Flood of Eastern Washington, as Inferred from Associated Ash Beds of Mount St. Helens Set S: Geological Society of America Abstracts with Programs, V. 9, No. 7, p. 1105.
- 6. Myers, C. W. and Price, S. M., 1979, Geologic Studies of the Columbia Plateau: RHO-BWI-ST-4, Rockwell Hanford Operations, Richland, Washington.
- 7. Nilson, T. H., 1976, Washington Gravity Base Station Network: State of Washington Department of Natural Resources Division of Geology and Earth Resources, Information Circular 59.
- 8. Nur, A. and Simmons, G., 1969, The Effect of Saturation on Velocity in Low Porosity Rocks: Earth Planetary Science Letters, V. 7, p. 183-193.
- 9. Swanson, D. A., Wright, T. L. and Zietz, I., 1979, Aeromagnetic Map and Geologic Interpretation of the West-Central Columbia Plateau, Washington and Adjacent Oregon: U.S. Geological Survey Investigation GP-917, Scale 1:250,000.
- 10. Tallman, A. M., Lillie, J. T., and Caggiano, J. A.,
1978, Basalt Waste Isolation Program Annual Report: RHO-BWI-78-100, Rockwell Hanford Operations, Richland, Washington. c# 2K-34 Amendment 28
S/HNP-PSAR 10/14/82
- 11. (Ref erence deleted.) )
- 12. Talwani, M. and Landisman, M., 1959, Rapid Gravity Computations f or Two-Dimensional Bo6ies with Application to the Mendocino Submarine Fracture Zone:
Journal of Geophysical Research, v. 64, no. 1,
- p. 49-59.
- 13. Washington Public Power Supply System, 1974, WNP-l/4 Preliminary Safety Analysis Report, Chapter 2.5, Washington Public Power Supply System, Richland, Washington.
- 14. Washington Public Power Supply System, 1977, Preliminary Safety Analysis Report, Amendment 23, V.
2: Washington Public Power Supply System, Richland, Washington.
- 15. , 1981, WNP-2 Final Saf ety Analysis Report, Amendment 18, Appendices 2.5L and 2.5M:
Washington Public Power Supply System, Richland, Washington.
- 16. Webster, G. D. and Crosby, J. W. III, 1981, Stratigraphic Invest igation of the Skagit/Hanf ord Nuclear Project: prepared for Golder Associates, Inc., Kirkland, Washington.
- 17. Weston Geophysical Research, Inc., 1978a, Qualitative Aeromagnetic Evaluation of Structures in the Columbia Plateau and Adjacent Cascade Mountain Area: prepared for Washington Public Power Supply System, Richland, Washington.
- 18. , 1978b, Magnetic Properties of Basalts for the Columbia Plateau, Parts I and II: prepared f or Washington Public Power Supply System, Richland, Washington.
- 19. , 1978c, Ground Geophysical Studies, Columbia Plateau and Adjacent Cascade Mountains:
prepared for Washington Public Power Supply System, Richland, Washington. 2K-35
+
Amendment 28
i S/HNP-PSAR 10/14/82 I l
- 20. Zietz, I., Hearn, B. C., Higgins, M. W., Robinson, G. D., and Swanson, D. A., 1971, Interpretation of an Aeromagnetic Strip Across the Northwestern United States: Geological Society of America Bulletin, V. 82, No. 12, p. 3347-3372.
- 21. Golder Associates, 1982, The Southeast Anticline Fault: Evaluation of Attitude and Displacemt.nt:
prepared for Washington Public Power Supply System, Richland, Washington.
- 22. Weston Geophysical, 1982, Geophysical Studies of the Southeast Anticline and Vicinity, Hanf ord Site, Washington: prepared for Washington Public Power Supply System, Richland, Washington.
8
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2K-36 S' Amendment 28
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'S/HNP-PSAR 10/14/82 Appendix 2R Stratigraphic Investigation of the Skagit/Hanf ord Nuclear Project by Gary D. Webster and James W. Crosby III with Golder Associates Prepared for Golder Associates Bellevue, Washington Geological Engineering Section ,
i Washington State University l Pullman, Washington 99164 November, 1981 ] (Amended October, 1982) g 2R-i Amendment 28
y- _ - y;; s 12/21/81 S/HNP-PSAR p APPENDIX 2R CONTENTS ITEM TITLE PAGE 1.0 Summary 2R-1
'2.0 Introduction 2R-4 3.0 Development of . the Investigation 2R-5 4.0 Methodology 2R-6 41 Petrologic' Analyses: Sampling and 2R-6 Descriptive Techniques 4.2 Geophysical Techniques 2R-7 43 Interpretive Procedures 2R-9 4.4 Stratigraphic Correlations 2R-12 50 The Stratigraphic Section 2R-14 51 Columbia River Basalt Group 2R-14 52 Ringold Formation 2R-15 52.1 Age Range of the Ringold 2R-15 Formation 522 Lithologic Characteristics of the 2R-16 Ringold Cycles 5.2.2.1 Unit I 2R-16 5 2.2.2 Unit II 2R-17 5.2.2 3 Unit III 2R-18
.5 2 2 4 Unit IV 2R-19
-523 Borehole Geophysical ~ 2R-19 Characteristics of the Ringold Units 5.2.4 Environment of Deposition 2R-21 <
5.3 Pre-Missoula Flood Gravels 2R-22 2R-iii Amendment 23
n - JS/HNP-PSAR 12/21/81 ITEM TITLE PAGE 5.4 Missoula Flood Gravels 2R-22 5.5 Loess, Dune Sand , and Alluvial Sands 2R-23 60 Results 2R-24 6.1 Stratigraphic Development of the Post- 2R-24 Basalt Sediments 6.2 Structural Features and History 2R-28 6.2.1 Southeast Anticline Area 2R-28 6.2 2 May Junction Area 2R-30 6.23 Site Area 2R-31 70 References Cited 2R-33 APPENDICES Appendix 2R-A. Petrographic Descriptions , Appendix 2R-B. Geophysical Methods , Characteristics of Responses, and Supporting Data l I 1 2R-iv Amendment 23 l l i
+-- m; -
~
1 S/HNP-PSAR 12/21'/81 FIGURES NUMBER TITLE 2R ' Location Map of the Pasco Basin Showing Study Area
'2R-2 Major Structural Features in Study Area 2R-3 Lithologic and Geophysical Correlations of Coreholes 1 and 3~
2R-4 Drillhole Location Map Showing Areas Discussed in Text
-2R-5 Comparison of Gamma Ray Logs of Coreholes 1 and 3 Showing Correlating Units 2R-6 ' Comparison of Neutron-Epithermal Neutron Logs of Coreholes 1 and 3 Showing Correlating Units 2R-7 Structural Contour Map of the Top of Basalt 2R-8 Structural Contour Map of-the Top of Basal Unit I 2R-9 Structural Contour Map of the Top of Upper Unit I 2R-10 Structural Contour Map of the Top of Unit II 2R-11 Structural Contour Map of the Top of Unit III 2R-12 Structural Contour Map of the Top of Unit IV 2R-13 Isopach Map of Basal Unit I 2R-14 Isopach Map of Upper Unit I 2R-15 Isopach Map of Unit II 2R-16 Isopach Map of Unit III 2R-17 Isopach Map of Unit IV 2R-18 Isopach Map of Ringold Formation 2R-19 Stratigraphic Cross-Sections, Southeast Anticline Area, Lines 1 and 4A 2R- 20 Stratigraphic Cross-sections, Southeast Anticline Area, Lines 2 and 3 .
2R-21 Stratigraphic Cross-sections, Southeast Anticline Area, ' Lines 4 B, 4C, and 6A I 1 2R-v Amendment 23 1 1 y , - - - - - .-.
S/HNP-PSAR 10/14/82 l l
. NUMBER' TITLE 2R-22 Stratigraphic Cross-Sections, May Junction Area, Lines 1 and 2 2R-23 Stratigraphic Cross-Sections, May Junction Area, Lines 3, 8 and 8C gy 2R-24l Stratigraphic Cross-Sections, May Junction Area,
. Line 5 2R-25 Stratigraphic Cross-Sections, Site Area, Lines 1 and'4A 2R-26 ' Stratigraphic Cross-Sections, Site Area, Lines 4B and 4D 2R-27 Stratigraphic cross-Sections, Site Area, Lines M and M/W i 2R-28 Stratigraphic Cross-Sections, Site Area, Lines W and X-1 2R-29 . Suggested correlation of the Stratigraphic Section of the Skagit/Hanf ord Site with that of Myers and Price (1979) for the Pasco Basin
. 2R-30 Distribution of Unit II Green Waxy Clays P
2R-A-1 Interpretive Petrographic Log, Drillhole 1 2R-A-2 Interpretive Petrographic Log, Drillhole 3
- 2R-A-3 Interpretive' Petrographic Log, Drillhole 4 2R-A-4 Interpretive Petrographic Log, Drillhole 5 2R-A-5 > Interpretive Petrographic Log, Drillhole 6 2R-A-6 Interpretive Petrographic Log, Drillhole 7 i i
2R-A Interpretive Petrographic Log, Drillhole 8 2R-A-8 ' Interpretive Petrographic Log, Drillhole 9 2R-A Interpretive Petrographic Log,.Drillhole 10 2R-A-10 Interpretive Petrographic Log, Drillhole 11 2R-A-ll Interpretive Petrographic-Log, Drillhole 15 - a l 2R-A Interpretive Petrographic Log,.Drillhole 17. h 2R-vi Amendment 28
}_ .- S/HNP-PSAR 12/21/81 p l-L
. NUMBER TITLE 2R-A-13; Interpretive Petrographic Log, Drillhole 20
{ 2R-A-14 Interpretive Petrographic Log, Drillhole 21 h 2R-A-15 Interpretive Petrographic Log, Drillhole 22 2R-A-16 Interpretive Petrographic Log, Drillhole 23 2R-A-17 Interpretive Petrographic Log, Drillhole 24 2R-A-18 Interpretive Petrographic Log, Drillhole 25 2R-A-19 Interpretive Petrographic Log , Drillhole 26 2R-A-20 Interpretive Petrographic Log, Drillhole 27 2R-A-21 Interpretive Petrographic Log, Drillhole 29 2R-A-22 Interpretive Petrographic Log, Dri11 hole 30 2R-A-23 Interpretive Petrographic Log, Drillhole 31 2R-A-24 Interpretive Petrographic Log , Drillhole 32 2R-A-25 Interpretive Petrographic Log, Drillhole 33 2R-A-26 Interpretive Petrographic Log, Drillhole 34 2R-A-27 Interpretive Petrographic Log , Drillhole 35 2R-A-28 Interpretive Petrographic Log, Drillhole 36 2R-A-29 Interpretive Petrographic Log , Drillhole 37 2R-A-30 Interpretive Petrographic Log, Drillhole 30 2R-A-31 Interpretive Petrographic Log, Drillhole 39 2R-A-32 Interpretive Petrographic Log, Drillhole 40 2R-A-33 Interpretive Petrographic Log, Drillhole 41 2R-A-34 Interpretive Petrographic Log, Drillhole 42 2R-A-35 Interpretive Petrographic Log, Drillhole 43 2R-A-36 Interpretive Petrographic Log, Drillhole 44 2R-A-37 Interpretive Petrographic Log, Drillhole 45 2R-vii Amendment 23
S/HNP-PSAR- 12/21/81 NUMBER- TITLE 2R-A-30 Interpretive Petrographic Log , -Dri11 hole 4 6 2R-A-39 Interpretive Petrographic Log, Drillhole 47
.2R-A-40 Interpretive Petrographic Log, Dri11 hole 48 2R-A-41 Interpretive Petrographic Log , Drillhole 49 2R-A Interpretive Petrographic Log, Drillhole 50 2R-A-43 Interpretive Petrographic Log , Drillhole 51 2R-A-44 Interpretive Petrographic Log , Drillhole 52 2R-A Interpretive Petrographic Log , Drillhole 53 2R- A-4 6 Interpretive Petrographic Log , Drillhole 54 2R-A-47 Interpretive Petrographic Log, Drillhole 55 2R-A-48 Interpretive Petrographic Log , Drillhole 68 2R-A-49 Interpretive Petrographic Log , Drillhole 69 2R-A-50 Interpretive Petrographic Log, Drillhole 70 2R-A-51 Interpretive Petrographic Log, Drillhole 71 2R-A-52 :erpretive Petrographic Log, Drillhole 73 2R-A-53 Int rpretive Petrographic Log, Drillhole 74 2R-A-54 Interpretive Petrographic Log , Drillhole 78 2R-A-55 Interpretive Petrographic Log , Drillhole 92 2R-A-56 Interpretive Petrographic Log , Drillhole 93 2R-A-57 Interpretive Petrographic Log, Drillhole 94 2R-A-58 Interpretive Petrographic Log , Drillhole 96 2R-A-59 Interpretive Petrographic Log, Drillhole 97 2R-A-60 Interpretive Petrographic Log , Drillhole 98 2R-A-61 Interpretive Petrographic Log , Drillhole 99 2R-A-62 Interpretive Petrographic Log , Drillhole 100 ;
2R-viii- Amendment 23 1 5
ID S/HNP-PSAR 12/21/81 NUMBER TITLE 2R-A-63 Interpretive Petrographic Log, Drillhole 101 2R-A-64 Interpretive Petrographic Log, Drillhole 10 2 2R-A-65 Interpretive Petrographic Log , Drillhole 10 3 2R-A-66 Interpretive Petrographic Log, Dri11 hole 104 2R-A-67 Interpretive Petrographic Log, Drillhole 105 2R-A-68 Interpretive Petrographic Log, Drillhole 106 2R-A-69 Interpretive Petrographic Log , Drillhole 10 8 2R-A-70 Interpretive Petrographic Log , Drillhole 109 2R-A-71 Interpretive Petrographic Log , Dri11 hole 110 2R-A-72 Interpretive Petrographic Log, Drillhole 111 2R-A-73 Interpretive Petrographic Log, Drillhole 112 2R-A-74 Interpretive Petrographic Log , Drillhole 113 2R-A-75 Interpretive Petrographic Log , Dri11 hole 114 2R-A-76 Interpretive Petrographic Log, Drillhole 115 2R-A-77 Interpretive Petrographic Log, Drillhole 116 2R-A-78 Interpretive Petrographic Log , Drillhole 117 2R-A-79 Interpretive Petrographic Log, Drillhole 118 2R-A-80 Interpretive Petrographic Log, Drillhole 119 2R-A-01 Interpretive Petrographic Log, Drillhole 120 2R-A-82 Interpretive Petrographic Log , Drillhole 121 2R-A-83 Interpretive Petrographic Log, Drillhole 122 2R-A-84 Interpretive Petrographic Log , Drillhole 123 2R-A-85 Interpretive Petrographic Log , Drillhole 125 2R-A-86 Interpretive Petrographic Log, Drillhole E-1 2R-A-87 Interpretive Petrographic Log , Drillhole E-19 2R-ix Amendment 23
S/HNP-PSAR 10/14/82 . i NUMBER. TITLE l 2R-A-88 Interpretive Petrographic Log, Drillhole S-1 ; 2R-A-89 Interpretive Petrographic Log, Drillhole S-2 - 2R-A-90 Interpretive Petrographic Log, Drillhole S-3 ! 2R-A-91 Interpretive Petrographic Log, Drillhole S-4' i 2R-A-92 Interpretive Petrographic Log, Drillhole S-5 l 2R-A-93 Interpretive Petrographic Log, Drillhole S-6 2R-A-94 Interpretive Petrographic Log, Drillhole S-7 f 2R-A-95 Interpretive Petrographic Log, Drillhole S-8 i 2R-A-96 Interpretive Petrographic Log, Drillhole S-9 f f 2R-A-97 Interpretive Petrographic Log, Drillhole S-10 i 2R-A-98 Interpretive Petrographic Log, Drillhole S-ll , t 2R-A-99 Interpretive Petrographic Log, Drillhole S-12 ! 2R-A-100 Interpretive Petrographic Log, Drillhole S-13 l
-2R-A-101 Interpretive Petrographic Log, Drillhole S-14 f i
2R-A-102 Interpretive Petrographic Log, Drillhole S-15 2R-A-103 Interpretive Petrographic Log, Drillhole S-16 [ 2R-A-104 Interpretive Petrographic Log, Drillhole S-17 j 2R-A-105 Interpretive Petrographic Log, Dri11 hole S-18 2R-A-106 Interpretive Petrographic Log, Drillhole S-19 2R-A-107 Interpretive Petrographic Log, Drillhole S-20 2R-A-108 Interpretive Petrographic Log, Drillhole S-21 2R-A-109 Interpretive Petrographic Log, Drillhole S-22 2R-A-110 Interpretive Petrographic Log, Drillhole S-23 i 2R-A-111 -Interpretive Petrographic Log, Drillhole S-24 ! I k ; i 2R-x Amend 28 , _ . - . _ - _ - - _ - ~ , , - - - . . _ , _ . - _ _ . - _ _ _ _ - - - ~ . . ~ _ . , _ , _ . . . , _ , _
S/HNP-PSAR 10/14/82 l 1 l NUMBER TITLE
-2R-A-112 Interpretive Petrographic Log, Drillhole MJ-l 2R-A-113 Interpretive Petrographic Log, Drillhole MJ-2 h I
'2R-A-ll4 Interpretive Petrographic Log, Drillhole MJ-3 2R-B-1 Natural Gamma Cross-Section, Line 1 2R-B-2 Natural Gamma Cross-Section, Line 2 2R-B-3 Natural Gamma Cross-Section, Line 3 2R-B-4 Natural Gamma Cross-Section, Line 4A 2R-B-5 Natural Gamma Cross-Section, Line 4B 2R-B-6 Natural Gamma Cross-Section, Line 4C 2R-B-7 Natural Gamma Cross-Section, Line 4D 2R-B-8 Natural Gamma Cross-Section, Line 5 2R-B-9 Natural Gamma Cross-Section, Line 6A 2R-B-10 Natural Gamma Cross-Section, Lfae 8 2R-B-10A Natural Gamma Cross-Section, Line 8C b 2R-B-ll Natural Gamma Cross-Section, Line M 2R-B-12 Natural Gamma Cross-Section, Line M/W 2R-B-13 Nutural Gamma Cross-Section, Line W 2R-B-14 Natural Gamma Cross-Section, Line X-1 2R-B-15 Neutron-Epithermal Neutron Cross-Section, Line 1 2R-B-16 Neutron-Epithermal Neutron Cross-Section, Line 2 2R-B-17 Neutron-Epithermal Neutron Cross-Section, Line 3 .2R-B-18 Neutron-Epithermal Neutron Cross-Section, Line 4A 2R-B-19 Neutron-Epithermal Neutron Cross-Section, Line 4B 2R-B-20 Neutron-Epithermal Neutron Cross-Section, Line 4C 2R-xi Amend 28
S/HNP-PSAR 10/14/82 l l i NUMBER TITLE 2R-B-21 Neutron-Epithermal Neutron Cross-Section, Line 4D 2R-B-22 Neutron-Epithermal Neutron Cross-Section, Line 5 2R-B-23 Neutron-Epithermal Neutron Cross-Section, Line 6A 2R-B-24 Neutron-Epithermal Neutron Cross-Section, Line 8 2R-B-24A Neutron-Epithermal Neutron Cross-Section, Line 8C $I 2R-B-25 Neutron-Epithermal Neutron Cross-Section, Line M 2R-B-26 Neutron-Epithermal Neutron Cross-Section, Line M/W 2R-B-27 Neutron-Epithermal Neutron Cross-Section, Line W 2R-B-28 Neutron-Epithermal Neutron Cross-Section, Line X-1 2R-B-29 Neutron-Gamma Cross-Section, Line 1 2R-B-30 Neutron-Gamma Cross-Section, Line 2 2R-B-31 Neutron-Gamma Cross-Section, Line 3 2R-B-32 Neutron-Gamma Cross-Section, Line 4A 2R-B-33 Nebtron-Gamma Cross-Section, Line 4B 2R-B-34 Neutron-Gamma Cross-Section, Line 4C 2R-B-35 Neutron-Gamma Cross-Section, Line 4D 2R-B-36 Neutron-Gamma Cross-Section, Line 5 2R-B-37 Neutron-Gamma Cross-Section, Line 6A 2R-B-38 Neutron-Gamma Cross-Section, Line 8 $bI l 2R-B-38A Neutron-Gamma Cross-Section, Line 8C 2R-B-39 Neutron-Gamma Cross-Section, Line M 2R-B-40 Neutron-Gamma Cross-Section, Line M/W
)
f
- 2. , 11 .- A
S/HNP-PSAR 10/14/82 NUMBER TITLE 2R-B-41 Neutron-Gamma Cross-Section, Line W I 2R-B-42 Neutron-Gamma Cross-Section, Line X-1 2R-B-43 Gamma-Gamma Cross-Section, Line 1 2R-B-44 Gamma-Gamma Cross-Section, Line 2 2R-B-45 Gamma-Gamma Cross-Section, Line 3 2R-B-46 Gamma-Gamma Cross-Section, Line 4A 2R-B-47 Gamma-Gamma Cross-Section, Line 4B 2R-B-48 Gamma-Gamma Cross-Section, Line 4C 2R-B-49 Gamma-Gamma Cross-Section, Line 4D 2R-B-50 Gamma-Gamma Cross-Section, Line 5 2R-B-51 Gamma-Gamma Cross-Section, Line 6A 2R-B-52 Gamma-Gamma Cross-Section, Line 8 2R-B-52A Gamma-Gamma Cross-Section, Line 8C 7 2R-B-53 Gamma-Gamma Cross-Section, Line M 2R-B-54 Gamma-Gamma Cross-Section, Line M/W 2R-B-55 Gamma-Gamma Cross-Section, Line W 2R-B-56 Gamma-Gamma Cross-Section, Line X-1 QQ 2R-xiii AmendMS t 28 l l
S/HNP-PSAR ~12/21/81 TABLES I NUMBER TITLE 2R-1 XRF. Analyses for Dri11 hole Samples 2R-2 Lithologic Characteristics and Criteria Used to Define Stratigraphic Units 2R-3 Typical Geophysical Characteristics of Units 4 i t l 2R-xiv Amendment 23
S/HNP-PSAR 12/21/81 1.0
SUMMARY
'The Skagit/Hanford Nuclear Project Site is in the east- -central part of the Pasco Basin, a structural sub-basin of the larger Columbia Basin (Figure 2R-1). The Pasco Basin is ' partly surrounded by west- and northwest-trending anticlinal ridges, the Yakima folds, which are separated by broad synclinal troughs. The Saddle Mountains form the northern boundary of the Pasco Basin, and the Rattlesnake Hills and Horse Heaven Plateau form the southern boundary. The eastern boundary, formed by a gentle westward dip on the basalt surf ace,' extends slightly east of south f rom - the eastern end of the Saddle Mountains to a point approximately 20 miles east of Pasco, then turns southwest to Wallula Gap.
Umtanum Ridge and Yakima Ridge plunge eastward into the basin at the western boundary. The most prominent struc-tural features within and adjacent to the study area are the Gable Mountain anticline, the Southeast anticline, and the Cold Creek syncline (Figure 2R-2). Of these, only the Gable Mountain anticline is expressed surficially. The Pasco Basin is underlain by flows of the Columbia River Basalt ' Group, and these basalt flows are overlain by alluvium of the Ringold Formation and Pre-Missoula and Missoula Flood Gravels. This stratigraphic investigation encompasses approximately 47 square miles within the central part of the Pasco Basin. Because the youngest basalt flows ~are known to be deformed and faulted in some parts of the Pasco Basin, information regarding post-basalt deformation is impoctant to evaluate the age and amount of youngest deformation in the study area. The investigation has been carried out to determine both the general areal stratigraphy and details of strati-graphic relationships. In most of the study area, the basalt is overlain by three sedimentary formations: Pleistocene Pasco or Missoula Flood Gravels, Pre-Missoula Flood Gravels of late Pliocene (?) or Pleistocene age, and late Miocene-Pliocene Ringold Formation. These formations have a combined thickness of approximately 720 feet in the southwestern part of the study area. The Missoula Flood Gravels range in thickness from about 30 feet near May Junction to greater than 100 feet in the southeastern part of the study area. Pre-Missoula Flood Gravels are generally on the order of 100 feet thick. The Ringold Formation has a thickness generally greater than 200 feet except over the Southeast anticline. Surficial deposits consist of loess, dune sand, and alluvial sand of Recent or latest Pleistocene age. 1 1 2R-1 Amendment 23 1
S/HNP-PSAR 12/21/81 The Ringold Formation is comprised of lacustrine and alluvial sediments. The age of the Ringold section in the ,
. study area was considered by Gustafson (1978) and Myers and Price (1979) to be Pliocene (5.12 to 3.3 2 million years B.P.). New information f rom a palynological study by Leopold and Nickmann (1981), however, indicates that the basal units of the Ringold Formation are of late Miocene age. The age of the Pre-Missoula Flood Gravels is not known. The Missoula Flood Gravels are reported to be 13,000 to 19,000 years old (Mullineaux and others, 1977; Fulton and Smith, 1978 ; and Waitt, 1980). However, a recent study by Clague and others (1980) suggests that the major advance of the last Pleistocene glaciatio;3 into northeastern Washington and northern Idaho did not occur until af ter 17,500 years B.P. This implies that the Miss^ula Flood Gravels , which are the result of floods associated with that glaciation, were deposited between 17,500 and 13,000 years B.P. The Ringold Formation has been the primary target of this stratigraphic investigation because of its age, overlying relationship to the Columbia River Basalt, and continuity of sedimentary units. A combination of borehole geophysical logging and sedimentary petrologic techniques has been used to investigate the stratigraphy of this formation. The borehole geophysical techniques involved downhole logging with four radiation devices: natural gamma, gamma-gamma, neutron-gamma, and neutron-epithermal neutron tools. The data were digitized, computer processed, and plotted to enhance stratigraphic relationships. Composite analysis of the four geophysical logs indicated zones in which recog-nizable geophysical or marker horizons occur which could be used in stratigraphic correlation. Sedimentary petrologic studies consisted of examining core samples and rotary cuttings under a binocular microscope to identify the geologic characteristics of the samples. Lithologic deter-minations based on texture, color, roundness, cementation, and luster were recorded on lithologic logs for each drillhole.
The use of the geophysical marker horizons in conjunction with lithologic identification from the petrologic studies has allowed the correlation of four sedimentary units within the Ringold Formation in the study area, each representative of a depositional unit. Although the contacts between the units are unconformable, the available evidence indicates that only minor erosion of the upper surfaces of the units has occurred. These surfaces are believed, therefore, to have been generally horizontal over distances measured in miles at the time that the overlying unit was deposited. Structural contour maps, isopach maps, and stratigraphic sections have been constructed using the contacts of these sedimentary units. These maps and sections have been used to interpret the nature of structural deformation during and 1 i e , 2R-2 Amendment 23
S/HNP-PSAR 12/21/81 af ter deposition of the Ringold Formation in the study area. In general, all of the units within the Ringold Formation tend to thin or pinch out over the Southeast anticline and thicken toward the Cold Creek syncline to the southwest. Those Ringold units which continue across the Southeast anticline are warped, but younger units are less deformed than older units. The units within the Ringola section are interpreted to have been locally warped over basalt highs in the northwestern and southwestern parts of the study area. This. warping reflects deformation which started at least 14 million years B.P. (Myers and Price, 1979) and continued into late Ringold time (early Pliocene). This agrees with the general understanding of Yakima fold development in the Pasco Basin, which indicates that folding started approxi-mately 14 million years B.P. and became most intense between about 8 and 4 million years B.P. (Myers and Price, 1979). Deformation rates have decreased since that time according to Myers and Price (1979). No deformation is recognized in the Pre-Missoula Flood Gravels or Missoula Flood Gravels within the study area. 2R-3 Amendment 23
S/HNP-PSAR 12/21/81 1
2.0 INTRODUCTION
l r This report describes a stratigraphic and structural inves-tigation of .a portion of the Hanford Site conducted for the -Northwest Energy Services Company. The work was undertaken as a part of a broader investigation for a new reactor site at Hanford. The report integrates the results of support studies for Golder Associates, Inc., undertaken by Professor James W. Crosby III of the Geological Engineering Section, Washington State University, and Dr. Gary D. Webster, Consulting Geologist. The area of investigation is in south-central Washingtron within a large structural downwarp known as the Pasco Basin (see Figure 2R-1) . Within this basin, stratigraphic correlations have been made in the Ringold Formation to determine the age and extent.of post-basalt deformation.- Stratigraphic correlations have been based on a combination of geophysical techniques employed by Professor Crosby and sedimentary petrological studies employed by-Dr. Webster. 2R-4 Amendment 23
S/HNP-PSAR .12/21/81 3.0 DEVELOPMENT OF THE INVESTIGATION .The investigation was~ initiated by drilling two coreholes approximately.1300' feet apart. These two coreholes, 1 and 3, were drilled to determine whether the stratigraphic section could be correlated on the basis of lithology over short distances. Examination of the cores showed that correlation of-lithological characteristics was, in fact, possible.. In addition, examination revealed that the sediments. of the Ringold Formation accumulated during four major depositional cycles, herein referred to as units. .Each of these units began with the deposition of relatively coarse-grained sediments (usually gravels) in a high-energy environment and ended with finer-grained sediments (typi-cally silts) deposited in a low-energy environment. The two coreholes were geophysically logged using a suite of four radiation tools. Twelve recognizable geophysical markers were initially identified and correlated between the coreholes. These markers on the geophysical logs compared well with the stratigraphic section observed in the cores and demonstrated that the geophysical markers could be -directly related to lithologic characteristics. Geophysical markers-corresponding to six lithologic contacts ultimately were selected for use in making correlations throughout the study area and for constructing maps and sections. These six contacts are those found at the top of the basalt, top of Basal Unit I, top of Upper Unit I (A-horizon), and at the tops of Units II, III, and IV, respectively. Fig ure 2R-3 -shows five of these contacts that are present in coreholes 1 and 3.. Recognition of the correspondence between markers on the geophysical logs and lithologic contacts permitted lines of drillholes to be extended away f rom coreholes 1 and 3 without the need for continuous sampling. Therefore, rotary drilling techniques were used to advance additional drill-holes, using either mud or air to cool the bit and remove cuttings. Cuttings from the rotary dri11 holes were sampled, -and the drillholes were logged using the four radiation tools. Contacts determined lithologically and geophysically were-traced throughout the study area using the geophysical markers' observed in coreholes 1 and 3. Six additional core-holes were drilled during the later phases of the investiga-tion to confirm contacts extended into areas distant from coreholes 1 and 3. Figure 2R-4 shows the location of all drillholes in the study area, and delineates areas which are discussed in detail in following sections of this report. 2R-5 Amendment 23 l
S/HNP-PSAR 12/21/81 4.0 METHODOLOGY I 4.1 PETROLOGIC ANALYSES: SAMPLING AND DESCR4PTIVE TECHNIQUES Detailed.lighologic descriptions were made from sample chips from coreholes 1, 3, 73, 78, 94, 101, 102, 103, 125, E-1, and E-19 and for drill cuttings of'all rotary dri11 holes (Appendix 2R-A). Cores were sampled for laboratory analysis at 3-foot intervals and at lesser intervals where smaller lithologic changes occurred. Cuttings were sampled at 5-foot intervals from rotary drillholes. Cuttings were
- washed sufficiently to rcmove drilling mud or were used unwashed from drillholes drilled with air-cooled rotary tools. Lithologic descriptions were made on dry sampics using a stereoscopic binocular microscope with magnifica-tions to 100 power. Descriptions included lithologic type or types, color, grain size range and mode, roundness, character of mafics, degree of cementation, and where applicable, other characteristics such as luster, fissility, grain shape, or particular mineral abundance. Cuttings were compared to core chips to ensure the recognition of chart.c-teristic unit lithologies as contacts were traced laterally and to identify additional characteristics as they were observed in new drillholes.
Gravel sloughing is common in rotary drilling. As a result, some judgment is required to determine the lower contact of the gravels where they have sloughed into finer-grained samples below the contact. In some cases, sloughing has caused gravels to appear in sam below their actual occurrence. ples as much as 10 to 20 feet In coreholes, the gravel boundaries' correspond directly to geophysical character changes. Therefore, where sloughing of gravels was suspec-ted in rotary drillholes, the' geophysical logs were used to pick the contact of gravels with underlying materials. Lost circulation, change of rates of circulation of drilling fluids (mud or air), mechanical failure of equipment, the taking of incorrect samples from the shaker, improper sample
-washing, failure to take samples at specified times and intervals, and other human errors are possible explanations of why drill cuttings do not correspond exactly to drilling depths. Such differences which may vary from a few feet to several tens of feet generally increase with drilling depths and are referred to as indexing errors. The indexing error for cores is usually less than 5 feet and is commonly less than 1 foot. The indexing error for geophysical logs is usually less than 3 feet. Therefore, cuttings have been used to identify.lithologies encountered in sequence in 2R- 6 ' Amendment 23
S/HNP-PSAR 12/21/81 4
' dril1h' oles,' to provide tentative unit tops, and to verify
, identification of units determined geophysically.- Strati-graphic contacts, on the other hand, are recognized best in I cores, and, as has been stated previously, nearly direct correlations may be made between the cores and the geophysi-cal' logs. Because of this excellent correspondence, the geophysical logs have been used to establish contacts or other unique features within a stratigraphic unit and, in turn, have been used for correlation between drillholes and for construction of cross-sections and maps.
Contacts also have been determined approximately from cuttings and used for correlation purposes and map construc-tion; however, whenever geophysical logs were available, the geophysical markers were used for consistency and accuracy. 42 GEOPHYSICAL TECHNIQUES Test borings in the Ringold Formation require casing for support of the drillhole. Accordingly, the radiation group of geophysical tools was chosen for these studies, and the standard suite included natural gamma, gamma-gamma, neutron-epithermal neutron, and neutron-gamma tools. Of these, the neutron-epithermal neutron and natural gamma tools provided the more diagnostic logs. A brief descrip-tion of the radiation devices and their modes of operation is given in Appendix 2R-B-I. The geophysical logs initially revealed that there were at least twelve easily recognizable markers which could be correlated between the coreholes. Of these markers, those which were found to correspond to obvious contacts between the four lithologic units were selected as the basis for correlating and tracing interf aces within the Ringold Formation. The geophysical characteristics of each of the units'are described in Appendix 2R-B-II. The correspondence between geophysical responses and litho-logic units observed in cores is obvious throughout most of the study area, including locations several miles distant f rom coreholes 1 and 3. However, some interpretation is required in relating lithology and geophysical markers in rotary drillholes and in correlating units between these drillholes. ~ Unit boundaries are based in part on geophysi-
- cal characteristics of-the units (Appendix 2R-B-II) but also rely in large part on the recognition of a sequence of characteristic responses. Therefore, geophysical correla-tions:cannot.be made on sections removed from context, i.e.,
they~'are traceable only when they appear with their strati-
- graphic affinities.
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,~.
m.A.-
s [ E/HNP-PSAR 12/21/81 i In general, where a complete fining upward sequence (basal gravels and overlying sands and silts) is present, the units , , are sufficiently diagnostic on the geophysical logs that } their correlation between drillholes is apparent. However, above the geophysical A-horizon of Unit I, where parts of I the younger units are absent or poorly developed, unit } boundaries cannot be determined uniquely by the borehole geophysical technique. Figures 2R-5 and 2R-6 present comparisons between the gamma ray logs of coreholes 1 and 3 and the neutron-epithermal neutron logs of thise holes, respectively. The location of the top of the basalt and the top of each of the sedimentary units is shown. Although the Basal Unit I gravels are not present in coreholes 1 and 3, the top contact of these gravels is carried as a correlating horizon in holes in which they do appear. To be noted in the logs are the elevated gamma ray characteristics of the Ringold section, the reduction in gamma ray activity and porosity change at the basalt surface,.and the gross similarity of the sections. Other than the A-horizon (top of Upper Unit I), there are few consistent gamma ray features, although some can be traced to nearby holes. Despite the lack of areally extensive gamma ray markers, the general gamma ray characteristics of the units can be seen to be similar. In Figures 2R-5 and 2R-6, it is clear that gamma ray
" spikes" or high count rates are commonly associated with l materials that are obviously gravels on the neutron- '
epithermal neutron log. Although this observation is contrary to normal expectations, it was found to hold true uniformly for the Ringold deposits of the study area. It may be the result of higher gamma emissions from the clay rinds on the gravels (see Appendix 2R-B-I). Unit II is somewhat discordant with the sedimentary cycle format in that its lower contact is arbitrarily established at the geophysical A-horizon, which in turn, appears to be genetically related to a paleosol at the top of Unit I. Units III and IV each may be composed of more than one fining-upwards sequence, and therein lies the difficulty in uniquely establishing the contact between the units from geophysical data. The problem is further complicated by a lack of distinguishing lithological characteristics of the units. Geophysical tracing of contacts, therefore, required sufficiently close spacing of holes to permit recognition of newly introduced facies or the loss of facies in the section. On occasion, definition of sub-sequences was possible but was not included.
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S/HNP-PSAR 12/21/81 4.3 INTERPRETIVE PROCEDURES l The Elephant Mountain Member of the Saddle Mountains Basalt Formation is the youngest basalt present throughout the study area (see Section 5.1 for details). This flow is ! assumed to have been extruded over a geologically short period of time (Shaw and Swanson, 1970; Swanson and others, 1973). The top of the flow probably had a nearly horizontal f attitude in the Pasco Basin at the time that it crystal-I lized. A sequence of vesicular basalt grading downward into [ non-vesicular porphyritic basalt is recognized in both cores and cuttings throughout the study arec. Weathering of the top of the Elephant Mountain flow prior to the deposition of the overlying Ringold Formation is recognized in many cores and drill cuttings by the presence of a residual clay paleosol (B- and C-horizons) grading downward into unweath-ered vesicular basalt. The time duration for the formation of this clay paleosol is unknown but could have been a few hundred to several tens of thousands of years, depending upon climatic conditions. No ma]or erosional relief is recognized on this surface throughout the Site, because the vesicular flow top is found in most drillholes penetrating the basalt. Thus, the top of the Elephant Mountain flow is judged to be a reliable horizon for stratigraphic and structural interpretations. Unit boundaries determined on the basis of the petrologic and geophysical analyses have been used as markers of strat-igraphic contacts. These contacts are interpreted as having formed generally planar subhorizontal surf aces at the time of deposition and as being approximately time-correlative. The subhorizontal surface interpretation is supported by the general presence of fine-grained sediments in the upper part of each unit. These sediments would have been removed by erosion if much topographic relief had developed throughout the area prior to burial by the overlying unit. The time-correlative interpretation is supported by the presence of volcanic ash in a palcosol near the top of Unit I in drillholes 1 and E-19. Although not shown to be the same lithologic unit, an ash has also been identified in the Unit I paleosol in drill cuttings from each of the three sub- I
-areas of this study.
)
The geochemical nature of the A-horizon gamma ray spike is not t resently known ; however, it is consistently associated ! wit 3 the upper part of the paleosol of Unit I, and the two I are believed to be genetically related. The paleosol con-sists of a light to dark olive gray mixture of clay, silt, and sand. It contains weathered organic debris as seen in some cores and has been bioturbated. It is interpreted to be an aggrading soil A-horizon, developed in an alluvial 2R-9 Amendment 23 L .
S/HNP-PSAR 10/14/82 environment. Indepe'ndent identification of the top of the paleosol from the drill cuttings and the geophysical A-horizon gamma ray spike from the geophysical logs for 93 drillholes throughout the study area resulted in the markers being within plus or minus 10 f eet of each other in 88 percent of the drillholes and within plus or minus 5 f eet of each other in 60 percent of the drillholes. Statistically, therefore, and making allowence for indexing errors, the A-horizon and paleosol appese coincident within expected experimental error, and this lends considerable credence to the value of the A-horizon as a stratigraphic marker. For consistency in map construction, the gecphysical A-horizon was selected as the top of Unit.I. In five drillholes (47, 96, 97, and 99 and MJ-2), the top of Unit I was determined f rom cuttings at the top of the paleosol; the geophysical A-horizon was not recognized or geophysical logs were not available for these holes. Other contacts used in the interpretation are those between Units II and III, III and IV, and between Unit IV and the l Pre-Missoula Flood Gravels. Each unit is bounded on top and I bottom by unconformities. The unconf ormities are recognized by the sharpness of the contact in cores and on the geo-physical logs and by the abrupt change in lithology f rom l silts and sands below into gravels above. Unconformities ' between the Ringold units were found to coincide with the contacts between coarse and fine depositional sequences that are well displayed on borehole geophysical logs. Variations were noted in the type of fine-grained sediment below the same gravel unit as these contacts were traced laterally. Although the boundaries might be expected to mark an irregu-lar surf ace, they have been f ound to be laterally continuous and to lie on apparently subhorizontal and subplanar sur-f aces throughout most of the study area. The unconf ormities below Units I and II are developed upon paleosols. Paleo-sols are not found at the tops of Units II through IV. However, the upper, fine parts of each of these units are commonly present and suggest 1) that little erosion occurred on the tops of these units af ter deposition, and 2) that the time between deposition and burial of the units was insuffi-cient for paleosols to develop. These factors indicate that these contacts provide markers usef ul f or stratigraphic and structural interpretation where sufficient section is present to insure correlation of Ringold units. The post-Columbia River Basalt history of the study area is based on an interpretation of structural contour maps (Figures 2R-7 to 2R-12) , isopach maps (Figures 2R-13 to 2R-18),.one-to-one scale cross-sections (Figures 2R-19 to 2R-28), and computer-drawn geophysical cross-sections (Figures 2R-B-1 to 2R-B-56, Appendix 2R-B-III). These figures have been generated from the drillhole lithologic 2R-10 Amendme
S/HNP-PSAR 12/21/31 data (Appendix 2R-A) and geophysical log suites on the basis of contacts picked from the lithologic and geophysical logs. Structural contour maps were used to interpret the present structural configuration of the mapped unit. Isopach maps were used to determine thickness trends, distribution patterns, and paleoslopes. In addition, the isopach maps were used in con 3 unction with the structural contour maps and cross-sections to interpret paleostructure and paleo-topography. Examples of these interpretive uses of isopach maps, which are important in reconstructing the strati-graphic and structural history of an area, follow. An isopach map can be interpreted as a topographic reversal j map of the underlying undeformed surface when the top of the isopach interval is an undeformed planar time-correlative ) surface and the basal surface is an unconformity. On such a I map, the areas of greatest thickness reflect topographic f depressions, and areas of least thickness reflect topo-l graphic highs of the underlying surface. If the underlying l surface underwent deformation prior to or during deposition i of the isopach interval, then the isopach map will reflect a combination of topographic and structural relief. The isopach maps of Units II through IV are considered examples of this type of map. If the surface underlying an isopach interval is a deformed, uneroded, planar, time-correlative surface, then the isopach map reflects structural deformation prior to and during deposition of the isopach interval. An an example, assume that the basalt surface was deposited subhorizontally and that it was not extensively eroded prior to the deposition of Unit I. Then the isopach map (Figure 2R-13) of Basal Unit I (i.e., inverted topographic map of the basalt surface) may be used to interpret the structure developed between the time of deposition of the basalt and prior to the end of deposition of Unit I gravels. In this case, the structural relief on the basalt surface, which is here considered to equal the topographic relief, will approximate l' the total amount of thinning of the sedimentary unit (i.e., a minimum of 98 feet in the Site area and 124 feet in the May Junction area). The isopach map of Basal Unit I shows that the basal gravels are not present over the Southeast anticline nor the area along the May Junction linear in the May Junction area. l The isopach map (Figure 2R-14) of Upper Unit I (fines, l including the geophysical A-horizon and paleosol) may be l used for the area where tne basal gravels are not present. It shows a minimum of 80 feet of relief in the Southeast anticline area. Data from these two maps (Figures 2R-13 and 2R-14) may be combined and provide a total minimum relief of 2R-ll Amendment 23
x S/HNP-PSAR 12/21/81 212 feet for Unit I between the Southeast anticline (zero thickness) and the southwestern part of the May Junction area { 212 feet, drillhole 71). These combined maps give a i calculated minimum of 168 feet of relief in the Site area. 4.4 STRATIGRAPHIC CORRELATIONS Correlation or sedimentary units is based on the recognition of diagnostic lithologies and sequential order combined with the stratigraphic principles of superposition (older is deposited first, younger sediments above), original horizon-tality, and lateral continuity (sediments extend laterally until they pinch out, abut against a barrier, or interfinger into time-equivalent sediments). Several lithologies within the Ringold units, the Pre-Missoula Flood Gravels and Missoula Flood Gravels sequences, are easily recognized in both cores and cuttings. A preliminary stratigraphic sequence was established by observing the sediments in the cores of drillholes 1 and 3. Similar lithologies in the same sequential order are present in both cores, and bedding surfaces are horizontal, that is approximately normal to the long axis of the core. This stratigraphic seqLence was confirmed and traced laterally by observing and correlating the sediments found in cores from drillholes 73, 78, 94, E-1, and E-19 and from cuttings from intervening drillholes. l Coreholes 101, 102, 103, and 125 on the Southeast anticline show the lower part of this sequence ; however, the strati-graphic section if considerably thinner in these coreholes than in coreholes 1, 3, 73, 78, or E-19 In tracing the stratigraphic units through the study area, it was necessary to take into account lateral and vertical changes typical of an alluvial environment. Of the changes produced during deposition, most prevalent are those result-ing from changes in the flow regime and those resulting f rom the topographic configuration of the surface upon which the sediments were deposited. Changes in the flow regime between hi_h-energy flow and low-energy flow produced lateral facies changes and caused different lithologies to interfinger. This is especially apparent in Unit III where interfingering of sands and gravels is common. Relief on the various surfaces upon which the sediments were deposited also controlled the nature and distribution of lithologic types. Topographic highs were typically areas of non~ deposition or deposition of only fine-grained sediments. Coarse-grained sediments tended to accumulate in areas of lower topographic relief and were then overlain by finer-grained sediments. Coarse-grained sediments are most prevalent in the southwestern and central parts of the study 2R-12 Amendment 23
S/HNP-PSAR 12/21/81 area where they are well-developed in the basal parts of each of the units. The distribution of the various lithologies and the config- 'uration of structural contour and isopach maps do not support the existence of an integrated drainage network at any time during the deposition of the Ringold sediments. So, too,.only in localized areas do individual or groups of geophysical logs indicate the existence of channels which cut tens of feet into underlying sediments. Therefore, the effects of channeling are not considered to have signifi-cantly altered the unit boundaries at the scale employed for mapping structural contours. The effects of structural deformation on the stratigraphic section are seen in areas where the basalt surface and the overlying sediments have been up-warped. In these areas, units thin and often pinch out against the underlying warped surfaces. Recognition of this type of stratigraphic rela-tionship has been a major means of interpreting structural deformation in the study area. 2R-13 Amendment 23
S/HMP-PSAR 12/21/81 5.0 THE STRATIGRAPHIC SECTION I The stratigraphic section (Figure 2R-29) described in this report is based on initial description of cores from drillholes 1 and 3. This section was modified as other dri11 holes were investigated and lateral dif ferences recognized. Although direct correlations have not been established, the stratigraphic section of the study area is believed to be equivalent to parts of the previously defined section for the Pasco Basin (Myers and Price, 1979; Tallman and others, 1979) as shown on Figure 2R-29. The subdivision of the Pasco and Ringold Formations used herein of fers refinements of the stratigraphy for the Pasco Basin which Tallman (personal communication, October 1981) believes may be recognizable throughout a much larger area. These . refinements have been made possible by the close spacing of l drillholes in the study area. Earlier studies of the l Hanford Site have included part or all of the Pasco Gravels l in the Ringold Formation. 5.1 COLUMBIA RIVER BASALT GROUP Drillholes used in this investigation were typically drilled at least 20 to 50 feet into the basalt. Samples of the basalt from selected drillholes throughout the study area were submitted to Dr. P. R. Hooper (Washington State University) for X-ray fluorescense (XRF) analyses. Analyti-cal procedures used to determine oxide weight percentages are described by Hooper and others (1981), and the applica-tion of geochemical analysis to basalt identification by l other workers on the Columbia Plateau is described in Wright I and others (1973), Holden and Hooper (1976), Mc Dougall (1976), Wright and Hamilton (1978), Swanson and others (1979), Myers and Price (1979), and Wright and others (1980). X-ray fluorescence (XRF) analysis of samples from drillholes ( Table 2R-1) shows that the basalt underlying the Ringold Formation in the study area is the Elephant Mountain Member i of the Saddle Mountains Basalt Formation of the Columbia River Basalt Group. The Elephant Mountain Member has been dated as 10 5 million years B.P. (McKee and others, 1977). This flow has a vesicular flow top and is porphyritic and non-vesicular with depth. The upper parts of the flow are commonly weathered to an olive-gray clay paleosol up to 7 feet thick. The time required for formation of the clay is uncertain but suggests landscape stability in post-basalt to pre-Ringold time. Less-weatnered basalt is black to reddish-brown or brown. Underlying the Elephant Mountain l l { 2R-14 Amendment 23 , ' .l, ] ' . .l k ? ~ l .;,l ' ' { l j0kh : ' er i Y h .-) l
; : ( & &.M - A ~.S ~.' ' ' ' ' . : ~: > G > 1 ^:
S/HNP-PSAR 12/21/81 Member: is the Rattlesnake Ridge Interbed and the Pomona
-Member of the Saddle Mountains Basalt Formation. These
. units were penetratedHby several deep drillholes in the study area and.are readily identified on the geophysical logs.1 l
As a result of the generally weathered condition of the
- upper parts of the Elephant Mountain Member, the geophysical characteristics of the basalt are gradational upwards to the
~ base of the overlying Ringold Formation. In establishing the basalt contact with the Ringold on the geophysical logs, the selection has.been made at the change in gamma ray activity. This change may be minimal where the basalt is overlain by the highly basaltic. gravels of Basal Unit I.
Below the reduction in gamma activity, basalt porosity may
-decrease sharply at additional depths of 5 to 20 feet. The intervening -interval is interpreted to be clay or altered rock derived from weathering of the basalt. In some instances, the neutron logs demonstrate a higher porosity in the uppermost basalts than in the overlying Ringold strata.
This probably occurs whenever the basalt flow top is vesicular and intensely weathered. { l 52 RINGOLD FORMATION 521 AGE RANGE OF THE RINGOLD FORMATION l I
. Throughout _ the study area, the Ringold Formation is under-lain by the Elephant Mountain Member, which is dated at 10.5 million years B.P. (McKee and others, 1977). Brown and Brown (1961) suggested a late Miocene age for the basal part-of , the Ringold . Formation, which they incorrectly thought might be coeval with young interbeds in the basalts of.the Saddle 1 Mountains. Based on analyses of pollen and spores, Leopold and Nickmann (1981) also have suggested a late
' Miocene age for the lower part of the Ringold Formation.
Tallman (personal communication, October, 1981) suggests that the' Ringold in the Cold Creek syncline along the south-eastern part of the Pasco Basin is younger than the Ice l Harbor -Member of the Saddle Mountains - Basalt. The Ice I Harbor Member has been radiometrically dated at 8.5 million
' years B.P. (McKee and others,1977) . Gustafson (1978) and Myers and Price (1979) suggested a Pliocene age for the Ringold' Formation. Packer.and Johnston (1979) have sug-gested an age of 5.12 to 3.32 million years B.P. (the tine span of .the Gilbert Reversed . Magnetic Epoch) for sediments in part of the upper Ringold unit at White Bluffs. The Ringold section in the study area is considered to be bracketed by- the 10 5 and 3.32 million year dates (late Miocene to early Pliocene age).
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S/HNP-PSAR 12/21/81 5.2.2 LITHOLOGIC CHARACTERISTICS OF THE RINGOLD CYCLES l Examination of the lithology of coreholes 1 and 3 indicated that the Ringold Formation could be subdivided into four units, each consisting of a sedimentary cycle generally fining upwards. Subsequent detailed studies have shown that these units, with some modifications in thickness and lith-ology, are also recognizable in cuttings from drillholes up to 7 miles from coreholes 1 and 3. Each unit commences with alluvial gravels or sands at the base which are overlain by fine sands, silts, and clays, probably overbank sediments, l in the upper part. Subcycles are present locally within parts of each unit. The following summary of each unit, commencing with the basal part of Unit I, is based upon chips from coreholes 1, 3, 73, 78, 94, 101, 10 2, 10 3, 125, l E-1, and E-19, and from cuttings from rotary drillholes. l Logged core and cutting descriptions are given in Appendix 2R-A. Table 2R-2 summarizes the lithologic characteristics and criteria used to define the Units I through IV. 5.2.2.1 Unit I I The basal gravels of Unit I consist of light to medium bluish-gray to yellowish-gray, weakly to moderately well-cemented pebble to cobble gravel to conglomerate in a sand matrix. The gravels grade from sandy gravels (sand matrix filling in between touching gravel clasts) to gravelly sands (gravel clasts floating in a sand matrix), sometimes with thin sand stringers lacking gravel clasts. All grains and clasts are coated with a thin cement rind of clay with minor calcite (Simmons, personal communication, October, 1981). Sand grains are commonly cemented in the rind adjacent to gravel clasts. Cobbles are well-rounded, dominantly basal-tic at the base, with well-developed weathering rinds or, in pebbles and some smaller cobbles, weathered throughout. Secondary pebbles and cobbles include quartzite, granitics, volcanics, and volcaniclastics. The matrix is fine- to coarse-grained, angular to subangular sand. Basalt grains are common, and, when coated with the cement rinds, have a distinct bluish color. Mafics may be up to 25 percent in these sands. Quartz, feldspar, and mica are the other most common minerals in these sediments. Cementation is suffi-cient to bind many sand grains together to form sand clasts found when disaggregation of the sediment is attempted. The gravels are well-developed in coreholes 73, 78, and E-19. Unit I basal gravels occur along the southern edge of the Southeast anticline area, eastern part of the May Junction area, and throughout the Site area (Figure 2R-13). They are 2R-16 Amendment 23
S/HNP-PSAR 12/21/81 absent on Line 8 and over the Southeast anticline. The , basal contact is a nonconformity, and the gravels grade ; upward into the overlying fine sediments of Unit I. These gravels are considered equivalent to the basal Ringold unit as defined by Tallman and others (1979). ) l Upper parts of Unit I commonly consist of olive-gray to light olive-gray to gray, flakey silty clay, or clayey silt. Less common is sand, composed of angular to subrounded grains, medium- to coarse-grain size, with up to 30 percent mafics, rare fragments of carbonized wood, and moderate to no cement. Fine- to medium-grained, angular to subangular sand grains are commonly present floating in the clayey silt. Rarely, thin very fine- to medium-grained light gray sand beds or stringers occur interbedded with the silty clays and clayey silts. A thin ash horizon occurs in the upper part of Unit I fines ir. coreholes 1 and E-19 An ash was also noted in many of the rotary drillhole cuttings. Fine sediments in the uppermost part of Unit I, typically olive-gray micaceous sandy silty clay, form a paleosol of variable thickness marking the end of Unit I. An erosional unconformity forms the upper surface of the unit. The fines of Unit I are referred to as " blue clays" by drillers in the Pasco Basin and are believed to be equivalent to the lower part of the lower Ringold unit as defined by Tallman and others (1979). Pollen analyses by Leopold and Nickmann (1981) suggest a late Miocene age for the fines of Unit I. 5.2.2.2 Unit II ; Gravels at the base of Unit II are generally thin, if present, and are typically pale yellowish-gray to yellowish-brown ferruginous sandy gravels to gravelly sands. Clasts - are well-rounded pebbles to small cobbles of basalt, quartz- l ite, volcaniclastics, and granitics. Weathering rinds on i basalt clasts are well-developed. Gravel clasts generally float in fine- to coarse-grained, angular to subrounded sand ] a grains of quartz, basalt clasts, feldspar, mica, and mafics 1 (up to 10 percent). Commonly, the sand grains are coated with a very thin cement rind, but grains are easily disaggregated and friable. Gravel clasts generally have a yellowish-brown cementation rind (clay with some calcite; Simmons, personal communication, 1981) with adhering sand Jl grains. Interbedded with the gravelly sands are laminated ] sands, silty sands, and silty clay beds which are light 1 yellowish-gray with ferruginous staining in part. The basal -l gravel may be underlain by a yellowish-gray silty sand to clayey silt which is considered a subunit of Unit II. This , subunit is thin and not present in all drillholes. 2R-17 Amendment 23
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-The upper part of Unit II is characterized by fine-grained sediments commonly containing greenish-gray to yellowish- g gray silty clay and clay interbedded with yellowish-gray to light olive-gray sands and sandy silts. The silty clays and clays are platy to blocky, grayish-green to varicolored, have a'high waxy luster, and occasionally are bentonitic.
The waxy clays ( Figure 2R-30 ) are distinctive but not as continuous as the fines of Unit I. The sands and sandy silts.are often ferruginous and contain up to 25 percent mafics. Sand grains are sometimes ccated with a thin cement rind and are very friable. Silts and fine sands of Unit II lacking the waxy clays are not distinguishable from silts and fine sands of Units III and IV, unless they are found in stratigraphic sequences underlain by Unit I. This is a common occurrence along the crest of the southeastern part of the Southeast anticline. Unit II sediments are founded by erosional unconformities. The exact age of Unit II sediments is uncertain, but pollen analyses by Leopold and Nickmann (1981) suggest a late Miocene age. They are believed to be equivalent to the middle and upper parts of the lower Ringold unit as defined by Tallman and others (1979). 5.2.2.3 Unit III Gravelly sands to sandy gravels in the lower part of Unit III are yellowish-gray, and the well-rounded pebbles and cobbles commonly have yellowish cement rinds with sand grains adhering to the clasts. Clay cement rinds (Simmons, personal communication, October, 1981) are occasionally calcareous. Clasts tend to float in the sand matrix, but the matrix sand may be absent. Clasts consist of basalt, quartzite, gneiss, granitics, and volcaniclastics. Thick weathering rinds occasionally occur on basalt clasts. The sand matrix is fine- to coarse-grained, may be silty to rarely clayey in part, mostly angular to subangular, with some subrounded to well-rounded grains in the coarse-grained fraction. Grains are mostly quartz but may also be feldspar, mica, and up to 30 percent mafics. Gravels in Unit III are similar megascopically to those of Unit IV. However, they are thick and make good diagnostic correlation zones when used together with other.lithologies present in the stratigraphic sequence. Fine sediments in the upper part of Unit III are interbedded sand and silty sands with clayey silt or silty clay at the top of the sequence. Sediments are commonly yellowish-gray, and sands are generally well-sorted, subangular to sub-rounded, fine- to medium-grained, rarely coarse-grained, and lack cement. Although dominantly quartz, sands typically 2R-18 Amendment 23
S/HNP-PSAR 12/21/81 contain mica and up to 20 percent mafics. Erosional unconformities occur at the base and top of Unit III. Based on lithologic similarity, Unit III gravels and fines are believed to correlate with the lower gravels of the middle Ringold unit as defined by Tallman and others (1979). Middle Ringold gravels are exposed at the base of the bluffs along the eastern side of the Columbia River south of Ringold Flat, approximately 8 to 12 miles east of the study area. 5.2.2.4 Unit IV Gravelly sands to sandy gravels in the basal part of Unit IV are lithologically like those in the base of Unit III and also grade upward into finer clastic sediments. Fine sediments in the upper part of Unit IV are interbedded yellowish-gray to dusky-yellow silts, sands, silty sands, and sandy silts. Grains are angular to subangular, moder-ately to well-sorted, contain up to 25 percent mafics, and commonly are uncemented. They are megascopically very similar to the fine-grained sediments in the upper part of Unit III. Based on lithologic similarity, the gravels of Unit IV are believed to correlate with the upper gravels of the middle Ringold unit as defined by Tallman and others (1979). Fine sediments of Unit IV are considered to correlate with the basal part of the upper Ringold unit of Tallman and others (1979). Both middle and upper Ringold sediments are exposed along the bluffs on the eastern side of the Columbia between Taylor and Ringold Flats in the eastern part of the Pasco Basin. 5.2.3 BOREHOLE GEOPHYSICAL CHARACTERISTICS OF THE RINGOLD UNITS 1 Throughout most of the central and southern part of the study area, the Ringold sequence displays a uniform but somewhat atypical group of geophysical characteristics. They are atypical in that the natural gamma activity of many of the coarse clastic zones is greater than that of the associated fine clastics. This is contrary to the normal expectation for an alluvial environment, whereas the poros-ity and density responses, as indicated on the neutron logs, are generally typical of such settings. Individual fine and coarse clastic sequences commonly can be traced on the geo-physical logs for considerable distances (to the limits of 2R-19 Amendment 23
S/HNP-PSAR 10/14/82 the study area in the case of some fine-grained units) . More detailed information on the geophysical characteristics of each stratigraphic unit and the resolution of the bore-hole geophysical responses is presented in Appendix 2R-B-II. Table 2R-3 summarizes the geophysical characteristics of each unit. Source-detector spacing of the neutron-epithermal neutron tool used in these investigations moved the neutron response beyond the " cross-over" zone, so that increases in hydrogen, or water content, lowered the number of detectable epither-mal neutrons. Accordingly, a high water content in the sediments causes a reduction in neutron flux or an excursion to the left on the logs. As fine-grained sediments charac-teristically have higher percentages of interstitial voids than do coarse sediments, they have higher porosities, contain more water, and display reduced neutron activity. Therefore, the sedimentary units can be seen on the neutron logs to represent generally fining-upwards cycles of deposi-tion and to display typical neutron responses. Comparison of logs f rom certain adjacent drillholes suggests the presence of minor local cut-and-fill structures within cycles. It is evident, too, that facies changes are common in some of the units, as would be anticipated in an alluvial depositional environment. Where facies change rapidly, some subtle geophysical markers probably cannot be f ollowed with confidence in drillholes more than a few hundred feet apart. In the southern part of the Southeast anticline area, in the eastern part of the May Junction area, and in the Site area (Figure 2R-13), drillholes commonly intercept the basal con-glomeratic and gravel unit below the fine-grained sequence of sedimentary Unit I. This conglomeratic-gravel unit has been treated as though it were the basal unit of Unit I. However, the physical and chemical characteristics of these deposits as indicated by the geophysical logs are grossly dif f erent f rom the overlying Ringold section. The basal conglomerate of Unit I has a higher density and lower poros-ity than younger gravels in cores of drillholes 73 and 78 and could cause gravimetric determinations of depth to basalt to be in error. Over the Southeast anticline and the May Junction monocline, I the Unit I section thins, largely through the elimination of {$ the gravel facies but also by thinning of the fine-grained clastic f acies. In these areas, the characteristic l 4gr geophysical signatures of the units on the logs are more subtle than in the remainder of the study area.
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i S/HNP-PSAR 12/21/81 j i l . 5 2.4 ' ENVIRONMENT OF DEPOSITION j i ( The environment of-deposition of the.Ringold Formation has ! been; interpreted as primarily fluvial with some contribution ! from . floodplain and lacustrine environments (Tallman and . others, 1979; Leopold and Nickmann, 1981). Sediments i <- observed in the cores and cuttings from the study area are ; consistent with-this interpretation. In addition, some of i i the well-sorted silts and very fine. sands in the upper parts j of Units II through IV probably represent loess deposits and ! sand dunes. t
. . i
. Coarse sediments at the base of each of the units are gener-ally matrix-supported gravels or gravelly sands; only rarely ;
.are matrix-free gravels found in the cores. The matrix-free j intervals in the cores represent higher energy depositional !
' levels in which the finer sediments were retained in suspen- !
sion as the pebbles and cobbles were deposited. As current j ~
. velocity decreased, matrix-supported gravels were deposited -
and typically grade vertically and laterally into gravel- I f ree n sand s . Thin sand lenses and interfingering of sand { beds: (especially in Unit III) in the gravels suggest a i
- pebbly braided alluvial environment (Collinson, 1978) such !
as a large-scale alluvial fan or very_ wide braided stream , channel. The abundance of non-basalt clasts in the gravels t clearly indicates a source from outside the Pasco Basin. l l The clean, fine- to medium-grained sands in the middle and h , upper parts of each of the units are interpreted as channel deposits formed in intermediate flow regimes. The very fine-grained, well-sorted clean sands are considered to l' represent lower-energy channel sands ard floodplain dune , sands. Fine-grained materials, ranging in size from clays ! to fine sands, are commonly very thinly bedded or laminated i in-the cores and are interpreted to be overbank and lacus- ! trine floodplain deposits. The presence of plant fragments I and pollen in samples of these finer-grained sediments from ' coreholes 1, 3, and 78 and the development of paleosols i support this interpretation. The presence of other non- ! basalt-derived minerals in'the finer sediments indicates a i 1 through-flowing fluvial medium bringing sediments into the l Pasco Basin from highlands of non-L saltic composition. l i ; The absence of most of the upper Ringold Formation in the (
- s study area is accounted for by post-Ringold Formation erosion or possibly non-deposition.- Cyclic deposition in the Ringold. Formation is obvious when the stratigraphic .
sequence is observed. However, the f actors controlling the i cyclical nature are unknowr.. They could include fluctua- i tions in erosional conditions in the source areas and the i influence of tectonic activity in the Pasco Basin. ! I r l
< t 2R-21 Amendment 23 j
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- k s - 3 .? ?~. ~ ' F ^:, *: y u C I- l r . . W.< A A'C s_-).'b,W C K ,? Q % 64-%
S/HNP-PSAh 12/21/81 5.3 PRE-MISSOULA FLOOD GRAVELS I Gravels unconformably overlying the Ringold Formation in the study area ace dominantly clasts of granite, quartzite, gneiss, and rhyolite porphyry, with subordinate basalt clasts. Non-basalt clasts may have been derived in part from the Ringold Formation. Clasts are well-rounded and generally embedded in a sand matrix. Weathering rinds on the basalt clasts are thin and poorly developed. Thin, light gray to white, well-sorted , medium- to coarse-grained , angular to subangular sands with up to 10 percent mafics are occasionally present within these gravels. Gravels of the Pre-Missoula Flood Gravels are distinguished f rom Ringold gravels by a lack of yellow cement rinds and in some cores by a lack of matrix sand. In cores they have a white j appearance. They are distinguished from Missoula Flood Gravels by the presence of up to 60 percent non-basalt clasts of quartzite, granitics, volcanics, and volcani-clastics. A high velocity seismic refracting layer (8,000 to 10,000 ft/sec) is present in the lower part of the Pre-Missoula Flood Gravels (Weston Geophysical Corp., 1981a). This layer is generally flat-lying throughout the study area and may be associated with materials having a clay matrix. The Pre-Missoula Flood Gravels form a subsurface sheet-like deposit across the Hanford Reservation. Although the prov-enance and age of these gravels have not been determined, their fabric, composition, and lateral extent suggest that they probably represent pre-sisooula, large-scale flood deposits, possibly from late Pliocene (?) or early Pleistocene glaciations or early Missoula-type flood epi-sodes which were restricted to the Spoxane River and Columbia River drainages. These gravels are equivalent to the basal part of the Pasco Gravels of the Hanford Formation as defined by Tallman and others (1979). They are recog-nized as a separate stratigraphic unit in the study area because they are lithologically distinct from underlying and overlying units. 5.4 MISSOULA FLOOD GRAVELS Missoula Flood Gravels are present across the Hanford Reservation either exposed on the surface or capped by loess, dune sands, or alluvium. These gravels unconformably overlie the Pre-Missoula Flood Gravels and formed as the result of large-scale floods released from Lake Missoula in Montana. Missoula flood deposits have been assigned an age range of 17,500 to 13,000 years B.P. based on the presence of St. Helens "S" ash near the top of the unit (Mullineaux 2R-22 Amendment 23 _ __ mm i .. _ _ _ _ _ _
S/HNP-PSAR 12/21/81 and others, 1977) and the ages of glaciation in southern i Canada.and the northwestern United States (Fulton and Smith, 1978; Clague and others, 1980,). The Missoula Flood Gravels are pebble to cobble gravels which may or may not contain interbedded coarse sands. The gravels are characterized by a dominance of basalt, commonly 95 percent, with a few clasts of granitics and metamorphics. The sands are dark gray from the high basalt content but also contain quartz, feldspar, and mica; they are uncemen-ted. These gravels represent rapid deposition from sediment-laden water, which is generally reflected in their lack of matrix sand. They are equivalent to the upper part of the Pasco Gravels as defined by Tallman and others (1979). ; l l 5.5 LOESS, DUNE SAND, AND ALLUVIAL SANDS Surficial sediments unconformably overlying the Missoula Flood Gravels are thin and were generally not sampled. These sediments are described in Myers and Price (1979, Table III-2, p. III-10). The loess, dune sand, and alluvial sand are intricately related and are all of Recent age or latest Pleistocene age. l l l 2R-23 Amendment 23
t-S/HNP-PSAR 12/21/81 6.0 RESULTS I 6.1 STRATIGRAPHIC DEVELOPMENT OF THE POST-BASALT SEDIMENTS Observations of the post-basalt sediments based on the lithologic and geophysical study of the sedimentary section show several depositional patterns or trends and marker horiz: ns that are significant throughout much of the study area. These observations and their interpretations are as follows:
- 1. The Elephant Mountain flow forms the uppermost basalt throughout the study area, and the vesicular flow top is recognized in cores and cuttings. This suggests that:
- a. No significant erosion incised the area prior to deposition of the overlying Ringold Formation, and
- b. The Elephant Mountain Member is a good refer-ence surface for mapping purposes.
- 2. An extensive residual clay paleosol up to 7 feet thick-(corehole 78) and a weathered basalt interval up to 9 feet thick (corehole 125) are present on top of the Elephant Mountain flow throughout much of the study area. Development of a residual clay paleosol suggests landscape stability and low topographic relief for the area during the time of development of the paleosol. The time duration of development is unknown. If climatic conditions were like the arid climate of the Pasco Basin today, the paleosol would imply long periods of time, perhaps in the hundreds of thousands of years. Conversely, if warm, humid climatic condi-tions-prevailed, then the paleosol could have developed in a few hundreds or a few thousands of years.
3 Ringold, Pre-Missoula, and fine-grained Missoula sediments contain a high percentage of non-basaltic particles, whereas Missoula coarse-grained sedi- i ments contain a low percentage of non-basaltic j particles. This is interpreted to indicate that: 1
- a. The non-basaltic materials in the Ringold, Pre-Missoula, and Missoula sediments were derived from areas adjacent to the Columbia Plateau, 2R-24 Amendment 23
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- b. More sediment was transported into the Pasco Basin during Ringold, Pre-Missoula, and Missoula times than could be removed, or general subsidence of the Pasco Basin occurred during this time interval,
- c. Coarse-grained sediments of the Missoula Flood Gravels were derived from different areas and were deposited by different processes than the coarse-grained Ringold sediments, and
- d. Coarse-grained sediments of the Pre-Missoula Flood Gravels were derived from the same areas but were deposited by a different process than those of the Ringold sediments.
- 4. Gravels of Basal Unit I contain many non-basaltic clasts, thin to the northeast and northwest, and are confined to the central and southern parts of the study area. This suggests that:
- a. The Southeast anticline and May Junction mono- 2.lf cline were low-lying positive area while the gravels of Basal Unit I were being deposited, and
- b. Offlap, pinchout, or infilling of structural l lows in the study area to the south and west of l the Southeast anticline and south and east of $3r the May Junction monocline occurred during Basal Unit I time.
- 5. Gravels of Basal Unit I thicken in the southern part of the May Junction area and thin to the east.
Fine-grained sediments of Unit I are thin in the southwestern part of the May Junction area and thicken to the east. Basal gravels of Unit I are thinner (approximately 25 f eet) in drillhole S-3 than in all surrounding drillholes. Fines of Unit I are considerably thicker (approximately 45 feet) in drillhole S-3 than in all surrounding drill-holes. This is interpreted in the f ollowing manner: l
- a. A change of facies is believed to occur in Unit I with the basal gravels interfingering into fine sediments in the southwestern to eastern part of the May Junction area and in the vicinity of drillhole S-3 in the site area, and
- b. The fine-grained sediments in the upper part of Unit I are a part of the same depositional v' cycle as the basal gravels but represent a -
4 decrease in the energy level. 4 l 2R-25 Amendment 28
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- 6. Sediments in Upper Unit I are composed of olive-gray to brownish-gray silts and clays with some very fine to fine sand. They are uncemented, contain organic fragments, are bioturbated in some
, areas, and may show thin laminations. They are present throughout the study area except along the northwestern part of the crest of the Southeast anticline and the crest of the subsurface ridge of basalt on the western side of the May Junction mono-cline in the May Junction area. These sediments are interpreted as:
- a. An aggrading paleosol, probably developing on a flood plain, and
- b. An indication of landscape stability for the late part of Unit I time.
- 7. Upper Unit I sediments are present throughout the study area except along the northwestern part of the crest of the Southeast anticline (drillholes 105, 34, 38, and 37) and the crest of the subsur-face basalt ridge on the western side of the May l $N Junction monocline (drillholes 92 and MJ-3) . They l thin around these structures and thicken to the southeast. This is interpreted in the f ollowing manner:
- a. Paleoslopes existed to the southeast during Upper Unit I time, and
- b. The Southeast anticline and subsurface basalt ridge west of the May Junction linear were low-lying po91tive areas during deposition of the Upper Unit I sediments or were uplif ted and stripped of Upper Unit I sediments prior to deposition of Unit II sediments.
- 8. Fine sediments of Unit II are characterized by varicolored to gray-green waxy clays throughout the study area to the south and west of the Southeast anticline. This suggests that:
- a. The area to the south and west of the Southeast anticline was the site of deposition of very fine-grained sediments during part of Unit II time, and
- b. These-sediments reflect low energy environments or that source areas were providing only fine- ,,g grained sediments during this time.
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L- S/HNP-PSAR 12/31/81 .I 9 Sands and gravels of Unit III intricately interfinger throughout the study area. This is interpreted to mean thats
- a. The sediments of Unit III demonstrate the lateral and vertical variations and changes in deposition of sands and gravels in a fluvial environment, and
- b. Rapid lateral and vertical changes occurred in the fluvial conditions of the Pasco Basin during Unit III time.
- 10. Each of the four units recognized in the Ringold commonly. commences with gravels or coarse-grained sediments and ends with silts and clays with a complex 1y interbedded sequence of silts, sands, and gravels present in any one core or drillhole where the entire unit is present. Each of the four units is interpreted to:
- a. Represent a major cycle (with subcycles) of deposition in the Pasco Basin,
- b. Represent a time period when more sediment was introduced into the basin than could be passed through or a time of general subsidence, and
- c. Reflect fluctuations in the amount and size of sediments introduced into the Pasco Basin or to tectonic pulses above, in, or below the outlet of the Pasco Basin.
- 11. Ringold units are well-defined in both the inter-pretive lithologic and geophysical logs and unit contacts are flat-lying throughout most of the Site area, suggesting tectonic stability during or until late in Ringold time.
- 12. Parts of the Ringold which might be expected to be present in drillholes 55, 90, 99, 101, 102, 109, and 110 are absent. In these drillholes, as throughout most of the study area, the Pre-Missoula Flood Gravels overlie the Ringold Formation. This suggests'that:
- a. A channel in post-Ringold time was cut across the-Southeast anticline, removing parts of the Ringold Formation, and
- b. The Pre-Missoula Flood Gravels unconformably overlie the Ringold Formation.
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- 13. Pre-Missoula Flood Gravels are present throughout most of the study area, with the exception of the a northwestern part of the Southeast anticline. This is interpreted to mean that the Southea'st anticline was a structural high during Pre-Missoula time and
.was not completely covered by the Pre-Missoula Flood Gravels.
- 14. The Missoula Flood Gravels are present throughout the study area, suggesting that the Missoula Floods were extensive and covered the Southeast anticline.
6.2 STRUCTURAL FEATURES AND HISTORY 6.2 1 SOUTHEAST ANTICLINE AREA The Southeast anticline, the easternmost segment of the Um tanum Ridge / Gable Mountain structural trend, is a sub-surface structure buried beneath the glaciofluvial gravels. The top of basalt structural contour nap (Figure 2R-7) shows that the Southeast anticline trends northwest, plunging southeast, for most of its length. Near the southeastern end, its trend turns easterly or slightly north of east. Initial deformation of the basalts in the vicinity of the Southeast anticline commenced in post-Esquatzel Member time (older than 12.0 million years B.P. ) and cortinued intermit-tently through upper Elephant Mountain Member time (10.5 million years B.P. ) as reported by Myers and Price (1979). The area was then subjected to a period of subaerial weathering which resulted in the development of a residual clay paleosol on the upper part of the Elephant Mountain flow. Parts of the B- and C-horizons of this paleosol are present in drillholes 3, 101, 102, 103, and 125. Ringold units thin along the flanks and across the Southeast anticline. Where a complete Ringold sequence is not present, geophysical and lithologic markers are more subtle, and correlations are less certain. These correlations are dashed and questioned on the maps and cross-sections. On the northeastern side of the Southeast anticline, four generally fining-upward sequences are recognized in the sediments, although few gravel beds are present. Because definite correlations could not be made with the Ringold units defined on the southwestern side of the anticline, units and contacts on the northeastern side of the anti-cline are questioned in the cross-sections. 2R-28 Amendment 23
S/HNP-PSAR 12/21/81 Basal . Unit I gravels are present to the southwest of the Southeast anticline area. They thin, pinch out, or have been removed by erosion across the anticline, suggesting that the structure was a positive area during Basal Unit I time. The Basal Unit I gravels are not present on the northeastern side of the structure. Structural and topo-graphic relief on the Southeast anticline must have been low during Basal Unit I time or the clay paleosol on top of the basalt would have been removed by erosion. Uper Unit I fine-grained sediments thin across the south-eastern part of the Southeast anticline. The northwestern part of the cre=t of the structure lacks Upper Unit I sediments, suggesting that this part of the structure was either a positive area during Upper Unit I time or that post-depositional erosion removed the sediments. The presence of the paleosol at the top of Upper Unit I sediments across the southeastern part of the Southeast anticline indicates landscape stability in late Unit I time for the Southeast anticline area. Minor erosion of Upper Unit I sediments is interpreted in the vicinity of drillhole 99 on the southeastern end of the structure. Within the Southeast anticline area, Unit II sediments are unconformable above Unit I, thin at least 132 feet toward the Southeast anticline, and are interpreted to cross the southeastern part of the structure. The gravel horizon occurring to the southwest in the lower part of Unit II pinches out toward the anticline. The varicolored and gray-green waxy clays common in the upper parts of Unit II in the southern and central parts of the study area are not present over the Southeast anticline. Loss of the basal gravels and waxy clays and thinning of Unit II sediments over the Southeast anticline suggests that the structure was a positive feature during Unit II time, some uplift and erosion could have occurred following deposition of these sediments. Channeling of Upper Unit II fines in the vicin-ity of drillhole 99 is believed to have occurred. Probable dune sand and find-grained fluvial sediments at the top of Unit II show no evidence of the development of a paleosol. Units III and IV both thin toward the flanks but do not cross the crest of the Southeast anticline. Such behavior may be a result of erosion or non-deposition, and it is here interpreted that the Southeast anticline was a positive area during Units III and IV time. Glaciofluvial sediments of the Pre-Missoula Flood Gravels unconformably overlie the Ringold across the Southeast an ticline.' Their presence, however, is uncertain over the northwestern part of the structure along Line 3 in drill- ' holes 37 and 38 (Figure 2R-20). In the vicinity of 2R-29 Amendment 23
S/HNP-PSAR 10/14/82 drillholes 54, 55, 68, 99, 101, and 103, Pre-Missoula Flood Gravels are noted to fill a channel cut into the Ringold sediments. Missoula Flood Gravels unconf ormably overlie the Pre-Missoula Flood Gravels throughout the Southeast anti-cline area, and surficial dune sands and fluvial deposits of Recent age are present over most of the area today. No def ormation of any of the pcst-Ringold sediments is recog-nized in the southeast anticline area. A fault was recognized on the southwestern flank of the Southeast anticline (Figure 2R-7) on the basis of fault brec-cia and an anomously thick section of the Elephant Mountain ! member in corehole 125. A study carried out by Golder Asso- { ciates (1982) for Washington Public Power Supply System J determined the attitude, displacement and capability of this fault. Eleven drillholes, spaced 30 to 100 feet apart, indi-cate that the f ault has a reverse sense of movement, strikes N390W and dips 300SW. The range of vertical displacement on the f ault is 35 to 60 feet, and the range of dip-slip displacement is 70 to 110 f eet. Based on this small amount of displacement, the Souteast anticline fault is interpreted to be a minor f eature which probably does not extent any significant distance away from corehole 125. Four strati-graphic contacts across the projection of the fault plane (Elephant Mountain basalt /Ringold Upper Unit I contact, the contact of a lower fine-grained and upper coarse-grained subunit of Ringold Upper Unit I, Ringold Upper Unit I/Rin-gold Unit II contact and Ringold Unit II/ Pre-Missoula contact) showed no abrupt changes in elevation. Based on these observations, the Southeast anticline fault has not been active for approximately 10 million years. It has clearly not been active since Pre-Missoula time (730,000 years bef ore present) and is, theref ore, not capable. 1 Based upon the similarity of structural patterns in the ' cross-sections, structural contour, and isopach maps, and l the amount of thinning of stratigraphic units displayed in these illustrations, the Southeast anticline is interpreted to have developed intermittently throughout Ringold time. Def ormation may have been most intense during Unit II and Unit III time and diminished during Unit IV time. 6.2.2 MAY JUNCTION AREA The May Junction area includes the May Junction monocline and the area between the monocline, the Southeast anticline, and the Site area. The north-south-trending May Junction monocline is defined by the eastern boundary of a gravity high associated with the Gable Butte / Gable Mountain segment of the Umtanum Ridge / Gable Mountain structural trend (Weston 2R-30 Amendm 8
S/HNP-PSAR 10/14/82 Geophysical Corp., 1981b). Relief on this f eature is approx- i imately 300 feet, with a slope of 10 degrees or less on the $E basalt surf ace. To the east, a gentle southward-slipping (less than 1 degree) surf ace forms the northern flank of a southeasterly-plunging syncline. The Ringold Formation thins over the basalt high to the west of the May Junction monocline as shown on the isopach map (Figure 2R-18) and the cross-sections (Figures 2R-22 to 2R-24). Because a complete stratigraphic sequence of Ringold sediments is not present, correlations over this structure are questioned. Gravels of Basal Unit I are present throughout the area except where they pinch out or have been removed by erosion on the flank of the Southeast anticline and over the -northern part of the May Junction monocline on Line 8. The interpretation that the Basal Unit I gravels overlie the structure on the southwestern end of Line 3 suggests that deformation of this structure occurred after the deposition of the gravels. Upper Unit I fine-grained sediments in the May Junction area are interpreted to thin or interfinger with a thickened gravel interval in the southwestern part of the area. A normal sequence of Unit II sediments is present in the eastern part of the May Junction area. To the southwest (Line 3) the gray-green waxy clays become varicolored. These sediments generally thin toward the May Junction mono- ' cline and are interpreted to pinch out or have been removed by erosion over the northern part of the structure in the $9 vicinity of Lines 8 and 8C. Unit III and Unit IV sediments i are interpreted to be present only on the flanks of the mono-cline. The absence of Units I through IV could be a result of erosion or non-deposition. Pre-Missoula and Missoula Flood Gravels overlie the Ringold sediments. The shallow and unif orm dip of the sediments and basalt units across the May Junction monocline, and the generally uniform and typical thickness of the Elephant Mountain member and Rattlesnake Ridge interbed encountered along Line ! 8 and 8C, indicate that the May Junction monocline is not i fault controlled. The shallow dip of stratigraphic units (7 to 10 degrees) indicates that, although the monocline is a [$$ i prominent geophysical f eature, only minor def ormation has L taken place in the basalt or overlying sediments along the ! trend of the monocline. This minor deformation has clearly been accommodated by the warping which produced the mono- ; cline. It is postulated that def ormation of the May Junction monocline and f old commenced in post-Elephant Mountain Member time (less than 10.5 million years B.P.) and probably y o 2R-30a Amendment 2
S/HNP-PSAR 10/14/82 diminished in Unit IV time (early Pliocene). No deformation is recognized in the post-Ringold sediments in the May Junction area. 6.2.3 SITE AREA The structural contour map on top of basalt in the Site area (Figure 2R-7) indicates that the basalt surf ace underlying the Site area is of generally low relief, with typical slopes on the order of 1 degree or less. The relief on the basalt surf ace is interpreted to be the result of gentle f olding which has produced three dominant f eatures. These are the Cold Creek syncline in the southern part of the Site area, an unnamed gentle east-west trending anticline in the i c'
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2R-31 Amendme 8 l
S/HNP-PSAR 12/21/81 central part of the Site area, and a syncline along the northern edge of the Site area. # The Cold Creek syncline trends northwest and plunges gently to the southeast through the Site area (Myers and Price, 1979). A local depression occurs along the axis of the syncline in the vicinity of drillhole S-16. The bedrock surface in the lowest portion of this depression is approxi-mately 150 feet below the surrounding bedrock surface. The syncline is asymmetrical, with the steeper southwestern limo formed by a northwest trending flexure in the Site area (Weston Geophysical Corp., 1981a). The maximum slope on the southwestern flank of the syncline is approximately 5 degrees. Along Line X-1 (Figure 2R-28), which generally parallels the axis of the syncline, Ringold Units I through III maintain a constant thickness and parallel the basalt surf ace ; however, the upper fine-grained part of Unit IV is thinner in drill-hole S-17 than elsewhere on Line X-1. This reduced thick-ness is due either to erosion or non-deposition and suggests uplift of the basalt underlying the Ringold section in this area during or after the deposition of Unit IV sediments. Ringold Units III and IV are interpreted to be absent in drillhole S-24 on Line 4D (Figure 2R-26) on the southwestern flank of the Cold Creek syncline. The absence of these units suggests similar uplift and erosion after Unit II time and possibly during or af ter Unit IV time. A small, generally east-west trending anticlinal feature occurs on the bedrcck surface on the northern limb of the Cold Creek syncline. The relief across this flexure is 250 feet on the southern flank and 100 feet on the northern flank, with the northern flank sloping more steeply (maximum of 3 5 degrees). The Ringold formation is warped over the anticline, and the upper, fine-grained part of Ringold Unit IV is thinner over the structure along Line 1 (Figure 2R-25), Line M (Figure 2R-27), and Line W (Figure 2R-28). The reduced thickness of Unit IV may be interpreted to suggest that upwarping of the anticline and consequent thinning of Unit IV by erosion or non-deposition occurred during or shortly after Unit IV time. With the exception of drillhole S-24 on Line 40, the entire Ringold section is present in the Site area. Thinning or elimination of Unit IV occurs only over bedrock highs, suggesting that deformation in the Site area occurred during or after Unit IV time (early Pliocene). Uplift and erosion along Line 4D clearly occurred af ter Unit II time, probably during or after Unit IV time, to be consistent with the time of deformation of the surrounding structures. No deforma-tion is recognized in the post-Ringold sediments which are present throughout the Site area. y 2R-32 Amendment 23
S/HNP-PSAR 10/14/82 REFERENCES-Brown, R. E., and Brown, D. J., 1961, The Ringold Formation and its relationship to other formations: HW-SA-2319, General Electric Co., Richland, WA. Clague, J. J., Armstrong, J. E., and Mathews, W. H., 1980, -Advance of the Late Wisconsin Cordilleran ice sheet in southern British Columbia since 22,000 Yr B.P.: Quat. Res., vol. 13, p. 322-326. Collinson, J. D., 1978, Alluvial sediments, in Sedimentary environments and f acies (H. G. Reading, ed.): Elsevier, N.Y., p. 15-60. Fulton, R. G., and Smith, G. W., 1978, Late Pleistocede stratigraphy of south-central British Columbia: Canadian Jour. of Earth Science, vol. 15, p. 971-960. Golder Associates, 1982, The Southeast Anticline Fault: gr Evaluation of Attitude and Displacement. Report prepared $k for Washington Public Power Supply System. Gustafson, E. P., 1978, The vertebrate faunas of the Pliocene Ringold Formation, south-central Washington: Bull. of the Museum of Natural History, Univ. of Oregon, no. 23. Holden, G. S., and Hooper, P. R., 1976, Petrology and chemistry of a Columbia' River basalt section, Rocky Canyon, west-central Idaho: Geol. Soc. Amer. Bull., vol. 87, p. 215-225. Hooper, P. R., Reidel , S. P., Brown, J. C., Holden, G. S., Kleck, W. D., Sundstrom, C. E., and Taylor, T. L., 1981, Major element analyses of Columbia River Basalt Part I: Wash. State Univ., Dept. of Geology Open file rept. Leopold, E. B., and Nickmann, R., 1981, A late Miocene pollen and spore flora f rom the Hanf ords Reservation, eastern Washington: Rept. to Golder Associates. McDougall, I., 1976, Geochemistry and origin of basalt of the Columbia River group, Oregon and Washington: Geol. Soc. , Amer. Bull., vol. 87, p. 777-792. l McKee, E. H., Swanson, D. A., and Wright, T. L., 1977, Duration and volume of Columbia River basalt volcanism, Washington, Oregon, and Idaho: Geol. Soc. Amer. Abstracts with Programs, vol. 9, no. 4, p. 463. b
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2R JS Amendmen6 28 n- .-,n n ,_a w - ~ - - , ,-~~--,7 ,-
l S/HNP-PSAR 10/14/82 Mullineaux, D. R., Wilcox, R. E., Ebaugh, W. F., Fryxell, R., and Rubin, M., 1977, Age of the last major scabland flood of eastern Washington, as inf erred f rom Associated ash beds'of Mount St. Helens Set S: Geol. Soc. Amer. Abstracts with Programs, vol. 9, no. 7, p. 1105. Myers, C. W., and Price, S. M., 1979, Geologic studies of the Columbia Plateau: PHO-BWI-ST-4, Rockwell Hanford Operations, Richland, WA. NTIS, 1975, Well logging manual: prepared for U. S. Geol. Survey, by Scientific Software Corp., PB-247 641. Packer, D. R., and Johnston, J. M., 1979, A preliminary investigation of the magnetostratigraphy of the Ringold Formation: RHO-BWI-C-42, Rockwell Hanf ord Operations, Richland, WA. Pirson, S. J., 1963, Handbook of well log analysis: Prentice-Hall Inc., Englewood Cliffs, N.J. Shaw, H. R., and Swanson, D. A., 1970, Eruption and flow rates of flood basalts, in Proceedings of the Second Columbia River Basalt Symposium: Eastern Wash. State College, p. 271-299. Swanson, D. A., Wright, T. L., and Helz, R. T., 1973, Linear vent systems and estimated rates of magma production and eruption for the Yakima Basalt on the Columbia Plateau: Amer. Jour. Sci., vol. 275, p. 877-905. Swanson, D. A., Wright, T. L., Hooper, P. R., and Bentley, R. D., 1979, Revisions in stratigraphic nomenclature of the Columbia River Basalt Group: U. S. Geol. Survey, Bull. 1457-G. Tallman, A. M., Fecht, K. R., Marratt, M. C., and Last, G. V., 1979, Geology of the separation areas, Hanf ord site, south-central Washington: RHO-ST-23, Rockwell Hanford Operations, Richland, WA. Waitt, R . 13 . , J r . , 1980, About forty last-glacial Lake Missoula jokulhlaups through southern Washington: Jour. of Geology, vol. 88, p. 653-679. Weston Geophysical Corp., 1981a, Geophysical investigations, Skagit/Hanford Nuclear Project Site, Hanford Site, Washington, Appendix 2L: Northwest Energy Services Company, Kirkland, WA.
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S/HNP-PSAR 10/14/82 TWeston Geophysical Corp., 1981b, Geophysical investigations of the Gable Mountain-Gable Butte area, Appendix 2K: Northwest Energy Services Company, Kirkland, WA. Wright, T. L., Grolier, M. J., and Swanson, D. A., 1973, Chemical variation related to the stratigraphy of the Columbia River basalt: Geol. Soc. Amer. Bull., vol. 84, p. 371-386. Wright, T. L., and Hamilton, M. S., 1978, A computer-assisted-graphical method for identification and correlation of. igneous rock. chemistries: Geology, vol. 6, p. 16-20. Wright, T. L., Black, K. N., Swanson, D. A., and O'Hearn, T., 1980, Columbia River basalt, 1978-1979 sample data and chemical. analyses: U.S. Geol. Survey Open-file rept. 80-921. s W 2R-35
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AMENDMENT 28 T
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- ,C. .w. .
, i, sxAGiT i HANFORD NUCLEAR PROJECT y- .e:.. ,
. . - .. ^- PREUMINARY SACETY ANALYSIS REPORT
. Drillhole in which green waxy DISTRIBUTION OF UNIT ll
'd Clay present in Unit il GREEN WAXY CLAYS FIGURE 2R-30 M "DMENT 28
10/15/82 DRILL HOLE 87 SAMPLE TYPE Page .l _ of ._3._ Project No : 803-1701H @ Cuttings Elevation : 513. 2 f t . 95 E Core, Number Indicates % Core Recovery Total Depth . 339 ft. Coordinates : N 453,790.15; . E 26 3,3 34. 42 C2015 O XRF. With Sample Number Date Completed : 9/18/80 Chemical Results Listed in Table 2R-1 Unit Column Refers to General Stratigraphic Divisions identified Within the Site Area: M - Missoula IV - Ringold. Unit IV Columbia River Basalt Group PM - Pre-Missoula Ill - Ringold. Unit til Tem - Elephant Mountain Member 11 - Ringold, Unit ll Ter - Rattlesnake Ridge Interbed I-u - Ringold. Unit 1-upper Tp - Pomona Member 1-b - Ringold. Unit I-basal B - Basalt. Undif ferentiated Elevation Depth c@ s\ t* Lithologic Description Unit (MSL) ( ft. )
- ogS 610 -
' *! Gravelly silty SAND. Light-olive-brown. Very-fine- to fine- and coarse d
(f.{k k to very-coarse-grained. Gravel 85% basalt clasts, y Silty sandy CRAVEL. 70% basalt clasts. Sand coarse- to very-coarse- i
-10 Ug/
. grained; angular to subrounded. l Sandy GRAVEL. 70% basalt clasts. Sand very-fine- to coarse-grained; 500 -_ 14 .. '
angular to subangular; 35% mafics. T 4.'*f i
-20 ),* Q-[
490 -- 2 .'. ** ;*.*. M 4, ..'.. 7
-30 7. ,
- Silty GRAVEL. 80-90% basalt clasts.
480 -- 3 1 ** 7 * * :f m Ll .t (
-40 1.*(.* 2 470 - ,
3 *,j'.f',k
, ;:3, .i.. Silty sandy GRAVEL. 80% basalt clasts. Sand coarse- to very-coarse-
-50 21;,'y.- (rained, some medium-( rained; angular to subrounded.
. p. , GraveTIy~ silty LTND.~ Fine- to very-coarse greined, mostly medium-460 - ,
i W?$ grained. 20% mafics. Silt adheres to grains. y y %.t Silty CRAVEL. 40% basalt clasts. Silt adheres to ct:sts. No cement. M
-60 450 -, 5 Silly sandy GRAVEL. 35% basalt clasts. Sand medium- to very-coarse. PM
,7[b,k.-
4O grained, fining downward; angular to subrounded; 20-30% mafics,
-70 decreas ng with depth. Silt adheres to grains. No cement.
440 - , [ Gh.-[ . { difij
-80 q l, i SILT. Yellowish-gray. Subrounded fragments.
430 - 3 il n l1 Sandy SILT. Yellowish-gray. Subrounded fragments. Sand very-7' I
~*O 2 fine grained.
420 - S3_ --y
-100 3EE
_,r 5 11 7 28 4 to - Q _]__._ Silty CLAY. Light-brown. Subrounded fragments.
" l
-110 F@J& @ l 400 - [* ._ F*y 120 390 - S _1 4 CLAY. Light-brown. Subrounded fragments.
3 p] Sandy CLAY to clayey SAND. Moderate-brown. Sand very-fine grained. [
-130 TT 7 1 4W 1 AW PUGET SOUND POWER & LIGHT COMPANY SKAGIT / HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE 97 p/. FIGURE 2R-A-59 AMENDMENT 28
10/15/81 DRILL HOLE MJ-1 EAMPLE TYPE Page 1._of _8 Project No : 823-1036 O Cuttings Elevation : 476.3 fe. 95 E Core, Number Indicates % Core Recovery Total Depth : 571.0 ft. CoorJinates : N4%1_649 11* F7Aa.611_?1 C2015[*,] XRF. With Sample Number Cate Completed : 9/15/82 Chemical Results Lised in Table 2R-1 Unit Column Refers to General Stratigraphic Divisions identified Within the Site Area : M - Missoula til - Ringold* Cycle ill 8 - Basalt, Undifferentiated PM - Pre-Missoula ll - Ringold, Cycle 11 EM - Elephant Mountain Member IV - Ringold. Cycle IV RR - Rattlesnake Ridge Interbed I - Ringold. Cycle i P - Pomona Member Elevation Depth k00 Lithologic Description Unit (f t.MsL) (feet) hemgo9*fo\
- 8
, Gravelly silty SAND. Light-olive-brown. Medium- to very-coarse-grained.
S )A}.8 gjc}o. 470 - ,- M 2, [* Cravally silty SAND. Olive-gray. Very-fine- to very-coarse grained, '
- 10 .r y fining with depth. 60 to 75% basalt grains. Angular to subrounded.
_ ::Q., JL,
..~
460 - lbo "
} -te n
- 20 v .f J.' jy Crave 11y silty SAND. Medium-dark-gray grading to medium-gray at 30 to 3 ., i
- .t 35 ft. 55 to 80% basalt grains, decreasing with depth. Very-fine- to very-coarse-grained. Angular to subrounded. Gravel 75% basalt clasts.
7 450 - A fM .i .,e P
~ 30 2 p.s _ _ __ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ __
, _ 7 Silty CRAVEL to gravelly SILT. Light-clive-gray. Ferruginous stain.
7 , p*qpq = q 3 Cravel basaltic; possibly caved. o .i k,
- 40 y a
{Q Crave 11y SILT to silty CRAVEL light-olive-gray. i,f i ..
; i 430 - Gravelly sandy SILT to silty sandy CRAVEL. Light-olive-gray. Spotty S q ${.j ,r
{ ferruginous stain. Sand very-fine- and medium- to coarse-grained.
.o
- 50 M;. :*'-
PM
,? ! $*
[ k *. '<.3* Silty sandy CRAVEL. 30 to 50% basalt clasts. decreasing with depth.
*C . Sand very-fine- to very-coarse-grained; mostly coarse- to very-coarse 420 - ,
j, . ;b? grained; 20% basalt grains, h .,
- ' . }.'-
.y;..$. ."
- 60
~
7 . Gravelly SAND. Yellowish-gray. Fine- to medium-grained. 10% mafics.
*T.l Angular to subangular. Trace silt. g lM-4 , M
.e D,1 PUGET SOUND POWER & LIGHT COMPANY SKAGIT / HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-1 D FIGURE 2R-A-112 AMENDMENT 28
10/15/82 DRILL HOLE M'-1 Page 2_ of JL. D eth
- g Lithologic Description Unit 0-7 f"hk Sandy CRAVEL. 20% basalt clasts. Sand fine- to coarse-grained; 10 to 15%
'-i. ,y,M' * ..mafics; angular. Trace silt.
- 70 m
.jsf Gravelly silty SAND. Yellowish-gray to light-olive-gray. 20 to 25%
E ' mafics. Very-fine- to coarse-grained. Angular to subangular. v@t ~; l 400-
@b 2 .j .
crave 11y SAND to sandy CRAVEL. Yellowish-gray to light-olive-gray. Fine-to very-coarse-grained; mostly very-coarse-grained. 30% basalt grains.
- 80 &' *'#
f.e.j}; Crave 11y silty SAND. Yellowish-gray to light-olive-gray. Very-fine- to 2
..$p[:
;*;; .A{ . very-coarse-grained. Crain size decreases and sorting is poorer with deptt .
3 e ';If. 25 to 30% basalt grains. Silt increases with depth. 390- 7 1 Lp)
'eh1 s
~
- 90 &(s-1
{ ; Silty sandy CRAVEL to gravelly silty SAND. 45% basalt clasts. Sand as PM above. 380- Crave 11y silty SAND. Yellowish-gray to light-olive-gray. Very-fine- to b.!:.k i .* medium-grained; mostly medium-grained. 15 to 20% mafics. Local ferru-
-100 A dg ginous stain.
~
" ' ' .*f*. .Silty sandy CRAVEL. Matrix r above. Local ferruginous stain. No sandy
, ,}' j.' , cement rinds.
n 370. N Crave 11y silty SAD to silty sandy CRAVEL. Yellowish-gray. Very-fine-1, ,,.jf.,/
. .,' to coarse-grained. 10 to 15% mafics. No sandy cement rinds.
-110
- *e av e F. g .a.
D+****h Crave 11y SAND to sr.ndy CRAVEL. Yellowish-gray. Fine- to medium-grained. 3'ce 'h,Q, 7 to 10% mafics. Angular to subangular. Clean. Gravel 15% basalt 360- n clasts; no sandy cement rinds. n,,',w*y* ; %..
** *N?
-120 g, ,
s .i$gK) Sandy CRAVEL to gravelly SAND. Sand as above. Some pebbles with yellow Q';jg sandy cement rinds (reworked Ringold?).
$Q:v.t, q?g_&
350- E,IkAW 3 t+r M &g.N
-130 h;%%:
II: *? 2 ;. *I Gravelly SR'D. Yellowish-gray to dusky yellow. Fine- to medium-grained;
- ?gji{a mostly medium-grained. 7-10% mafics. Angular to subangular. Abundant
.L gravel clasts with yellow sandy cement rinds. IV 340- y diff my . '.; YJg.y.
-140 *ic yiy,
- Eit
~
' .. l.9
. e,Mj
~
8 MW PUGET SOUND POWER & LIGHT COMPANY WRE SKAGIT I HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-1 2R-A-112 AMENDMENT 28
10/15/82 DRILL HOLE C-1 Page J_.of tL_ Uj]f,'" (Depth e\ Lithologic Description Unit ust) feet) g,M c,t
- 330- ,._
l.,-h MY*.b.
;. 6. .t. Silty sandy CRAVEL. Matri.c yellowish-gray to dusky yellow. Sand fine- to
-150 medium-grained; mostly medium-grained; 5 to 7% mafics; angular to sub-h.Jf
,.p*k.h
,. A angular. Yellow sandy cemeat rinds on gravel clasts.
fi ',% ' 4 320- , . ,- 7 ,
& % ~ .L :. .
.2* Crave 11y SAND. Yellowish-gray grading downward to dusky yellow. Very-
-160 *]:,' . fine- to medium-grained; mostly medium-grained. 5 to 7% mafics. Angular y *; _ to subangular. Abundant yellos sandy cement rinds.
i ?:' , . a e-310- - 1 f } (. Silty SAND. Yellowish-gray to dtsky yellow. Very-fine to medium-grained;
. e. mostly fine- to medium-grained. $ to 7% mafics. Trace gravel, yy
-170 .
1f Ik Silty SAND to sandy SILT. Dusky yellow. Very-fine-grained. td i I,: 300- 7 ,- u
-180 2 -.V
_b . SAND. Yellowish-gray. Fine- to medius-grained; mostly medium-grained.
, 7 to 10% mafics. Angular to subangular. Trace silt from 180 to 190 ft.
290- ,
'. .x . , Micaceous at 185 to 190 ft. and 195 to *OO i ft. Trace gravel with yellow a sandy cement rind at 195 to 200 ft.
f'Q.}
-190 <
~
T .
,3 w
. =
280- [
;.c.>
- 200 m. - . ..
-y.$.*f' < Sandy CRAVEL to gravelly SAND. Yellowish-grsy to dusky yellow. Abundant 1 yellow sandy cement rinds.
.J7.M W~.* v e, , y 270- #
{ ,k ' # -,Q Crave 11y SAND. Dusky yellow. Local ferruginous stain and cement.
' *W'
- 210
'.r.
i . . .* e t' Gravelly SAND. Light-olive-gray. Fine- to medium-grained; mostly 2 *- medium-grained. 15 to 20% mafics. Wood fragments. Micaceous. Sandy g[*Jd, - cement rinds. 260- y ; SAND. Light-olive-gray. Very-fine- to medium-grained; mostly medium- g 1 grained. 20% mafics. Micaceous.
-220 h* *. *.
- p . , . * , *, CRAVEL. Trace sand. 15 to 20% basalt clasts. Trace sandy cement rinds. g
.*M i
ki
, ,. (V c sc 1 PUGET SOUND POWER & LIGHT COMPANY LOG OF MILL HOLE W 1 D' FIGURE SKAGIT l H ANFORD NUCLEAR PROJECT 2R-A-112 AMENDMENT 28
DRILL HOLE MJ-1 Page_i _ of _8_
- D th g
- sc Lithologic Description Unit 250 - I* ***' * '
[ * , * * * . ,CRAVEL, **,- as above. Pyrite on some clasts.
- 230 W *
- 2.*.) Sandy CRAVEL. 35% basalt clasts. Local pyrite. Minor yellow sandy m 1 ,*.*.*.*.?, cement rinds. Sand matrix fine- to medium-grained.
',.* Z%',
240 - J % Crave 11y sandy SILT, with CLAY and ash-like fragments. Very-light-gray, 3 D ' T,1 olive-gray, and light-clive-gray. Gravel and sand probably caved. Pyrite fragments. Some silt and clay fragments laminated.
-240 1 i*t
_ 11 g g' .______.__ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ c, n,.gf b.3,'e 230- ,, O
).M Crave 11y silty SAND, with CLAY fragments. Light-olive-gray. Very-fine-to medium-grained.
~ f .
- w:- f:;DM
. ..: e 220 - % ;: SAND, with clay and white ash-like f ragments. Yellowish-gray. Very-fine 2 ].y
;.e(: -
to fine-grained. Mostly fine-grained. 5 to 7% mafics. Trace gravel.
- 260 y I y04e'
. Gravelly silty SAND with SILT fraguents. Yellowish-gray. Very-fine- to medium-grained. 10% mafics. Angular to subangular.
L'g - 210- - R s -:yYI:. : jik3
-270 j Gravelly sandy SILT to CLAY. Yellowish-gray. Slight waxy luster to clay.
g@
~ ,.
11 200 Gravelly sandy SILT to gravelly silty SAND. Yellowish-gray. Sand 7 t
-280
]* ' * , t g, very-fine-grained.
l*g )*h Crave 11y silty SAND. Yellowish-gray. Very-fine- to fine-grained;
} . dc 'M mostly very-fine-grained. 3% mafics. Angular to subangular.
e.. ,,. nt l$ 190 -
,. I_ Silty SAND, with CLAY f ragments. Dark yellowish-brown. Sand as above.
S '-:.
- 290 O-H -
...c3.
., ? .;
- .9 Silty SAND, with silty SAND to sandy SILT fragments. Yellowish-gray.
Very-fine- to medium-grained. 2 to 3% mafics. 180- lib:
- 300 I
- j'ig
~~ b
{ ?.x3.[ Crave 11y silty SAND, with CLAY fragments. Sand yellowish-gray. Clay dark-yellowish-brown. Very-fine- to medium-grained. g
.. _ u M.L T' PUGET SOUND POWER & LIGHT COMPANY FIGURE SKAGIT / HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-1 2R-A-112 AMENDMENT 28
1 10/15/82 l DRILL HOLE M-1 Page_i._ of E_
'D th e go Lithologic Description Unit 170 - 45 Gravelly SAND, with dark yellowish-brown CLAY fragments. Yellouish-gray.
5 QQ. Fine- to coarse-grained;mostly medium-grained. 3% mafics. ,,_,
- p* 5
- 310
_ p. . ... y a W '.ati 1"s:Crave 11y silty SAND, with silty clayey sand fragments. Light-olive gray.
.ZE Very-fine- to medium-grained; mostly fine-grained. 2 to 3% mafics.
160 - y [d y'%
- f Angular to subangular.
2
- 320 EY-Q.
m . 1 Sandy clayey SILT. Olive-gray. _ wi .,
--e - 1-u Crave 11y clayey SAND. Olive-gray. Medium- to coarse-grained,
{ar ,s[ 5 ::
- 330 A y .g a : Cravelly silty SAND, with SILT and CLAY fragments. Light-olise-gray.
g .. f Very-fine- to coarse-grained. 3% mafics. Local ferruginous stain.
?L.?N 140 - , 3*
- Crave 11y SAND, with SILT fragments. Light-olive-gray. Tine- to medium-U:.l..;,y( [.- grained;. ) ' mostly medium-grained. 5% mafics. Local ferruginous stain.
. a: %;
- 340
?
l 7' SAND. Light-olive-gray. Medium-grained. 5 to 7% mfalcs. Micaceous. 4: $.'o] Trace gravel. I 130 -
^
h
*. a.*'ay*,4 Sandy CRAVEL. 20% basalt clasts increasing dos 1 ward to 40 to 45% basalt
. 350 ."..' l a *. . clasts. Some sandy cement rinds. Blue cant to some basalt clasts. Local
-* * * ' ferruginous stain and cement.
7 ': i,* =#h**.. *
..*'R.fi.
r
~
N.; a' 5 120 - 5 ,,..... *:
.4
****f
-360 *. .* .*. *. ..
T *.*..*
^
- CRAVEL. Trace sand. 30 to 40% basalt clasts. Sandy cement rinds.
".*.*'[.**Blue cast to some basalt clasts.
1-b 110 - I '. I.*-
.. 6.[;
-370 . .* * . .
2 . ..~... -
*..;*.)..
~
a . ;, y' 100 - h*p Silty sandy CRAVEL. 30 to 40% basalt clasts. Sand very-fine- to medium-
+ : t , ly,z grained; yellowish-gray.
-380 3l .',W e
fMe -T lfl.*/ Basalt. Dark-gray. Caved gravel clasts. , Jem m . t. PUGET SOUND POWER & LIGHT COMPANY LOG OF DRILL HOLE MJ-1 \ FIGURE SKAGliI HANFORD NUCLEAR PROJECT 2R-A-112 AMENDMENT 28
10/15/82 DRILL HOLE M-1 Page_.ft of E _ D th td
- sc Lithologic Description Unit 90-
}; ., ,lf,'*- *,.,. ,
BASALT as above. Some vesicles.
-390 ,,.a....;
$ -l./.'.
'. .: *. .. s..-,
80- . -****
* * .1 BASALT. Dark-gray. Weathered. Vesicular. Some vesicles filled with e green and white clay.
- 400 2
.:, . .'.' ' *.a *
,'i.
*. 9 ..
S.' .. .
...* . - =
70- , . . . .' *' 3 <.., , . r-410 ' , *,;** , , BASALT. Dark-gray. Vesicular. Moderately fresh. Some caved gravel.
,,..a.,.
L .*.. e l , *, . 3 ./,.;l.~. ; 60-
-420 '.' ," ,c, * ,, j BASALT sand. Grayish black. Fresh. Ground to sand size by drill bit. Tem 7,'/*,a',*
, ' t . ,-
50- 7,-l* w
!....a',.a,',' i
~'
- 430 BASALT. Brownish-gray to grayish black. Fresh. Trace vesicles. Local
'.S,*.,*. pyrite mineralization at 430 to 435 ft.
_ ,, y , , ,, , 2 ,...*. 40-i .*.*,*,*. . BASALT. Dark-gray to grayish black. Fresh. Nonvesicular.
'.,4 ,
,g.=,
-440
- s'... , ! ,
s .,* 4 . .
.*,a,'.*, BASALT. Olive-gray to olive-black. Vasicular. Some vesicles filled with
'.,.;.',,* green clay. Some brecciated clay fragments.
30- X
*,,' . " * , BASALT. Dark-gray. Fresh. Nonvesicular. Trace silt from 450 to 460 ft.
-450 , ';. -* * .
7..:. A' , * , . . * . 20- '** q w,= ,.<,*'.' .
. . .,a. .
. *' . = .
-460 -
4 ;.? . ' 3L,.*'.*,' BASALT. Olive-gray. Fresh. Trace silt. Nonvesicular. W a ,* , , -a , - .
;- . . , - g _._
g, y *
- FIGURE PUGET SOUND POWER & LIGHT COMPANY LOG OF DRILL HOLE MJ-1
- SKAGIT l HANFORD NUCLEAR PROJECT 2R-A-112 AMENDMENT 28
' ; * } .; % % ' . a+ ~ .+ *
~
, . ,m, ~:.! .:
+
. ..; / ,e.s- f ik(.xwE. '-.
c . 2 . . < .. - am"W.1
- ..o.~D '. ..- ,'. .
++
- 5. *: . ,
. . ' . 3 'er 7
- 10/15/82 DRILL HOLE KY-1 Page 2 otB _
Depth eve o sc Lithologic Description Unit 10 - - S l' ' . * , * [, BASALT as above. Local calcite mineralization at 465 to 470 ft.
- 470 1 ; . /,
I
, ,a.
,a .. -
*,,4 .
0- 'l
- s '
p '*.e.,- W d .
- 480 ,*.*-
*... . Tem
{,**.,.,. .
~
, ' . *' *I .
1; .' .~. S'/,*,**,,
- 490 **.....
..,a..
*..? 4 i
,.*...* I.c.,
- *** ,'0
* * *, I /
{, ' , ' , * , * . ' IBASALT. Olive-gray. Moderately weathered. Vesicular. Vesicles filled /
' ,...,- * -
- Iwith yellowish-green clay. /
-500 h'a ' ,
, W Sandy clayey SILT to sandy silty CLAY. Light-alive-gray.
M yr~~[~
.. Clayey silty SAND. Light-olive-gray. Local pyrite cement. Very-fir.e- to i medium-grained. Angular to subangular.
- 510 4%
..G. :
- 1. >
.c .
, _ .f SAND. Light-olive-gray to yellowish-gray. Fine- to coarse-grained; Ter 3 mostly coarse-grained. 3 to 5% mafics. Angular to subangular.
-520 ,
5 ., TO SAND. as above, with pinkish-gray to light-greenish-gray CLAY fragments. [g.
-- ;..f
~
- 530 ,I . ' .
~ ~ - - ~ ~ - - - - - - - - - - - ~ ~ ' - - - - - - - -
g . ' [q. SILT. with CLAY fragments and SAND. Light-alive-gray; pinkish-gray pl and light-greenish-gray. Silt tuffaceous. Clay with waxy luster.
.3 M, :
p * * , .' . ' . ,
$ * .' .' J l BASALT. Brownish-black. Highly vesicular. Many vesicles filled with
-540 ,
clay. Caved sand. silt, and clay fragments Tp S :.:.:. ~ /
+ 1.-
..n., . .._ .
e p y.< PUGET SOUND POWER & LIGHT COMPANY FIGURE SKAGIT I HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-1 2R-A-112 AMENDMENT 28
10/15/82 DRILL HOLE - m-1 Pcwk of _fL U*
- g th *
[ Lithologic Description Unit 5 . .,, a i.,a, a
- 550 *."a'."a BASALT, as above.
, [.,* , [ .
2
.:)::.
! ."{G Sk .*a.. * *. ' '
a ,. p69
* * ' Tp
-560 , . . ff, g . , *..s. . <
,,,,, BASALT. Dark-gray. Fr_sh. Nonvesicular from 560 to 570 ft. Minor e.*6-vesicles at 570 to 573 ft.
S . , , ,, ,* . ses. <
-570 ! ' * ".** '
7***.,.,
-96.7- * **-
E0H 573' 6 m m 6 m W 6 6
-. ~
PUGET SOUND POWER & LIGHT COMPANY FIGURE LOG OF DRILL HOLE MJ-1 SKAGIT / HANFORD NUCLEAR PROJECT 2R-A-112 AMENDMENT 28
10/15/82 DRILL HOLE m> SAMPLE TYPE Page1 of 6L Project No : m -1036 , Cuttings Elevation : 470.2 ft. 95 - Core, Number indicates % Core Recovery Total Depth
- 425 ft.
* * * "*D*'
Coordinates : W 1 al? 49' NM" Chemical Results Listed in Table 2R-1 Date Completed : oN" Unit Column Refers to General Stratigraphic Divisions identified Within the Site Area : M - Missoula lit - Ringold. Cycle Ill B - Bast.lt, Undifferentiated PM - Pre-Missoula EM - Elephant Mountain Member 11 - Ringold. Cycle 11 RR - Rattlesnake Ridge Interbed IV - Ringold. Cycle IV I - Ringold. Cycle 1 P - Pomona Member Elevation Depth g@ s\ b* Lithologic Description Unit (f t.MSL) (f eet) 99 470-7 l4.J. ,pg.y Gravelly silty SAND. Medium-light-gray. 75% basalt grains. Coarse-t o!Xy:fi to very-coarse-grained. Ff } o., [ Crave 11y silty SAND to silty sandy CRAVEL. Medium-light-gray. 75% 1p[* basalt grains. Coarse- to very-coarse-grained. 460-- 10 ..
; ,)
7
~ ]*s .
e Gravelly silty SAND. Medium-light-gray. 75% basalt grains. Medium- to very-coarse grainel; mostly medium-grained. M
~_
gP4 y Jg***@ Crave 11y sandy SILT. Medium-gray. Gravel 60% basalt c1&sts. 450-- 20 h 7 SAND. Medium-dark-gray. Medium- to very-coarse-grained; mostly coarse-
- g:1
;.4 f,
' grained. 70% basalt grains. Trace silt.
n
, }bf:)
&dj 440-- 30 [n$ e. Gravelly silty SAND. Moderate yellowish-brown grading downward to
, ,, r,1 yellowish-gray. Moderately well to poorly sorted. 5 to 10% mafics, d 3g increasing with depth. Micaceous. Angular to subangular.
~
4: oc k _3, O. w .[. ^ j 430-- 40 , , e ,e' -# 4 A _ _ } f-
-_ br/:[ Crave 11y SAND. Yellowish-gray. Very-fine- to fine-grained. 5-72
'] .;g mafics. Angular to subangular. Gravel 20% basalt clasts. Trace 7 J. ?g.,, . silt at 45 to 50 ft. p3
^
c 18 -1 s: : : a.. 420--- 50 y 3y 's Crave 11y silty SAND to silty sandy CRAVEL. Light-olive-gray. 10 to 15%
,8g gjj mafics. Fine- to coarse-grained. Gravel 25 to 30 % basalt clasts.
__ hez 5 Silty sandy GRAVEL. Moderate olive-brown. No cement rinds. Silt
.=;, yT.' adheres to clasts. Sand fine- to medium-grained.
p. 410-- 60 .
? Gravelly silty SAND. Dark yellowish-brown. Fine- to medium-grained.
15% mafice. Silt adheres to grains. Subangular to subrounded. g]
+j,}y. i . #, .
%~ ,i PUGET SOUND POWER & LIGHT COMPANY f FIGURE SKAGIT f HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-2 2R-A-113 AMENDMENT 28
10/15/82 DRILL HOLE _ m-2 page2_ o1_ft E'* g
,"* th
- go Lithologic Description Unit lth:k
.** j Gravelly silty SAND, as above. Micaceous. Ferruginous stain. Fine-400--70 $- f to medium-grained; mostly medium-grained. No cement rinds on gravel i g.: clasts.
Ng _ MhD p3
-N Silty SAND. Dusky yellow. Very-fine- to medium-grained, mostly medium-3 [..] ?.fgrained. 5 to 7 % mafics. Large muscovite flakes.
MY!I 390-.- 80 g ,. Crave 11y silty SAND. Dusky yellow. Very-fine- to medium-grained; mostly 2 e(ka f,n!- t very-fine-grained. 2 to 3% mafics. No cement rinds on gravel clasts. h -M Gravelly clayey SILT to gravelly silty CLAY. Yellowish-gray to dusky f, 2[d VSY (i yellow. Gravel probably caved. 380--90 - Crave 11y SILT, with CLAY fragments. Yellowish-gray. Sand very-fine-b o! ]* t, grained. b SILT. with CLAY fragments. Yellowish-gray to 130 ft.; yellowish-gray [ 1 ;[b to dusky yellow from 130 to 140 ft. Trace gravel at 100 to 105 ft. 370--100 Clay fragments decrease with depth.
,,,.- H'[k, lit'l I
i '!! 360-- 110 j i
}
5 t
-~
'yl -
I17 , 1 l l 6a 350--120 - 2 3'fa _- ".h,,' g Yh d I 340--130 A I l _- LL ,' 1 u .. T l'f l 330--140 MLT g;
, SILT. Yellowish-gray to dusky yellow, 3 l ,
p __ g ., e: 8 PUGET SOUNO POWER & UGHT COMPANY i%. SKAGITl HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-2 %y' FIGURE 2R-A-113 AMENDMENT 28
1 1 , 10/15/82 l l DRILL HOLE M-2 Page_2 of L l 1 0 '" Depth po\ Lithologic Description Unit McL) (feet) M 08'
~
3 b.I 1jl l' Sandy SILT. Yellowish-gray to dusky yellow. Sand very-fine-erained. p .j Trace clay frarmente. 320--150 7 : 1 Silty SAND to sandv S11.T. Dusky vellow. Very-fine- to fine-g'ained r
" 2-3% mafics. Angular to subangul.ir.
O fu
.: e ..
hl'l*
._ /: $'
S (L. . ;)?
.Ts 310--160 .; : Silty SAND. Dusky yellow grading downward to light-olive-brown.
s-Very-fine- to medium-grained; mostly very-fine- to fine-graincd. 117 y i k.hj.f ; 3 to 5% mafics. Angular to subangular.
*; , }V. :..
{}:yg et-L.. f y [Ie.Q 300 -- 170 1-
- } _.. ig> Sandy SILT to silty SAND. Dusky-yellow. Sand very-fine-grained.
! .ma 1 i. f Clayey in part.
-- i.o i 7 Sandy SILT. Yellowish-gray. Sand very-fine-grained.
)l{f) m ,..
200--180 - - - - - - - - - - - - - - - - - - - - - - ....
, [: ?-
, Crave 11y SAND. Light-olive gray. Fine- to coarse-grained; mostly
__ 7. fine- to medium-grained. 15 to 20% mafics. Sandy cement dnds on 1-u?
. p.n.v : some gravel clasts. Trace silt at 185 to 190 ft.
2 ..-- 280- -190 ',~.9-
,gg,E Sandy CRAVEL to gravelly SAND. 45 to 50% basalt clasts. Sandy cement
" if rinds on some clasts. Sand yellowish-gray; mostly medium-grained; M$j-NZ*a'iL ?j 7 to 10% mafics.
Crave 11y SAND. Light-olive-gray. Medium-grained. Micaceous. Sandy z
'Q.~-
cement rinds on some gravel clasts. 1-b? 270-- 200 h,*[f . v';. Sandy clayey CRAVEL. Clay light-olive-gray; possibly weathered r
" %*V
...,, *e. *,;
basalt clay. __ x..
.,3 .. . - - - - - - - - - - - - - - - - - - - - - . - . - - . -
a *. BASALT. Olive-gray. Weathered and vesicular at 205 to 210 ft. N* , ' , * * * , ' 260 -- 210 f, .,' , . , 7'
,.**'. BASALT. Dark gray. Moderately fresh. Vesicular. Some yellowish-
. ' , ' . * , * ,green . clay in vesicles.
j Tem 4 7..... . f . m , 4 250-- 220 !.," *,'(( v . , . ., . . s
%::', :' .' 1
-- . , .e ,
lQ .
.= r J PUGET SOUND POWER & LIGHT COMPANY 't FIGURE LOG OF DRILL HOLE MJ-2 SKAGIT I H ANFORD NUCLEAR PROJECT 2R-A-113 AfiENDriENT 28
-n. 10/15/82 DRILL HOLE m-2 p.g..i_ of gu. 8 " Depth *\ Lithologic Description Unit usa u.sa + e s@' h-
. ...P,,*.... . ' .
;,.'.. e. ,*
j 240- -230 ',0 ,,., -* I 7
" '.f ,* /,*'
, BASALT. Medium-dark-gray to 255 ft. Weathered. Vesicular. Some
,...'... vesicles filled with yellowish-green to white clay.
\ ;';;*,*-
r ,*. :z, *i. 230-- 240 r .... 2 r,*',*. '. 7 . i.' .,. m
,4 , .. .. ...*
- 220--250
- a
-. * , . +
2 ".,.*..'- 1 I l g * , ' * * * , BASALT. **, Dark-gray. Fresh. Minor vesicles to 265 ft. Minor clay (caved?). l
/*a . , ~
210- -260 . , ,, *, ., ' * , Tem 7 *, . .. u ...,i u T ,* ,.' *l, i 200- -270
, y, , *,.' .-
- BASALT. Dark-gray. Fresh.
. Nonvesicular. Local pyrite or calcite
{ . , ,' *, *,*, mineralization on some surfaces. Minor vesicles from 270 to 280 ft.
' f f , *. and from 290 to 300 ft.
~_ ...,
s ,',*** 190- -280 , *,; 1,* * *
~ ~ . .-.;.
S.'3,*....
....'s'
_- s ...< m .
- ' f. .,,
I.*,"*.*.' 180-- 290 .'.*,..' g :::.'
- x. . .b .. e*9 170-- 300 '.-., ..." ". .
c ...e. ,.. . __ ,e,.**,' g 3 9
,. s PUGET SOUND POWER & LIGHT COMPANY FIGURE LOG Ci: DRILL HOLE MJ-2 i"$
SKAGliI HANFORD NUCLEAR PROJECT .' $
- 2R-A-113 AMENDMENT 28
, -- . m.m_e.: ; , p .n - ~ . z.s.
.;.~ . ;- .-- ..
p' = . > ,, c. a
- L i ?; ~. L W. R W'i+1 :" I,w ? t
- 1.e..+ 5~ ,%r :% 7 . ";V ;'. .. y'.~'. >.* ,
%,y: .. ,'_ .
"- I. L !. :
. !. . a. '.
10/15/82 I DRILL HOLE m-2 Page 1 of 6._ f *** Dgth ( , #* go Lithologic Description Unit 5 ', ",.
* , ' BASALT. Dark-gray. Fresh. Nonvesicular. Local calcite or pyrite on
,* ',,,,. , y*,'1 some surfaces from 320 to 330 ft.
160-- 310 , m* a # 6 P 2,4.,6 3,. . Tec
..a.,.
a 150-- 320 ,. ,.'.
,. ,,./
S _- , " , '[ *.'. r .*.,,
; <s,e
'a* I .* l ' BASALT. Dark-gray. Vesicular. Vesicularity increases with depth.
140--330 . '.,, ,' l .*, Vesicles at 335 to 340 filled with green clay. 2 , .. . :: ____---__-_______
*.,a.
.a.,.
A . .6 . l. . 130--340 m,g NM P. Clayey SILT to silty CI.AY. Light-olive-gray.
-- :t. %m Eb.'.13b dt1;t 120--350 R ;;
r i -
, {l'l' g
l AJ SILT to clayey SILT. Grayish-yellow-green. Tuffaceous.
-- j a 5 d il
.' t . 1 p Ter 110- -360 l
M' - , Clayey SILT, with CLAY and tuf f aceous f ragments. Pale olive.
-- h
)v$,
100-- 370 m gih
-U.,
-~ 5 k ip S hr h'l 90- -380 {,l1i ,
@ \
L <* , . : (
-- l'ik 10 o. i ,h
.,y , , . a PUGET SOUND POWER & LIGHT COMPANY LOG OF DRILL HOLE MJ-2 M FIGURE SKAGIT / HANFORD NUCLEAR PROJECT 2R-A-113 AMENDMENT 28
10/15/82 DRILL HOLE va-2 Pag..ci_.or s._
** th Uthologic Description g .
- go Unit
- g. .
{ g i I Clayey SILT. as above. Pale-olive to grayish-olive. Vesicular i basalt clasts in sample at 395 to 400 f t. 80--390 _ l fl Il Ter 3 'l y g [0i] TY. l 70- - 400 l ;,; ,';;
^'
-- ::.~::;*'*
- . , , , * ' BASALT. Dark-gray. Moderately fresh. Vesicular. Some vesicles 1, , . , ' . , filled with green clay. Caved material from Rattlesnake Ridge
...** interbed from 405 to 420 ft. Basalt extremely vesicular from 415 60- - 410 .
.'t*'.'< to 420 ft.
Tp r* ;, .. . _- . f : *. s ., ., ,., ,. ,. ' . 50--420 .* *.. ** '/. 7 s... ...,,
,e9..
46.2-- E0H 425' _o VW PUGET SOUND POWER & UGHT COMPANY FIGURE SKAGIT l HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-2 2R-A-113 AMENDMENT 28
i I 10/15/82 , DRILL HOLE S-3 1 SAMPLE TYPE Page .L of _3_ . Projtet No : 823-1036 l
@ Cuttings j Elevation : 468.5 ft.
95 Core, Number Indicates % Core Recovery '
*' h8.18;E262.629.38 b451 C2015 8 XRF, With Sample Number Coorhes :
Date Completed : 8/26/82 Chemical Results Listed in Tabis 2R-1 Unit Column Refers to General Stratigraphic Divisions identified Within the Site Area : M - Missoula 111 - Ringold, Cycle ill B - Basalt, Undifferentiated PM - Pre-Missoula 11 - Ringold, Cycle 11 EV - Elephant Mountain Member RR - Rattlesnake Ridge Interbed IV - Ringold, Cycle IV 1 - Ringold. Cycle 1 P - Pomona Member Elevation Depth c@ e\ k0 Lithologic Description Unit (ft.usL) (feet) ogS9
$ 1 Silty sandy CRAVEL to gravelly silty SAND. 50 to 55% basalt clasts. Sand
_ 5'.- ) ( yellowish-gray; very-fine-grained; angular to subangular. e;h e1 *..',- 6 Gravelly SAND. 75% basalt grains. Very-coarse-grained. Angular to 8 angd ar. 460-
.. s e .
-10
'gj.yy M m
a W@.1-9
,V
[4*y
. .c.
Silty sandy CRAVH. to gravelly silty SAND. 50 to 75% basalt clasts. Sand poorly sorted; very-fine- to very-coarse-grained; 45 to 60% basalt
} g:y .y grains; angular to subangular.
450 - "9eE
-20 j$ .
5 iE![' [fd:J@ E q .. .- e, .
-,l N ,'
w f. 440 - Gravelly silty SAND. Yellowish-gray to dusky yellow. Ve ry-fine-
- 30 % .s f grained . < 1% mafics. Angular to subangular. Gravel <45% basalt o fM. clasts.
- 3. 3;.f n.
- -a M.g 430- tY
- Silty sandy GRAVEL to gravelly silty SAND. 20-25% basalt clasts.
- 40 y No cement rinda. Sand moderately to poorly sorted; 5-7% mafics; PM
, subangular to subrounded ; yellowish-gray to dusky yellow.
+
i $ *-
,- pg$' .
I 4: ja
- W
*: Gravelly silty SAND. Yellowish-gray to dusky yellow. 7-10% mafics.
~ *
{j' f ' Very-fine to medium. grained. Angular to subrounded. Gravel 25% 420 - ~, yy j- ' basalt clasts; no cement rinds.
- 50 h..;.. 1-
~
](? g Silty sandy CRAVEL. <50% basalt clasts. No cement rinds Matrix q.7,jy -g light-olive-gray to moderate-olive-brown. Clay at 55 to 60 ft;
, t,. . , ..f g possibly weathered basalt clay. /
\
'Qf .
410 -
-e0 - l, 5
- BASALT. Oive-gray. Weatheted. Nonvesicular. T
_ y.*J 7 T. \ p a pv
# %qw.*
PUGET SOUND POWER & LIGHT COMPANY FlWRE SKAGIT / HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-3 \j>- 2R-A-114 ' 1 AMENDMENT 28
10/15/82 DRILL HOLE S-3 Page l_of.i._ U m "*" oepth u..i- eg,# utholo9 e o**cription unit usL) (feet) g*9 400-3 */,*...2[-. .BASALT. Olive-gray. Weathered. Silt and clay at 70 to 75 ft.
- 70 ' . * , ' . * . ,<
<s v.,,
2 o.*.e '* ss< = l 4,
" . l ',
= . ...
D *
$ . ' * , ' BASALT. Medium-dark-gray at 75 to 80 ft. Dark-gray from 80 to 135 ft.
390- '**.
. . " Fresh vesicular to 135 ft. Some vesicles filled with yellowish-green or
- 80 **,8,' white clay.
e.,*., e, 1 , . ,, * * . .,.
....,a,<
{ '* 380- , . /.' ,*;
- 90 ' , ,,*,
x ,.,',*' x . *:
- *
- f.
*a '
- T'..*. .l ,l **
370- ,,. .
-100 '
- ,. , . . '
- Tem h ,**,e*' , , ,,
7 , * < * . m . . ., 360- ****
-110 *. ,
l
.,a.'
d
~
"T'
,
- 9 .f .6 .
x ..'*. 350- ,'t . . .
-120 '. .*. .t 2, ,*
> .A
[ i i l y
\' . . 4 1 340- l,****
l - 130 . I * ** * ' l t - 2
.,.,.a a
- e. ,'
&.9 ,
,e.n.a,. .
r.:.... 330- '..'.*l.
-140 **'**-
.'.',e'.
- BASALT. Dark-gray. Fresh. Nonvesicular. Calcite on f racture surf ace at 140 to 145 ft. ,
3 " * . . .* , (.
^
_ '..*,t... t , c.
..% .x PUGET SOUND POWER & LIGHT COMPANY FIGURE LOG OF DRILL HOLE MJ-3 SKAGIT I HANFORD NUCLEAR PROJECT 2R-A-114 AMENDitENT 28
10/15/82 DRILL HOLE C-3 Page.1_ of s.,_
- D.pth *\ Lithologic De.cription
,,ga u..a + ef Unit g ,,'a,*.' BASALT. Dark-gray. Fresh. Nonvesicular. Calcite on fracture surface 320- . *! *. '. at 170 to 175 ft.
-150 .' , ' . ,
,, .
- J -
&!*s'
,.a.
. . *f. . *','
c . . . t ', 310- y ','. ,' l ,
- 160 .'.**.
. * **. Tem I ,.;.,1., *.,, <
."4 ;; ;',
3 $!',*.! 000- .**.
-170 ..l.*,'..'<
s .... ' E'**4'..
" '
- BASALT. Medium- dark-gray from 175 to 185 ft. Fresh. Minor vesicules 290- " , *,.,', at 180 to 185 ft.
-180 */ ..l ** s* .-
a m..',: *..'. - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ p n.n.
$ t 280-Eg!~r g Clayey SILT to silty CLAY. Light-olive-gray. Caved vesicular basalt
. . - clasts.
-190 7
[ *D w_ :-
]f C.'ayey SILT. Light-olive-gray. Tuffaceous.
270-
-200 hl h* M l ;
{***,y - Clayey SILT to silty CLAY. Light-olive-gray. Tuffaceous. Ter hY.- m aL 7 E u * * - ' . Silty CLAY to clayey SILT. Grayish-yellow-gretn. Tuffaceous. 260- .3
^' ~
-210 y M
"" Sandy clayey SILT to sandy silty CLAY. Crayish-yellow-green.
Tuffaceous. i
*.e.
, Sandy silty CLAY to sandy clayey SILT. Grayish-yellow-green.
Tuffaceous. 2W
-220.
- h., Sandy clayey SILT. Crayish-yellow-green. Tuffaceous. Sand very-fine-2 ; M grained.
~ .
hk.h PUGET SOUND POWER & UGHT COMPANY xJ mURE SKAGIT I HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-3 2R-A-114 AMENDMENT 28
10/15/82 DRILL HOLE MJ-3' Page.4.L., of h._, [" Depth o\
,# Uthologic Description Unit .o u..o **
N Sandy clayey SILT. as above. Ter S ,-[4' i .I { I 240 - 4i ' {'!.- - - - - - - - - - - - - - - - - - - - - - - 1
- 230 ,
zx .=.,a..
.- c . ,,
, ,' /,. : 2
. * ' , *. BASALT. Medium-gray grading downward to medium-dark-gray. Moderately 2 .:,'*..* ' ' fresh. Vesicular. Some vesicles filled with green or white clay.
230- ' ' , . , . .'
- 240 a,',*.*
- d 0,,.'..
., a Oc><,,<*
220- ,.',',',.
-250 .e',',**
BASALT. Dark-gray from 245 to 260 ft. fresh. Vesicles decreasing. 7 ,. * * ,> Calcite crystals at 250 to 255 ft. O*,*,**.'.' Tp
' . ..P. .
- 1. , = , *, * . l 210- * , . '
- 260 ,',e'."',
s ;.,... .'. _ .*' , ' , , , BASALT. Crayish-black from 260 to 270 ft. Fresh. Large vesicles at
*. 265 to 270 ft. Increase in size of plagioclase phenocrysts at 260 to T ':
J > ,,, ' 265 ft. 200 - ***..,
- 270 ,
195.5-E0H 273'
#' b
$ . ' 'b s
,.v ,
(i* v PUGET SOUND POWER & LIGHT COMPANY FIGURE SKAGIT I HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-3 2R-A-114 AMENDMENT 28 s ,
w No"'ll OUQA;DMb fisuIsa.s 42 A to A A - B - /0 A aR - B .v/ 2A-13 2.4A
.14-6 36
.22 36 A
.2 4 5.L and .24 S.2. /9 1
i _. . _ _,._ _ __
~ ~ ~ ~- - - - - - -
S/ENP-PSAR 10/14/82 QUESTION 231.5 (Regulatory Staff Position): Additional investigations may be required of the Appli-cant to confirm the presence or absence of potentially hazardous geologic structure which may have been identi-fled.through existing data utilized in the response to RAI 231.4 but which lacks sufficient resolution for determination of capability or noncapability.
RESPONSE
Subsequent to the Applicant's response to RAI 231.4 and a meeting with the NRC staff on July 8 and 9, 1982, the staff determined that some additional investigations were required in one area for which there was not, in their judgment, sufficient information to confirm the presence or absence of hazardous geologic structure. Their request for additional information was forwarded to the Applicant in the form of Question 231.14. The Appli-cant's response to this request for additional informa-tion is provided in Amendment 28 to the PSAR. Q231.5-1 Amendment 28 I I
l S/HNP-PSAR 10/14/82 QUESTION 231.14. The' Applicant will conduct a core boring program of sufficient scope to determine if the May Junction' mono-cline is fault controlled. If fault controlled, this program should provide sufficient new subsurface evidence demonstrating-that the fault is not capable. This may include other subsurface techniques and information to supplement the core borings. This program should be of sufficient scope to define the attitude, sense of move-ment and age of last. movement of the fault and be designed to carefully recover and define the overlying i formations in this area. RFSPONSE: In response to this question, the Applicant undertook a l program of exploration using gravity measurements and rotary-wash borings. This program developed sufficient evidence to demonstrate that the May Junction monocline , is not fault controlled. ' Thus, core borings were not required. $Y Definition of May Junction Monocline The May Junction monocline is defined by the 2000-foot wide, north-south gravity gradient extending 2.5 miles through sections 28, 29, 32 and 33 of T13N, R27E, and sections 4 and 5 of T12N, R27E (S/HNP PSAR, Appendix 2K, Figure 2K-15). It was first recognized on the basis of aeromagnetic data (Myers and Price, 1979) and termed the May Junction linear (Magnteic Features Map, RHO-BWI-ST-4, Plate 111-6d). Investigations for the S/HNP PSAR, ' including gravity surveys and drilling, showed that the aeromagnetic linear was produced by a gentle easterly slope on the buried bedrock surface. On the basis of this bedrock structure, indicated both by gravity surveys and drilling, the feature was interpreted te, be a gentle monoclinal fold and termed the May Junction monocline. Exploratory Program In a meeting with the NRC staff and representatives of the USGS on July 21, 1982, a-program of investigations to , address Question 231.14 was proposed by Applicant. The program contemplated three steps. First, a gravity l survey would be performed to characterize the May Junc-i tion monocline in greater detail so that locations for b q rotary-wash' borings could be selected. Next, rotary-wash Q231.14-1
@(
Amendment 28 i: - ~-
S/HNP-PSAR 10/14/82
.QUESTION'231.14 (Cont'd). , borings.would be drilled to evaluate the bed rock struc-ture. 'And, finally, core borings would be drilled to determine the' characteristics of any faults that might be discovered._ NRC staff agreed that the program was responsive to'their: request for additional information
_-(NRC' Letter, Novak-to Myers dated August 4, 1982) and the c program was implemented. New gravity stations'were established in sections 32 and , 33 of T13N, R27E, approximately 1 mile south of Gable Mountain (Figure 231.14-1), along nine new traverse lines
'(8A-8H, 8J) and portions of Lines 8 and D at 100-foot ,
station' intervals. All-gravity stations were surveyed ( , and both vertical and horizontal control provided to the i nearest 0.1 foot. The newly acquired data were evaluated ( in profile. They were also combined with the NESCO data ( , set (S/HNP PSAR, Appendix 2K) to produce a total Bouguer ! 3 gravity anomaly map (Figure 231.14-2). The gravity ! anomaly contours on the May Junction monocline are consis- i tent with'.a north-south trending bedrock surface sloping i
-gently and uniformly downward toward the east.
l
-Line 8C was chosen _as a drilling location because of the il typical character of the gravity profile-(Figure Ih 231.14-3) and the anticipation of a thick section of !
Ringold.' Three rotary-wash boring locations, spaced equi- f distantly across the steepest part-of the gravity j anomaly,-were selected and discussed with the NRC and i USGS staff. { '
.The rotary method of drilling was used because the most
}
-important contacts in the section for determining the i bedrock structure _are the basalt / sediment contacts, which [
are easily recognized from data generated by this drill- ) ing technique. The elevations'of these contacts were j determined from detailed examination of the lithologic j characteristics of the drill cuttings (Figures' 231.14-4A, B and C) combined with interpretation of four down-hole < geophysical logs for each hole (Figures 231.14-5A, B, C ' f and D). -The elevations'of these contacts, particularly the Ringold Formation / Elephant Mountain member contact, { the--Elephant Mountain member / Rattlesnake Ridge interbed contact and'the Rattlesnake Ridge interbed/Pomona member contact, were used to determine the thickness and dip of the various units along the line of section. Table 231.14-1 shows the-thickness of the several' units encoun-m te' red in the-three holes. Figure 231.14-6'shows the # [ correlation' bet' ween stratigraphic units recognized in borehole.MJ-1 on Line 8C and holec' drilled on Line 8 to i h g 3 I .. X Q231'.14-2 -Amendment 28 _,m% , (
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S/HNP-PSAR 10/14/82 QUESTION 231.14 (Cont'd) the north and Line 3 to the south, thus demonstrating the continuity of stratigraphic units along the strike of the monocline. Figure 231.14-7 shows the geologic cross section across the monocline at Line 8C. Results: ! I The above investiqation has shown the f ollowing: (l
- 1. Gravity anomaly and top-of-basalt contours are f consistent with those drawn from earlier data and '
portray a gentle (70-100) continuous slope without i abrupt irregularity.
- 2. Borehole intercepts of the top-of-basalt lie along ,
a nearly straight line. l l t
<! 3. The Elephant Mountain basalt / Rattlesnake inter-f ~i bed /Pomona basalt contacts are nearly parallel and define unit thicknesses that vary slightly but [
which are well within the range of normal thick- } ness f or these units throughout the Hanf ord Reservation. 3
- 4. The entire Ringold section is present in the most If
)
downslope boring (MJ-1) and correlates well with ! other borings along strike. [ Interpretation of Results
}
There are four lines of evidence which indicate that the i J May Junction monocline is not f ault controlled. These are: [ e o the smooth surface of the basalt as defined by 'l drilling and gravity (Figure 231.14-7 and -8), :I o the shallow (70 to 100) dip of the stratigraphic 1 units which form the monocline, I o the unif orm dip (+30) of the stratigraphic units between the dril1~ holes and , I o the generally unif orm and typical thicknesses of L -
~
the Elephant Mountain member encountered along the p . line of section. < l The shallow dip of the units across the strike of the monocline has been recognized from previous geologic and # [a i g 0231.14-3 Amendment 28
S/HNP-PSAR 10/14/82 QUESTION 231.14 (Cont'd) geophysical studies (S/HNP PSAR, Appendices 2R and 2K). Results of the present investigation have confirmed this observation and have specifically shown that the units do, in fact, have a shallow dip (70 to 100) along Line 8C (Figure. 231.14-2). The units for which this shallow dip has been confirmed along Line 8C include Ringold Unit I, Elephant Mountain member, Rattlesnake Ridge interbed and the Pomona member. The shallow dip of.these units indi-cates that, although the monocline is a prominent-geophysical feature, only minor deformation has taken place in the basalt or overlying sediments along the trend of the monocline. This minor deformation has clearly been accommodated by the warping which produced the monocline. i In addition to the very gentle dip of the sediments and i basalt units across the monocline, the fact that the dip ; of the units remains nearly constant between the drill l holes indicates an absence of fault control. If the feature were fault controlled, and some offset of the basalt and overlying sedimentary units had occurred, such l an offset would be reflected by variations in dip across the feature. Since there are no significant (>50) variations in dip and contacts across the feature lie along nearly straight line projections, there can be no dh significant fault offset between the drill holes. There is certainly no offset of the type that might be asso-ciated with a fault presumed to have caused nearly 300 feet of relief on the bedrock surface over a distance of only 2.5 miles. Table 231.14-1 shows the elevations of contacts and thicknesses of units encountered in the three rotary holes. The Elephant Mountain member, in particular, is shown to have a very uniform thickness along the line of section. Some thickening is observed in MJ-2 in the Rattlesnake Ridge interbed; however, it is well within < l the normal range of variability in thickness of this unit j observed elsewhere in the Pasco Basin where faults are known to be absent. None of the units show changes in thickness which could be interpreted to result from thinning or thickening due to displacement on a fault. Upon completion of the rotary drilling program, a model ' of the subsurface geology that satisfies both the results of drilling and the gravity along Line 8C was constructed ( (Figure 231.14-8). The densities used for the units are jf 2.60, g/cm3 for the basalt, 2.45 g/cm3 for the Ringold (p l Basal Unit I gravel, and 2.0 g/cm3 for the Rattlesnake g% Q231.14-4 Amendment 28
l S/HNP-PSAR 10/14/82 QUESTION 231.14 (Cont'd) i Ridge interbed and the remainder of the sedimentary ! section. The modelled basalt surface varies smoothly. i, The change of Bouguer gravity anomaly across the May
- Junction monocline is due to the change of elevation of the top of basalt, change of density in the Ringold f section and variation of the regional Bouguer gravity :
anomaly. The change in elevation of top of basalt s accounts for at least 90% of the change. No evidence for + offset is present. ( , Conclusions t Based upon all the available data, the following conclu- i sions are-drawn:
- l. The May Junction monocline is a broad, gently-sloping fold in the basalt /interbed sequence; pf
- 2. No evidence of irregularities in the basalt surface or in subjacent or suprajacent units has been found to suggest fault offset;
- 3. Cumulative evidence indicates an absence of I evidence for faulting or " fault control."
}
Based on these investigations and the'other data avail- . able, investigations on the May Junction monocline have been adequate to provide reasonable assurance that the feature is not fault centrolled. No further investiga-tive work is needed to confirm this conclusion.
~A
(\ p Q231.14-5 Amendment 28
TABLE 231.14-1 Sheet 1 of 2 F ELEVATIONS OF CONTACTS AND THICKNESSES OF UNITS _ ENCOUNTERED IN DRILLHOLES ALONG LINE 8C = MJ-3 MJ-2 MJ-l Top IV Depth NP N? 124 Elevation NP NP 352 i Thickness IV 0 0 82 E Top III I Depth NP NP 206 ' Elevation NP NP 270 Thickness III O O 36 Top II Depth NP 85 242 4 Elevation NP 385 234 I E Thickness II O 95 66 { I QY
- Top I-u y '.
2 Depth NP 180 308 Elevation NP 290 168 l 2 Thickness I-u 0 10 33.5 ? 's 2 j Top I-b I 4 l d Depth NP 190 341.5 3 w Elevation NP 280 135 i T Thickness I-b 0 14.5 39.5 i P . y Top Tem Depth 55 204.5 381 5 Elevation 413.5 266 95 > Thickness Tem 127.5 127 113.5 . Top Ter j -= Depth 182.5 331.5 494.5 Elevation 286 139 -18 : Thickness Ter 46 65.5 35 l - - \ 5 kq.,s
n i l
/ l TABLE 231.14-1 Sheet 2 of 2 :
MJ-3 MJ-2 MJ-l Top Tp i Depth 228.5 397 529.5 Elevation 240 73 -53 Thickness Tp - - - l I e i NP = Not Present I-b = Ringold Basal Unit I I IV = Ringold Unit IV Tem = Elephant Mountain Member f III = Ringold Unit III Ter = Rattlesnake Ridge Interbed ; II = Ringold Unit II Tp = Pomona Member l I-u = Ringold Upper-Unit I t i I i i 4 l' 6 P ~
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DRILL HOLE MJ-2 SAMPLE TYPE Page _1 of __6_ Project No : 823-1036 88 Elevation : 476.3 ft. 95 Core, Number indicates % Core Recovery Total Depth : 573 n ft. Coordinates : m 1.*co.11, r?st sit m C2015 XRF. With Sample Number Date Completed : _ 9/15/82 Chemical Results Listed in Table 2R-1 Unit Column Refers to General Stratigraphic Divisions identified Within the Site Area : M - Missoula Ill - Ringold. Cycle ill B - Basaft, Undifferentiated PM - Pre-Missoula 11 - Ringold. Cycle il [ f,'ttP "' sna e Rid e n bed IV - Ringold, Cycle IV I - Ringold. Cycle 1 P - Pomona Member Elevation Depth cd*fd t00 Lithologic Description Unit (f t.MSL) (feet) gS9 8} 8
, Gravelly silty SAND. Light-olive-brown. Medium- to very-coarse-grained.
1 p I t, l.
.e 470 - e .. A C Crave 11y silty SAND. Olive-gray. Very-fine- to very-coarse grained.
,']
_. ' y fining with depth. 60 to 75% basalt grains. Angular to subrounded.
- 10 '
s e
...:Q r .
460- -
- 8f [*8 ,.
g 'e
~ 20 g d ::~
Crave 11y silty SAND. Medium-dark-gray grading to medium-gray at 30 to e' 35 ft. 55 to 80% basalt grains, decreawing with depth. Very-fine- to
; . very-coarse-grained. Angolar to subrounded. Cravel 75% basalt clasts.
-e j
450 - , 1 f' P d
.e C
~ 30 lel
.i l a
,40-
,g p ,p.
_ Silty CRAVEL to gravelly S1LT. Light-olive-gray. Ferruginous stain.
, j,j, q Cravel basaltic; possibly caved.
~
- 40 M y $ Crave 11y SILT to silty CRAVEL light-olive-gray.
N
- 430 -
2 t {l Crave 11y sandy SILT to silty sandy CRAVEL. Light-olive-gray. Spotty ferruginous stain. Sand very-fine- and medium- to coarse-grained.
- 50 - PM g
.m{ . .,h.-
.r . .;.
Silty sandy CRAVEL. 30 to 50% basalt clasts, decreasing with depth. Sand very-fine- to very-coarse-grained; mostly coarse- to very-coarse 420 - }-
- E ' ***
- 8#* "
a ;f,'d,. .
- 60 n.
- p. t .
~
e. 7 .'y;. Gravelly SAND. Yellowish-gray. Fine- to medium grained. 10% mafics.
) d' Angular to subangular. Trace silt.
_l k _u r' PUGET SOUND POWER & LIGHT COMPANY FIGURE SKAGIT / HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-1 as 1.t a-a A
DRILL HOLE m-1 Pagel_ of .1_
'oo
.7o u..o Depth s e ge k Lithologic Description Unit 410- g f.y -].'. Sandy CRAVEL. 20% basalt clasts. Sand fine- to coarse-grained; 10 to 15%
*, 0. * *" *- mafics; angular. Trace silt.
- 70 -
- js* Crave 11y silty SAND. Yellowish-gray to light-clive gray. 20 to 25%
1 o mafics. Very-fine- to coarse-grained. Angular to subangular. 1
~ W.y7 400- . *.j{.{k Crave 11y SAND to sandy CRAVEL. Yellowish-gray to light-clive-gray. Fine- l
. ., to very-coarse-grained; mostly very-coarse-grained. 30% basalt grains.
~*
- f. d) k -
2 i Crave 11y silty SAND. Yellowish-gray to light-olive-gray. Very-fine- to very-coarse-grained. Crain size decreases and sortinc is poorer with dept! .
;*e .j { 25 to 30% basalt grains. Silt increases with depth.
390- r . N
^el
- 90 p\ .n 1
~
Silty sandy CRAVEL to gravelly silty SAND. 45% basalt clasts. Sand as FM above. 380- a *l 5 ? Gravelly silty SAND. Yellowish-gray to light-olive-gray. Very-fine- to a9 medium-grained; mostly medium-grained. 15 to 20% mafics. Local ferru-
-100 .*a'! c ginous stain.
~
.f.'...'
7'
. M.'8
- Silty sandy CRAVEL. Matrix as above. Local ferruginous stain. No sandy
'. ' . , cement rinds.
370- - rw[-tr
/, ,*,$/, Gravelly silty SAND to silty sandy CRAVEL. Yellowish-gray. Ve ry-fine -
u , , , . . . ,,, ' to coarse-grained. 10 to 15% mafics. No sandy cement rinds.
-110 eg*
d.-* s '.' Crave 11y SAND to sandy CRAVEL. Yellowish-gray. Fine- to medium-grained.
***. *[ ,* ] 7 to 10% mafics. Angular to subangular. Clean. Gravel 15% basalt
*e s clasts; no sandy cement rinds.
360- r- .g'.{, ,
%.. . ,.g.' . .* .*
- 120 Q ,;
,. !$F: Sandy CRAVEL to gravelly SAND. Sand as above. Some pebbles with yellow Q QD h sandy cement rinds (reworked Ringold?).
- 9.Z
- 7. g i.';c..
z%.------_----___---___ 350- j*.QW
- k. .tl2.Yt.
-130 0 4*..
E *' ~ Gravelly SAND. Yellowish-gray to dusky yellow. Fine- to medium-grained;
' , ' c.il a mostly medium-graine3. 7-10% mafics. Angular to subangular. Abundant gravel clasts with yellow sandy cement rinds. IV 340- y E '.*,hy q
-140 0 4.fa .
*g, 7
,2s3 g
~
M AL
#%W PUGET SOUND POWER & LIGHT COMPANY FIGURE SKAGIT / H ANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-1 g33.,4 44
DRILL HOLE m-1 Page_i_ of _E 3
- pth id o ge Uthologic Description Unit 330- ll{* ,
w.~ t. e. j; * *. Silty sandy CRAVEL. Matrix yellowish-gray to dusky yellow. Sand fine- to
-150 ,., ;$,1,'; medium-grained; mostly medium-grained; 5 to 7% mafics; angular to sub-2
-*
- 33- .q . , angular. Yellow sandy cement rinds on gravel clasts.
'/J '
M.iE 320- , ...,, 1 e, _1* ' Gravelly SAND. Yellowish-gray grading downward to dusky yellow. Very-
-160 *
- . , ~ . . fine- to medium-grained; mostly medium-grained. 5 to 7% mafics. Angular r o' to subangular. Abundant yellow sandy cement rinds.
,ce,,
.fe-310 - <
- f. l Silty SAND. Yellowish-gray to dusky yellow. Very-fine to mediun-grained; 1 e mostly fine- to medium-grained. 5 to 7% mafics. Trace gravel. yy
- 170 w b' I,N Silty SAND to sandy SILT. Dusky yellow. Very-fine-grained.
d di: 1j 4'0 300- - i
-180
- r 3
. ll SAND. Yellowish-gray. Fine- to medium-grained; mostly medium-grained.
, 7 to 10% mafics. Angular to subangular. Trace silt from 180 to 190 f t.
290- y yg... Micaceous at 185 to 190 ft. and 195 to 200 ft. Trace gravel with yellow a sandy cement rind at 195 to 200 ft.
-190 s
., o L '
. t 280- [ ,
- 200 -
1 hh
,l.5M Sandy CRAVEL to gravelly SAND. Yellowish-gray to dusky yellow. Abundant yellow sandy cement rinds.
. VY
- . .- s' 3.
27b =
. e. . . Gravelly SAND. Dusky yellow. Local ferruginous stain and cement.
8 ' f .*
- 210 h- 2--- -
1 ' e..
.e Crave 11y SAND. Light-olive-gray. Fine- to medium-grained; mostly medium-grained. 15 to 20% mafics. Wood f ragment s. Micaceous. Sandy g.* A cement rinds.
- A 260- 7 SAND. Light-olive-gray. Very-fine- to medium-grained; mostly medium-grained. 20% mafics. Micaceous.
m
-220 y.
{' * . . ** , . *, CRAVEL. Trace sand. 15 to 20% basalt clasts. Trace sandy cement rinds.
- a. .*. ;
- k
.P M J' PUC ( SOUND POWER & LIGHT COMPANY RWRE SKAGIT / HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-1 es t.t a.u
DRILL HOLE MJ-2 Pa ge_i_ of .8 U' * " g Depth g,# e c Litholo9c i Description Unit 250 - 6 **-
; ** .* CRAVEL as above. Pyrite on some clasts.
- 230 M
- Sandy CRAVEL. 35% basalt clasts. Local pyrite. Minor yellow sandy
, . l. 2.*.
- g 1 /.*,**.', ' *
- cement rinds. Sand matrix fine- to medium-grained.
240 - Gravelly sandy SILT. with CLAY and ash-like fragments. Very-light-gray.
] @ pM olive-gray, and light-olive-gray. Gravel and sand prooably caved.
i 17 Pyrite fragments. Some silt and clay fragments laminated. idi
- w.-.
MU # 230- p. . ' Crave 11y silty SA2. with CLAY f ragments. Light-olive-gray. Very-fine-
; :g-- to medium-grained.
-250 'T:va'j -
g. y ts '-
- p. n.. .
220 - SAND. with clay and white ash-like fragments. Yellowish-gray. Very-fine
*~(
E to fine-grained. Mostly fine-grained. 5 to 7% mafics. Trace gravel.
- .e r
-260
- e.1 -s }e A e yl -{ {Gravelly p ' silty SAND with SILT fragments. Yellowish-gray. Very-fine- to medium-grained. 10*. na fic s . Angular to subangular.
' ig{".
210- 6 ,,
- 'l-s ]E.j
-270
_ Md Crave 11y sandy SILT to CLAY. Yel'owish-gray. Slight waxy luster to clay. 156= E Q 11 200- { Gravelly sandy SILT to gravelly silty SAND. Yellowish-gray. Sand very-fine-grained.
-280
}*h I Crave 11y silty SAND. Yellowish-gray. Very-fine- to fine-grained; mostly very-fine-grained. 3% mafics. Angular to subangular.
} (.<e
.e:: ,.t*
3 190 - l ~f - ! Silty SAND. with CLAY fragments. Dark yellowish-brown. Sand as above. j.g.p-
- 290
,, .1.
..j:f
* ~
p; Silty SAND. with silty SAND to sandy SILT fragments. Yellowish-gray. _ . ; -f Very-fine- to medium-grained. 2 to 3% mafics. 3._ 180- _ ff 5 ((t;.)
-300
{
%*cU.; Crave 11y silty SAND. with CLAY fragments. Sand yellowish-gray.
Clay dark-yellowish-brown. Very-fice- to medium-grained. > m #h W GW PUGET SOUND POWER & LIGHT COMPAN) V FIGURE LOG OF DRILL HOLE MJ-1 SKAGIT I HANFORD NUCLEAR PROJECT 2 3 3.s a-a a
DRILL HOLE C-1 Pa ge.L. of .fL. g . ' " D th
- sc Lithologic Description Unit 170 -
1, $ f- Gravelly SAND with dark yellowish-brown CLAY f ragments. Yellowish-gray.
- 4. . }. . , Fine- to coarse-grained;mostly medium-grained. 3% mafics. __
- e. e
- 310 7 Q,$*J I
- +- s
- Crave 11y silty SAND with silty clayey sand fragments. Light-clive-gray. '
[- Very-fine- to medium-grained; mostly fine-grained. 2 to 3% mafics. 180 - 3 Pf Angular to subangular.
~
x .:.nyg y' 3:
- 320 pQ
, , , , h, ;
1 j. 3 Sandy clayey SILT. Olive-gray. dd
- - e- 1-u
{ ', .{ Crave 11y clayey SAND. Olive-gray. Medium- to coarse-grained.
- . 5.
's 2
- 330 g,e.-e'. ,
Crave 11y silty SAND. with SILT and CLAY f ragments. Light-olive-gray. 9 .e. Very-fine- to coarse-grained. 3% mafics. Local ferruginous stain. e a TL?L 140 - , I? J Crave 11y EAND. with SILT fragments. Light-olive-gray. Fine- to medium-1 l.,.*]{i , .. *;1, grained; mostly medium-grained. 5% mafics. Local ferruginous stain.
- 340 >
SAND. Light-olive-gray. Medium-grained. 5 to 7% mfaics. Micaceous. Tal; , Trace gravel. 130 - "
;* .l * < l o ...*.*'
.f *l*,.*4 Sandy CRAVEL. 20% basalt clasts increasing downward to 40 to 45% basalt
- 350 ..j;
. *f- clasts. Some sandy cement rinds. Blue cast to some basalt clasts. Local
_ * ;*f
- ferruginous stain and cement.
c N '9.. .:.~.~.
.it:.-
g.. t' i 120 -
- v q(.
4..
-340 *****
^
* ' ' ' . =
- CRAVEL. Trace sand. 30 to 40% basalt clasts. Sandy cement rinds.
*'**I.'<
. . . Blue cast to some basalt clasts. 1-b 110 - '*
., .l.'.*.*-..
.". ; **, l
- 370 .*.
S. . , . . . . . 100 -
~
Y j*g.h*f Silty sandy CRAVEL. 30 to 40% basalt clasts. Sand very-fine- to medium-y W grained; yellowish-gray. t.-),f.f
...g , , -
- 380 M.:
3 . ..
.*e ll*l.*/ Basalt. Dark-gray. Caved gravel clasts. em Y M RE PUGET SOUND POWER & LIGHT COMPANY LOG OF DRILL HOLE MJ-1 SKAGIT l HANFORD NUCLEAR PROJECT est.14-4A l l
l
l l 1 1 DRILL HOLE m-1 Page_JL of _fL. y';*(*" (Depth e\ ithologic DeQription Unit ust) feet) M gt*
** 1 90 - i
- 390 S,
',,.a.;
f ., ., BASALT, as above. Some vesicles. s : .,. , . a ..
., * BASALT. Dark-gray. Weathered. Vesicular. Some vesicles filled with 80- ; i...*< '
. * * , ., green and white clay.
- 400 .. ,
x 70- a .... 2 . ,<, * , ., . . " .<
-410 **.;
BAFALT. Dark-gray. Vesicular. Moderately fresh. Some caved gravel.
, ...l..
r, . " . . * . eO- - /,. /.~. ; M. .s, . ..
-420 '.i ,*.a.
.d ..j BASALT sand. Crayish black. Fresh. Ground to sand size by drill bit. Tem
- v. . , .
..i*
50- m a *, . ',* l. a '
'* , / .'
*** BASALT. Brownish-gray to grayish black. Fresh. Trace vesicles. Local
- 430 . ; * .,.
_ ,,l g,. ,* , , pyrite mineralization at 430 to 435 ft.
*...s. ..
40- m ' . * * * . BASALT. Dark-gray to grayish black. Fresh. Nonvesicular.
-440 , / I *'
. BASALT. Olive-gray to olive-black. Vesicular. Some vesicles filled with
'[.*.*** ' , .green '
- clay. Some brecciated clay fragments.
30- 5 * ,'-I,*.,
,,f.** , BASALT. Dark-gray. Fresh. Nonvesicular. Trace silt from 450 to 460 ft.
- 450 , ';. .
3.,;, , x
~. i
_ . l 20- , .v : A ,.:.,* .,.; ,.
- 460 -l,.*. >
['. .,. ,* .. .. BASALT. Olive-gray. Fresh. Trace silt. Nonvesicular. 1
, r. . - J 1W Y r:GURE PUGET SOUND POWER & UGHT COMPANY LOG OF DRILL HOLE MJ-1 SKAGliI HANFORD NUCLEAR PROJECT asi.14-44
DRILL HOLE M1-1 Page.2_ of L l U* * ** th o Lithologic Description g , go Unit 10 - - w, * . . .
,, BASALT, as above. Local calcite mineralization at 465 to 470 ft.
-470 'f ; . , *.
5
....~.
,a w.
0- ** *
.a .<
6 ,*.,e.,<
.., . . , 1
- 480 . .'* * !*'-
,'..a* ,.,.,
Tem s,.*: ,' 1 *.'.'.
- 490 ***.
- 2 .*. / ." .
., ,. ) ;
P *,*** kBASALT. Olive-gray. Moderately weathered. Vesicular. Vesicles filled /
*Iwith
. , .yellowish-green
*,.' clay. /
- 500 7**1
%a
,,,,, M6 : Sandy clayey SILT to sandy silty CLAY. Light-olive-gray.
2 *~O* i Yt7. m.
.A
- l; CJayey silty SAND. Light-olive-gray. Local pyrite cement. Very-fine- to y 7 2 r medium-grained. Angular to subangular.
-r.sp.t
- 510 O
w SAND. Light-clive-gray to yellowish-gray. Fine- to coarse-grained; Ter [ ;<c mostly coarse-grained. 3 to 5% mafics. Angular to subangular. 1
- 520 S
3 ( SAND, as above, with pinkish-gray to light-greenish-gray CLAY fragments. 3 t4
-530 ~ ~ ~ - - - ~ ~ - - - - - - - - - - - - ~ ~ - -
4., g SILT, with CLAY f ragnents and SAND. Light-olive-gray; pinkish-gray j and light-greenish-gray. Silt tuffaceous. Clay with waxy luster. t E. g.....l ; , : l. BASALT. Brownish-black. Highly vesicular. Many vesicles filled with
-540 clay. Caved sand silt, and clay fragments.
,'./ .' . * ,
c ...
. ' 'R "(
J 5W
. PUGET SOUND POWER & LIGHT COMPANY Y FIGURE LOG OF DRILL HOLE MJ-1 SKAGIT I H ANFORD NUCLEAR PROJECT pag,,a.aa
DRILL HOLE m-1 Pagelof1 E * *
- th
- g Lithologic Description Unit
.a***
K < . . , . .
. f ,. , ., <
- 660 . , . , . , ... BASALT. as above.
*'f,,
4
'/.!.* f'-.
- so- * '"
S,,,,./>,
.+
- 560 '** Tp 3' , ' * , * , ' . ' . '
A,,. ..- BASALT. Dark-gray. Fresh. Nonvesicular from 560 to 570 ft. Minor L',**,**,*,' vesicles at 570 to 573 ft. 3'.***. A . , ,* ',, * .
- s7o 7
-se.7-E0H
$73' i
cv PUGET SOUND POWER & LIGHT COMPANY FIGURE LOG OF DRILL HOLE MJ-1 SKAGIT I HANFORD NUCLEAR PROJECT - as ,,,4 4 4
DRlLL HOLE m> SAMPLE TYPE PageI _ of _ $. Project No : c3-1036 @ Cuttings Elevation : 470.2 ft. 95 E Core, Number indicates % Core Recovery Total Depth : 425 ft. C 2015
- XRF, With Sample Number Coordinates : NW M W * ' ^'" P Chemical Results Listed in Table 2R-1 Date Completed : C /' /"
Unit Column Refers to General Stratigraphic Divisions identified Within the Site Area : M - Missoula ll! - Ringold. Cycle ill B - Basalt,Undif ferentiated PM - Pre-Missoula EM - Elephant Mountain Member 11 - Ringold. Cycle 11 RR - Rattlesnake Ridge interbed IV - Ringold. Cycle IV I- Ringold. Cycle 1 P - Pomona Mernber 0 Elevation Depth ed' d Uthologic Description Unit Ot.ust) (feet) W s@ 4 470- 4 7 l , . j.j. . Cravelly silty SAND. Medium-light-gray. 751 basalt grains. Coarse-io p .' ta very-coarse-grained. 2 60 +
~_
Crave 11y silty SAND to silty sandy GRAVEL. Medium-light-gray. 751 M.f basalt grains. Coarse- to very-coarse-grained.
) dip 1 ;'
f,*; I 460-- 10 ,, i 7
* ' / *}avery-coarse Crave 11y silty SAND. Medium-light-gray. 75%
grained; mostly medium-grained. basalt grains. Medium- to M 7 ',. '.a P a y, S Gravelly sandy SILT. Medium-gray. Cravel 60% basalt clasts.
~
M.M 450-- 20 - m J SAND. Medium-dark-gray. Medium- to very-coarse-grained; mostly coarse-
;p .
grained. 70% basalt grains. Trace silt.
, G .; }
I l; } c
*o; 440-- 30 gl?e. Gravelly silty SAXD. Moderate yellowish-brown grading downward to yellowish-gray. Moderately well to poorly sorted. 5 to 10% mafics,
...{'
4 j :. 1 increasing with depth. Micaceous. Angular to subangular.
-- 9 .
_ s. 430-~40 3.R
, ,*o i .e-
'g, Crave 11y SAND. Yellowish-gray. Very-fine- to fine-grained. 5-7%
-_ mafics. Angular to subangular. Gravel 20* basalt clasts. Trace
- 9.- silt at 45 to 50 ft. p..
s .q 6 .' f e 420-- 50 , ,p Gravelly silty SAND to sitty sandy CRAVEL. Light-olive-gray. 10 to 14
]p(p'i
. e, .j e, mafics. Tine- to coarse-grained. Gravel 25 to 30 % basalt clasts.
d ', 6 * .?
?
,Y*
Silty sandy CRAVEL. Moderate olive-brown. No cement rinds. Silt
',' .' adheres to clasts. Sand fine- to medium-grained.
410-- 60 7
- Crave 11y silty SAND. Dark yellowish-brown. Tine- to medium-grained. i 3 h.#15%
8 's mafics. Silt adheres to grains. Subangular to subrounded. _- 5.b , wv PUGET SOUND POWER & UGHT COMPANY FIG'JRE SKAGlii H ANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-2 s.:4 4e
DRILL HOLE m-2 p.ge.2 _ of _c_ D th o gc Lithologic Description Unit
- l .
2 f' Gravelly silty SAND as above. Micaceous. Ferruginous stain. Tine-400-- 70 'f.'.)4 ?t medium-grained; clasts. mostly medium-grained. No cement rinds on gravel
, *11 .
x . .- _ . 'f e I ': pn
! I Silty SAND. Dusky yellow. Very-fine- to medium-grained, mostly mediur-3 lI ql JJ .l. .grain ed. 5 to 7 % mafics. Large muscovite flakes.
39i-- 80 g e l ',j i - Oravelly silty SAND. Dusky yellow. Very-fine- to medium-grained; mostly M e.4 very-fine-grained. 2 to 3% mafics. No cement rinds on gravel clasts. _- g.d,~ M Gravelly clayey SILT to gravelly silty CLAY. Yellowish-gray to dusky 2Qs] yellow. Cravel probably caved. E~fsi 380--90 , ,,
, , , Crave 11y SILT. with CLAY fragments. Yellowish-gray. Sand very-fine-O g j/u grained.
el
,.l'e 4
J 3 ,M 'l . SILT. with CLAY fragments. Yellowish-gray to 130 ft.; yellowish-gray 1 to dusky yellow from 130 to 140 ft. Trace gravel at 100 to 105 ft. 370-4 00 Clay fragments decrease with depth. 5 d
- i. .&il,!$q T
' h g ,1 . ,1 360--110 j,h$l. ;
ih,l
- "t1 i '
l' l ,':1 , ' I 117
-- il H' ij 7
-li4...h, i
350--120 J 'j ,~ ,1
, 3"ll h ENgj l' i ih iri 7 1l ..
m , 340--130 m
^
l 7]jl .l!!. l '! I 1 ~ g, 3 $
^
330 -140 Ol6 ,:
,,,3 l, SILT. Yellowish-gray to dusky yellow. 9 5 'i l li i i 64
-_ Q h
.< 9, , t 4
(Wv PUGET SOUND POWER & LIGHT COMPANY FIGURE SKAGIT i HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE W- 2 aa1.1a-ae l
DRILL HOLE 'U-2 Pa ge_.3 of .i_ ( e- 6*p 9 p te n Und
~
igl . l . [ 0,l Sandy SILT. Yellowish-gray to dusky yellow. Sand very-fine-erained, p 'j )l ' Trace clay fraemente. 320---150 , n 4 1 Silty SAND to sandy SILT. Duskv vellow. Very-fine- to fine-grained 11 . 4 2-3% mafics. Angular to subangular. L I ,
- ',[
2 l .A. . . 310--160 .. Silty SAND. Dusky yellow grading downward to light-olive-brown.
'. l }. Very-fine- to medium-grained; mostly very-fine- to fine-grained. 11?
2 l- I. .c - : 3 to 5% mafics. Angular to subangular.
- f. .
e } 3A ' g_ :. 300 -- 170 f Sandy $1LT to silty SAND. Dusky-yellow. Sand very-fine-grained. a )p g' *'Clayey ,; in part. sj 7
.!'lj
.j h,{ Sandy SILT. Yellowish gray. Sand very-fine-grained.
,,,_ _10 cf'!
, . , .qj_
j i 7 .,
" s'e , ; 1.*
, Crave 11y SAND. Light-olive-gray. Fine- to coarse-grained; mostly fine- to medium-grained. 15 to 20% mafics. Sandy cement rinds on 1-u?
. e some gravel clasts. Trace silt at 185 to 190 f t.
T
^ .t e...
6 . 280- ~'*O Yy *,' ;-, Sandy CRAVEL to gravelly SAND. 45 to 50% basalt clasts. Sandy cemr.nt 54 ; f r :q, rinds on some clasts. Sand yellowish-gray; mostly medium-grained; Tal,'f;'; 7 to 10% mafics.
,- h
'5;s
- Crave 11y SAND. Light-olive-gray. Medium-graired. Micaceous. Sandy 1-b?
--'e;.' cement rinds on some gravel clasts.
270-- 200 M e-7 @,. .-* * . ' Sandy
. '. clayey CRAVEL. Clay light-clive-gray; possibly weathered
" basalt clay.
- u. . :[. %..,. ,
~_ ::. . . t,- - - - . _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ . _ _ _ _ _ _ _ .
3 . ,* .Y,*'. BASALT. Olive-gray. k'eathered and vesicular at 205 to 210 ft. N *, .*: : .;. 260-- 210 ,,.,. 7;,' ' .
- BASALT. Dark gray. Moderately fresh. Vesicular. Some yellowish-
.,*',**6
, green clay in vesicles.
7
- ,. j;.
Tc=
~*
250-- 220 , w m c >
.,,. g l
*
- 7 9
__- ..[.**. '.'- ) .-
,c u :,
h> PUGET SOUND POWER & LIGH COMPANY FIGURE J
. SKAGIT i HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-2 a1.i4-4e
F MJ-2 Pagel of tt._ DRILL HOLE ! Elevetien Depth Y Lithologic Description Unit poet-McL) (feet) one'Ysc
*. , .l. l ,
240- - 230 ;',0 l,* *,
.. .. 1.'e s t he r e d . Vesicular. some 7' BASALT. Hedium-dark-gray to 255 ft.
f ,*f.f,. .' vesicles filled with yellowish-green to white clay.
-- l.*..:* ,\
l .-* 1-230---240 ; y ,, *
- x ... .. . =. .
2 f, l .,'., 7- .*.i.'.,.*, 220- ~200
- 3. . * * , *, '
r i. ,.*. ***s ; y * * * , *, BASALT. Dark-gray. Tresh. Minor vesicles to 265 ft. Minor clay
*,2.,**, (caved?).
'y , *
- 2,'f Tem 210- - 260 '.,;,
7 * *, ., ... '
. :::l ,.
200- " l.',* . , *[ BASALT. Dark-gray. Fresh.
. Nonvesicular. Local pyrite or calcite
[ ., *,,* mineralization on some surfaces. Minor vesicles from 270 to 280 ft.
*f., and from 290 to 300 ft.
6 ,* f .
.;* /l; 7
190- -280 , ,[ ,j
,f.',...*.
... , l., * .','
7 w 180-- 200 .,.
.' [.,':* ;
r m ... 7 ..;, ; no-- 300 -' , * . *.:. s4
, . . . . .. 1 t.
N _- ,._ . . * ~ . a ww AW FIGURE PUGET SOUND POWER & LIGHT COMPANY LOG OF DRILL HOLE MJ-2 ast.14-4s SKAGIT f HANFORD NUCLEAR PROJECT
DRILL HOLE MJ-2 Page.1_ of.$ Depth
- k Utholode Description
'
- l" ,,c@ c Unh 2 *'.*** .
' * ,' BASALT. Dark-gray. Fresh. Nonvesicular. Local calcite or pyrite on
, ,', y*. some surfaces from 320 to 330 ft.
160-- 310 e, a . , , l v :.. 1.',. '.'
-- ',. *
- l .'.
2 . ; * '.:.
, .. .... . Tee
~*
150- - 320 , , ,. ,y 7
' -,;1 .. Y.',
.=.*,-
[ *.'.'.'.*.
'*Ia
- I BASALT. Dark-gray. Vesicular. Vesicularity increases with depth.
140 --330 ,* .*.' .. .vesicles ,' at 335 to 340 filled with green clay.
.q' 6 m -me,,,,, ----------,,,,,,,m , , , , , , , - - - - _ ,
O, , /,
-- . . l .,.
7 ~..- 130- -340 g 7FM
~
P. 20 Clayey SILT to silty CLAY. Light-olive-gray. _- Mt.1, _
%:M a+
120--oSO ,.g, Yil' l ib' SILT to clayey SILT. Grayish-yellow-green. Tuffaceous.
~~
Ter i10- -360 , KI ll i Clayey SILT. with CLAY and tuf faceous fragments. Pale olive. h~I,, g YIij'! _i l hl6 ! 100 - -370 gi ' i,{' ,,, i l s $h.}l
&u
,o_ -3e0 J!lI li; 7 kt I
_- ,. If M k* tW Y FIGURE PUGET SOUNO POWER & UGHT COMPANY LOG OF DRILL HOLE MJ-2 SKAGIT I H ANFORD NUCLEAR PROJECT 231.14-4s
DRILL HOLE M3-2 Pa geJL_ of .f.__ E' , ' " Depth b e\ Lithologic Description Un WeL) (feet) c,t
- 7 d'il Claye, SILT. as above. Pale-olive to grayish-olive. Vesicular Ii basalt clasts in sample at 395 to 400 ft.
Ter 80--300 .
~
f t .J p
-- i, l r.F
.',~.".'.
70- - 400 la ,. ,' , ; _s , , . ..
-.,, **. , BASALT. Dark-gray. Moderately fresh. Vesicular. Some vesicles 1, . , . , * . * , filled with green clay. Caved material from Rattlesnake Ridge
**** interbed from 405 to 420 ft. Bast 1t extremely vesicular from 415 60- - 410 .. ., to 420 ft.
i , * . * , ' .. . Tp
, ...*s a'.' '
a-,::,. , 60--420 .'...* < 2
- ....., . ~... ~ . ' .
45.2-- Lon 425' 1 mA AMI PUGET SOUND POWER & LIGHT COMPANY FIGURE SKAGIT / H ANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-2 2as.s4-4e
DRILL HOLE S-3 823-1036 SAMPLE TYPE Page L. of ~4 Project No . CWim Elevation . 468.5 ft. 95 E Core, Number Indicates % Core Recovery Total Depth : 273 ft. N451.378.18; E262.629.38 C2015 O XRF. With Sample Number Coordinates : Date Completed : A/26/82 Chemical Results Listed in Table 2R-1 Unit Column Refers to General Stratigraphic Divisions identified Within the Site Area : M - Missoula Ill - Ringold. Cycle til B - Basalt,Unmerentiated PM - Pre-Missoula 11 - Ringold. Cycle il EM - Elephant Mountain Member RR Rattlesnake Ridge interbed IV - Ringold. Cycle IV I - Ringold. Cycle 1 P - Pomona Member Elevation Depth od' e\ 400 Lithologic Description Unit (f t.ustl (f eet) M8
- g'.flfd Silty sandy CRAVEL to gravelly silty SAND. 50 to $5% basalt clasts. Sand hi '{
d' yellowish-gray; very-fine-grained; angular to subangular.
. -
- r: Crave 11y SAND. 75% basalt grains. Very-coarse-grained. Angular to 2 ' 'o' L ' subangular.
.; a .
l i
-'O W
,sa . b M m:. .-:v
_ )),FJO
'*N () Silty sandy CRAVI'L to gravelly silty SAND. 50 to 75% basalt clasts.
x.* . Sand poorly sorted; very-fine- to very-coarse-grained; 45 to 60% basalt y *,. M.h grains; angular to subangular. 450 -
~20
^
Nh
;tY?$$*
Dd." 2 ' N[fM[
~
; (.?. W d
7 .t'e ?py 440 -
~
b' j ., Cravelly silty SAND. Yellowish-gray to dusky yellow. Very-fine-
- 30 grained. <1% mafics. Angular to subangular. Gravel <45% basalt
'e,J. 8;. q clasts.
T-w t I f ;.f; i
- .a -Z 6...4.Q ...
430- 2" t,
- 9 Silty sandy CRAVEL to gravelly silty SAND. 20-25% basalt clasts.
- 40 f.* F ,'
h No cement rinds. Sanc' moderately to poorly sorted; 5-7% mafics; subangular to subrounded; yellowish-gray to dusky yellow. PM 3 * ' fyl. '
^
.fl.k
*fj Gravelly silty SAND. Yellowish-gray to dusky yellow. 7-10': mafics.
7
- g. Very-fine to medium-grained. Angular to subrounded. Gravel 25%
basalt clasts; no cement rinds. 420 - , j?.j
- 50 r
~T-T 2 'n.*
y
.,,1 lJi J ? Silty sandy CRAVEL. <50% basalt clasts. No cement rinds. Matrix g light-olive-gray to moderate-olive-brown. Clay at 55 to 60 ft;
,,.[gy,(./',f g . g possibly weathered basalt clay. 7
~
410 - GT.-
~ 60 S BASALT. Oive-gray. Weathered. Nonvesicular.
..* ..[....'. >
. j tv PUGET SOUND POWER & LIGHT COMPANY FIGURE SKAGIT l HANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-3 s a s .s 4-4c e
DRILL HOLE MJ-3 Page 2,_ of ,i,_ 0*"*" Depth Lithologic Description (feet- 0c Unit 6s80 (feet) gt*9 u ..,... 400- . , * ,' , BASAL.T. Olive gray. Veathered. Silt and clay at 70 to 75 ft.
- 70 .',.a., " ' .
7 [ , .., ,' *, BASALT. Medium-dark-gray at 75 to 80 ft. Dark-gray from 80 to 135 ft. 390- ' . * . . . Fresh, vesicular to 133 ft. Some vesicles filled with yellowish-green or
- 80 . . ' , ' , ' white clay.
m S 9,. . * * . .,. an.
.P .
g ..** 380- '.*,'.'.',
- 90 ' , ,* ' ,. * ' , '
r . , ,.' ,.***
, *a c
c ...',f..'.' .> 370- , . ,',. ; *,
-100 ' .* ..' ' Tem 7 < * . ' l ,'
5 ...,., 5
,4.. .. a
- 360- * * **,
. . a ..
-110 . *.
7 350- Pf* .'. . i
-120 -
l I* , ** a. .',l. . W '.,'..***. 340- *. .
- 130 l *** . .,
m . D *4 2 . , e. * . ., , , a. m ..'.,.. l'.". = 330- '.,**.*.
-140
. BASALT. Dark-gray. Fresh. Nonvesicular. Calcite en f racture surf ace at
.*'., 140 to 145 ft.
T.....',
.. a k
. . . ..a
..... 4 f 3
\p s
. _j 6 t, g, f' PUGET SOUND POWER & UGHT COMPANY m URE SKAGIT I H ANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-3 2 31.14-4 c
': . _ ,. .. , ..; a :. . *
- . L L. n - : : .w. ' ~ 's L. ? = . ..; ; ?. :: - s ,1 ~ -
L- c .' u '
-.-^J.,*. .
1 l DRILL HOLE U-3 Pa ge.l_ of ./s._. 1 l g ." Depth
- go Uthologic Description Unit 7 ' , * , ' . ' , *BASALT.
~
.' Dark-gray. Fresh. Nonvesicular. Calcite on fracture surface 320- *. . , ' * * . at 170 to 175 ft.
-150 '. * * *. * /
M '. .b, ;, "',:
~ . ,
2 .***,., 3to-
- 160 , . ' , f, ' , . ,
+
* /a '.'.,',
2 .'*,,,' 300 -
-170 L- *;,:.:.: .
E*
~
****.. BASALT. Medium- dark-gray from 175 to 185 ft. Fresh. Minor vesicules 200- ~ ,.*.* ,' . ' at 180 to 185 ft.
-180 -
.t..*....**.
?
. .',l
,, t ',. ' ' ,
. . . ~. :
vsm Xi !M,.; E3*. 7. $ Clayey SILT to silty CLAY. Light-olive-gray. Caved vesicular basalt 280-
- 190 7M 4m clasts.
i Wh* T _% ihd[
@ q:
-J i- ' l ' ' :
5 l i Clayey SILT. Light-olive-gray. Tuffaceous. 270- N. , . i i
- 200
~
p %_. . . - Clayey SILT to silty CLAY. Light-olive-gray. Tuffaceous. Ter E-i% *L M. .. . .1 c:f 7ET m.- Silty CLAY to clayey SILT. Crayish-yellow-green. Tuffaceous. 260-
- 210 4*: ].
g
- d Sandy clayey SILT to sandy silty CLAY. Grayish-yellow-green.
2 pWf g Tuffaceous. _ W5 Was Sandy silty CLAY to sandy clayey SILT. Crayish-yellow-green. 260-22 m~c. w v$ Tuffaceous.
-220 *#r y h b
Sandy clayey SILT. Grayish-yellow-green. Tuffaceous. Sand very-fine-
. grained.
; Q), ,
i
- .td _f4' '
21 % PUGET SOUND POWER & UGHT COMPANY FIGURE SKAGIT i H ANFORD NUCLEAR PROJECT LOG OF DRILL HOLE MJ-3 ms1.s4-4c
DRILL HOLE M-3 Page.i_of.i._
'" *\ Uthologic Description Uy Unit teou (Depth f##t) glo I
.I Sandy clayey SILT, as above. Ter
$ d4e 'f', -
240- I - - - - - - - - - - - - - - - - - - - - - -
-230 ,
s, ,, 2 ,.a.'.
,, v, : *
, ' .* , BASALT. Medium-gray grading downward to stdium-dark-gray. Moderately 2 *' fresh. Vesicular. Some vesicles filled vith green or white clay.
230- **
. ,: ,.*'* f*
- 240 a ,' f .*
- e w , , . ,..
'iS. ,,i{:
a 1 220- ,l.,l.'.=.
. }
-250 BASALT. Dark-gray from 245 to 260 ft. fresh. Vesicles decreasing. I j , .'//,. * >Calcite
./ crystals at 250 to 255 ft.
u '.','.'.',' Tp m
,,.. ..=...
1, .*,*,*. 210- p*...<
- 260 , ,'. ! * /,
n.*.,l a c.,.'.'.'.
. , y, ** BASALT. Grayish-black from 260 to 270 ft. Fresh. Large vesicles at
, . ' . , .265 to 270 ft. Increase in size of plagioclase phenocrysts at 260 to 7
u .- ' *, * ',,' * '265 ft. 200- *.....
- 270 . l. l
- 196.6-EOH 273' 4
>1 s
%y, s W%I PUGET SOUND POWER & UGHT COMPANY RWRE LOG OF DRILL HOLE MJ-3 SKAGIT i H ANFORD NUCLEAR PROJECT at.t4-4c
TA>aea& COQAs<een $1s>un.es .2 St. /s/ - sn 43/. /d - 5 0
.231.IJ-sc.
Ann 231. id - S b
N 5 93 MJ-1 73 m^ v~_ u, (Proj.100'E) % (800 g g ................g
- siis av sn If( .~.p - - - - -_ _ I-u s II Ill/ g 0- I- u ' Te" 1-t/ Tem -
-o $*
- ]>
-- Tp Ter/
a e 888 . 500 f t. E
- 5 ",x. '
--500 Scale EXPLANATION W MISSOULA FLOOD GR AVELS PM PRE-WISSOUL A FLOOD GR AVEL S RfMGOLD FORM Af TON IV UestT tv Its UesET let 88 UtslT 88 6-u UNIT t - uppee 8-b UNIT I - D...I COLUwelA RtVER B ASALT GROUP Tm ELEPHANT WCUNTAIN uf uBER T ., R ATTLESNAetE R80GE INTERBED To POWONA MEMBER
. o. . a. i . i c . . c i n. . ... u. . . .. .
..e e, .- w.. . .. . F i... G. . . . .
- ,- __ u,..... ., ... . ... . ..<,
NORTH-SOUTH GEOLOGIC CROSS SECTION - DRILLHOLE 93 TO 73 Figure 231.14-6
GEOLOGIC CROSS SECTION LINE 8C Figure 231.14-7
'Tpp '
I ' I W LINE 8C E o 600- - 600 n
$ MJ-3 us MJ-2 us MJ-1 g 2 - - -
pu; -- ^- 400-w _ 400 2 pu w 11 7 7
$ Tem
- 7 E 200-
- w 9 er *--------- II - 200 m d Tem o Tp g.b d To o a 0- ;
, Tp O ,
3 2 -- *
-200 *
-200 t
O t 4009 Scale Feet Horizontal = V artical EXPLANATION M WISSOULA FLOOD GR A VE LS 5 PW PRE-MISSOUL A FLOOD GR AVELS RtNGOLD FORWAf t0N IV UNIT IV 111 UNIT til it UNIT 61 1- u UNIT I - uppet t- b UNIT I - base.
- COLUMBIA river B AS ALT GROUP Tem ELEPHANT WOUNT AIN ME MBE R
=
T ee A ATTLESN AKE RIDGE NTERBEL /\ Tp POWON A MEMBE R A4 l: ,I
! c,. .S i..n ai ..ni.e ..t. e e n u ...wie a
and Pre-w. owia ricoe G,...i.
.-9--- Inferred or endeterminate contact NOTE Unit des gnat ons are ovestionee shere identif; Cat 0n Ot unit 1. vncertain ii Golder Associates
(,.,,,.. .. . . , .
10115/82 l
-e f EI i
5 u I*$
\' /
) \
W
)
G f 8 7 7 Y w s s s [
; i i
) s n;is I r l
I - l/f
/ a e
j " t /.
/ '
V ' 3 %
.l 1
} v I
I 1 I PuGE7 SOJND POWER & LIG=T CowpANY SKAG:t i M ANSCRD NUOLE AR PROJECT PRELIMINARY SAFETY 6 AN ALYSIS REPORT
.y GEOLOGIC MODEL OF GRAVITY LINE SC FlodRE 231.14-0 ,
AWWENDMENT38 7, e
S/HNP-PSAR 10/14/82 QUESTION 231.15 Provide a table and/or other device showing the relation-ship between the various site area lithologies and velocities (downhole, crosshole and refraction). RESPONSE:- The downhole velocity profil s presented in Appendix 2K and 2L have been annotated to indicate seismic velocities j% for the near-surf ace layers as determined f rom surf ace refraction and crosshole measurements together with'the identification of the stratigraphic horizons as obtained from the boring logs prepared by Golder Associates and
-presented'in Appendix 2R. The correlations observed on the enclosed annotated velocity profiles (Figures 1 through 6) are shown schematically on Figure 7.
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