ML17275A456
| ML17275A456 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 12/31/1979 |
| From: | Farooqui S SHANNON & WILSON, INC. |
| To: | |
| Shared Package | |
| ML17275A455 | List: |
| References | |
| NUDOCS 8007250393 | |
| Download: ML17275A456 (124) | |
Text
EVALUATIONOF FAULTING IN THE WARM SPRINGS CANYON AREA SOUTHEAST WASHINGTON prepared for WASHINGTON PUBLIC POWER SUPPLY SYSTEM under the direction of UNITED ENGINEERS & CONSTRUCTORS INC.
-Contract No. 44013, C.O. No. 38, Task-1
- December, 1979 by Saleem M. Farooqul SHANNON 8, WILSON, INC; 2266 S.W. Canyon Rd.
Portland, Oregon 97201 80(; 72503"S
I I
I I
I
TABLE OF CONTENTS Page INTRODUCTION 1.1 'UMMARY AND CONCLUSIONS 1.2 PURPOSE AND SCOPE II 1.3 METHODS OF INVESTIGATION 1.4 ACKNOWLEDGEMENTS STRATIGRAPHY 2.1 YAKIMABASALT (MIOCENE) 2.2 QUATERNARY UNITS STRUCTURE
- 3. 1 WALLULA FAULT I
- 3. 1 ~ 1 Main Wallula Fault Zone 3.1
~ 2 Quaternary Faulting 3.2 EN ECHELON FAULTS 3.3 FOLDS TECTONICS 12 CAPABILITY OF THE WALLULAFAULT 14 REFERENCES CITED 15
I
LIST OF FIGURES Figure No.
Index Map, Warm Springs Canyon Area.
2.
Geologic Map, Warm Springs Canyon Area, Southeastern Washington.
3.
Geologic Section A-A'allula Fault Zone.
4.
Geologic sketch of faulted colluvium in the Wallula fault zone near Warm Springs.
5.
Aerial photograph No.
WRH 1-7, dated 3/20/69.
Arrows show trace of,. topographic lineament.
6.
Regional Structural Map.
f 4
1.
INTRODUCTION
SUMMARY
AND CONCLUSIONS The Wallula fault is a wide, complex zone of faulting that extends along the north flank of the Horse Heaven Hills anticline for more than 30 miles.
The fault is predominantly a right-lateral, strike-slip fault with some dip-slip component.
The average vertical displacement is estimated to be 200 to 300 feet.
The net-slip along the fault has not been determined because of its complex geometry and kinematic relationships.
The fault has displaced flows of the Miocene Grande
- Ronde, Wanapum and Saddle Mountains Basalts of the Yakima Basalt; Quaternary colluvium and faulting of Touchet beds is considered likely along the "linear".
The Wallula fault is a capable fault, which exhibits evidence of recurring movements since Miocene time.
Approximately two miles west of Wallula Gap, branches of the Wallula fault merge into folded structures with limited fau1ting.
In this western area, the faulting consists of short fault segments within the Yakima'asalt, separated by extensive unfaulted areas of Saddle Mountains Basalt.
- Thus, faulting in this region west of Wallula Gap apparently has not occurred since pre-Pleistocene time.
1.2 PURPOSE AND SCOPE This report presents the results of geologic studies accomplished in the Warm Springs Canyon area, near Touchet, Washington, to evaluate late Quaternary movement on the Wallula fault as reported by Bingham and others (1970) and to provide an evaluation of its capability.
In addition, an attempt was made to define the amount, sense of motion and tectonic framework of the Wallula fault.
The area mapped covers parts of the Horse Heaven Hills, and the Pasco and Walla Walla Basins.
The location of the study area is shown on Figure l.
The scope of the investigation consisted of a detailed field examination and mapping of the Wallula fault, and the Tertiary and Quaternary geologic units exposed within a mile-wide zone extending between Wallula Gap, Washington, and Raymond Gulch, Oregon (Figure 2).
The field study was accomplished during July, 1979.
E k
I
The report is organized into six sections.
Sections 2 and 3
describe the stratigraphy and structures of the mapped area, with special emphasis on the Wallula fault.
Section 4 presents an interpretive discussion on the tectonic framework of the fault.
Evaluation of the capability of the Wallula fault is presented in Section 5 and references cited are included in Section 6.
1 ~ 3 METHODS OF INVESTIGATION The field geologic mapping encompassed an area of approximately 30 square miles in parts of Wallula, Zangar Junction,
- Touchet, Lowden, Waterman and Smeltz, 7.5-minute topographic quadrangles of the U.S. Geologic Survey.
Because the investigation.was principally directed towards evalu-ating the Wallula fault, field studies were concentrated along a one to two mile-wide strip, centered along the trace of the fault (Figure
- 1).
- However, reconnaissance also was made of the adjoining areas and of some of the nearby structural trends in order to provide additional information for analyzing the tectonic framework of the Wallula fault.
Aerial photography flown for the investigations by Bingham and others (1970) also was obtained and studied.
1.4 ACKNOWLEDGEMENTS Field work was conducted by Saleem Farooqui, assisted by R.C.
Newcomb and R.J.
Deacon.
Mr. H.H. 'Waldron assisted in the preparation of the report and the report was reviewed by G.A. Davis and H.C.
- Coombs, consultants to Washington Public Power Supply System.
l.
E r
l E
l, t,
I
2.
STRATIGRAPHY Bedrock in the mapped area consists primarily of,lava flows of
,the Yakima Basalt, of the Columbia River Basalt Group of Miocene age.
The Yakima Basalt is unconformably overlain by Quaternary surficial deposits consisting of Touchet beds, Pasco gravel, colluvium, loess and alluvium.
The distribution of the stratigraphic units is shown on the geologic map, Figure 2, which is a compilation of information developed during this in-vestigation and from previous published mapping by Newcomb (1965> 1970),
Swanson and others (1977) and Washington Public Power Supply System (1977a 6 b).
Descriptions of the stratigraphic units mapped during this investigation are presented in the following paragraphs.
2.1 YAKIMABASALT (MIOCENE)
Flows of the Yakima Basalt that outcrop in the mapped area
- include, from youngest to oldest>
the Ice Harbor (Ti), Ward Gap (Tw),
Elephant Mountain (Tem),
Pomona (Tp) and Umatilla (Tu)
Members of the Saddle Mountains Basalt; the Frenchman Springs Member (Tf) of the Wanapum t
- Basalt, and the Grande Ronde Basalt (Tgr)
(WPPSS>
1977c; Swanson and others, 1979).
The Ward Gap and Elephant Mountain Members are exposed only west of Wallula Gap (WPPSS, 1977b).
The Grande Ronde Basalt is exposed only in Vansycle Canyon, east of Wallula Gap, and the Ice Harbor and Pomona Members occur only in scattered isolated outcrops.
The Umatilla Member, which forms extensive outcrops along the Walla Walla River, north of the mapped area, appears to thin and taper out southward.
The Franchman Springs Member is the most extensive basalt unit in this area, underlying the Horse Heaven Hills and the region east of the mapped area.
The Roza and Priest Rapids Members of the Wanapum Basalt are not present in this area.
Except for a small "interbed (Te) between the Ice Harbor and Pomona
- Members, tuffaceous interbeds of the Ellensburg Formation are not present in the area.
I I
2.2 QUATERNARY UNITS The Quaternary units in the area include glaciofluvial deposits of silt (Touchet beds) and sand and gravel (Pasco gravel) and deposits of
- loess, colluvium and alluvium.
These units are described briefly as follows:
The Touchet beds (Qt)
(Newcomb; 1965; Flint, 1938) are the fine-grained facies of the late Wisconsin glaciofluvial deposits (Bretz,
- 1925, 1969) in this area.
The coarse-grained facies of the late Wisconsin glacio-fluvial deposits include sandy gravel and cobbles of mixed lithologies informally known as the Pasco gravel.
The Pasco gravel was not observed east of Wallula Gap, but is present west of the Gap (WPPSS, 1977b).
- Layered, light brown and light gray silt and fine sand of the Touchet beds is the most extensive Quaternary stratigraphic unit in the area.
The Touchet beds are slack-water deposits laid down by the waters of the Spokane flood (Bretz, 1925; Allison, 1933).
. The type section of the Touchet beds is along the Walla Walla River, south of the town of Touchet (Flint, 1938).
- Locally, Touchet beds include some channel sand and gravel. It is estimated that the Touchet beds were deposited up to elevations of approximately 1000 feet.
- However, much of the silt above about elevation 600 feet has been removed by wind erosion and redeposited on the basalt uplands as loess.
Along the flanks of the Horse Heaven Hills, the Touchet silt locally includes and interfingers with basalt colluvium.
Large deposits of this reworked colluvium occur in sections 2 and 3, T6N, R32E, in the Warm Springs area.
Some incipient caliche development is also present in this "colluvial Touchet",
- however, the caliche is very powdery and silty and it appears to be unsuitable for age determinations.
The age of the Touchet beds is approximately 13,000 ybp (Mullineaux and others, 1978).
The Touchet beds are cut by numerous clastic dikes (Alwin, 1970; Brown, 1962; Jenkins, 1925; Lupher, 1944;
- Newcomb, 1962; and Shannon 6
t Wilson, Inc., 1974).
The dikes are sinuously vertical and locally show tree-like undulating branches.
They are 1-to 9-inches wide near the surface and gradually narrow towards the bottom.
The material filling the dike generally consists of silt and fine sand.
Some of the clastic dikes show complex and delicate sedimentary structures; e.g.,
graded and cross bedding,,and multiple vertical silt partitions ranging from thin laminae to 1/4-inch thick.
The Kennewick fanglomerate, exposed in the Wallula Gap trench
I l
a
(WPPSS, 1977a; Woodward-Clyde Consultants, 1978) was not observed in the mapped area.
Other Quaternary deposits in the mapped area include eolian silt (loess-Ql),
slope debris-(colluvium), flood plain silt, sand and gravel (alluvium-Qal), and volcanic ash.
Light brown loess of variable age mantles the upland slopes.
Locally, the loess interfingers with and is intermixed with colluvium.
The colluvium, consisting, of angular basalt fragments in a silty matrix, occurs on steep slopes underlain by the Yakima Basalt at shallow depths.
The colluvium has not been shown as a separate unit on the geologic map (Figure
- 2) in order to show the aerial distribution of the flows of the Yakima Basalt.
Young alluvium consisting of sand and gravel and re-worked colluvial deposits occurs in valley bottoms.
Scattered, small patches k
I of fine-grained tephra also occur in the mapped area.
1
3 ~
STRUCTURE The structural features of the mapped area include the Wallula fault, a system of faults en echelon to the Wallula fault, and a few folds.
These structural features are shown in Figure 2 and are described as follows:
3.1 WALLULAFAULT The Wallula fault is a complex zone of faulting that extends for several miles along the northern flank of the Horse Heaven Hills anti-cline (Figure 6).
This section describes the field characteristics of the fault and probable Quaternary ruptures associated with it.
3.1.1 Main Wallula Fault Zone The main Wallula fault zone consists of an 800-to 1000-foot wide, vertically-dipping breccia zone as shown on Figure 2.
East of Wallula Gap, the breccia zone is well exposed in sec.
12,
- T6N, R32E (informally known as the Slide), where the Walla Walla River impinges against it; and in a ravine in sec.
12,
- T6N, R32E.
East, of Vansycle Canyon, the topographic expression of the fault is subdued.
To the west, the fault forms a prominent fault-line scarp between Vansycle Canyon and Wallula Gap.
This fault-line scarp is characterized by a prominent linear escarpment with truncated spurs.
o 0
The strike of the fault in this area ranges from N60 W to N70 W.
The scarp is not present west of the Columbia River.
The fault zone includes tectonically fractured, brecciated,
- sheared, pulverized and mylonitized zones.
Generally, these zones are within the flows of the Frenchman Springs Member, but locally, the Umatilla Member is also involved in brecciation.
Relatively intact blocks of basalt also occur within the fault zone.
The cementation within the fault zone is I
highly variable.
Pods of cemented breccia rise above colluvium and form breccia pipes.
Wide bands (zones) of clay gouge also occur in the fault zone, but generally they are covered by colluvium except where they have been exposed locally by man-made cuts (WPPSS, 1977a).
The gray-brown and gray-green clay gouge is derived from the complete pulverization of basalt.
t R
I s.
5l I
The clay gouge is plastic and moist, it can be remolded into threads by a slight finger pressure, it is highly slickensided>
and it can be peeled-off into thin oblong discs.
0 Strong slickensided surfaces with horizontal to 10 NW dipping grooves and striations were observed both in the basalt adjacent to the fault zone and in the breccia zone.
An excellent example of grooves and striations is exposed in a road cut near the mouth of Wallula Gap (sec.
27, T7N, R31E; locality A, Figure
- 2).
Also in this road cut, a vertical 1/4-inch thick clastic dike, with vertical silt partings and sandfill, occurs in the shear zone.
The silt of the clastic dike, which is smeared on the slickensided surface of the gouge
- zone, shows horizontal striations, indicating some post-dike movement in the shear zone.
The Wallula fault trends generally parallel to the regional strike of the basalt flows.
South of the fault zone, flows of the Frenchman Springs Member dip 1 -4 N.
However, along the north side, flows dipping 0
0 30 -50 N occur near the fault contact.
These steep dips are exposed along 0
0 the Walla Walla River (sec.
12, T6N, R32E; locality B, Figure 2), and also in the Nub (a hogback hill in sec.
31, T7N, R32E), which is underlain by the Xce Harbor, Pomona and Umatilla Members.
These dips indicate drag along the fault (Figure 3).
The vertical displacement is estimated to be less than 300 feet in this area, as indicated by the faulted members of the Yakima 1
Basalt in the Nub (hogback hill).
East of the impingement by the Walla Walla River (sec.
12, T6N, R32E), the Wallula fault zone is covered by silt deposits of probable Touchet beds and is not traceable.
West of the Nub, in sec.
31, T7N, R32E, the fault splits into two branches - N80 W and N50 W branches.
The N80 W branch, called the 0
0 0
Wallula Gap fault (Bingham and others, 1970;
- WPPSS, 1977a and b) trends westerly across Wallula Gap for a distance of about 3 miles, where it merges into the north flank of the Jump-Off Joe anticline (WPPSS, 1977b; Jones and
- Landon, 1978).
A trench across Wallula Gap fault near Yellepit revealed, that at that point, the fault did not cut the Kennewick fanglomerate (WPPSS, 1977a)
(age 50,000 ybp, Woodwar'd-Clyde Consultants, 1978).
Approximately 4-miles farther west, undeformed flows of the Umatilla Member lie across the projected trend of the fault (WPPSS, 1977b).
f I
1
The N50 W branch trends northwesterly across Wallula Gap and 0
passes through an 800-foot wide breccia zone exposed in the first doubly-plunging anticlinal hill northwest of the Columbia River (WPPSS, 1977b).
Beyond this hill, the breccia zone and the fault are covered by Pasco gravel, and a series of slightly en echelon, doubly-plunging anticlinal hills lie along the projected trend of the Wallula fault.
This segment of elongate plunging hills has been called the Rattlesnake Hills-Wallula lineament (WPPSS, 1977b and 1977d).
Although some of these hills are locally faulted, no through-going fault, like the Wallula fault, is exposed at the surface.
3.1.2 Quaternary Faulting Quaternary faulting in the mapped area included a small fault showing colluvium in fault contact with tectonic breccia in the Wallula fault
- zone, and possible faulting indicated by a topographic linear in the Touchet beds (Bingham and others, 1970) that overlie the Wallula fault zone.
A fault zone of probable Quaternary age occurs in a narrow ravine in section 12,
- T6N, R32E (locality C, Figure 2).
The fault contacts were examined in detail after manually excavating slope wash in the side walls of the ravine.
ln addition, a shallow pit was dug.in the bottom of the ravine> where the fault, contact was located about 2.6 feet below the young alluvium of the ravine.
The location of this Quaternary fault is indicated on Figure 2, and a generalized composite view of the two side walls of the ravine is shown in Figure 4.
The narrow ravine, which drains north-ward is incised into a bench at an elevation of approximately 600 feet.
Although the bench is underlain by tectonic breccia of the Wallula fault zone, it is mantled by a thin cover of undifferentiated loess and Touchet beds (Ql/Qt).
The faces>
as exposed in the ravine walls, show a 45-foot wide 0
mass of red-brown colluvium bounded by two faults that strike N60 W and dip 0
0 45 -55 S.
The colluvium consists of angular>
2-to-=8-inch sized basalt fragments in a slightly cemented silt matrix that is in fault 'contact with tectonic breccia of the Wallula fault zone.
A greenish-gray clay gouge of moderate plasticity occurs at the fault contact.
The clay gou'ge ranges from 2 to 6 inches in thickness, and contains highly polished and slickensided surfaces.
Striations within this clay gouge have not been observed,
- however,
l kl'j II I
0 striations in the tectonic breccia zone show 0-5 degrees N60 W plunging striations.
Near the south fault, the colluvium includes some highly pulverized material of the Wallula fault zone.
The absolute age of the colluvium is difficult to determine from this limited exposure.
However, the weak cementation of the colluvium between the two faults, incised drainage, comparison with the uncemented colluvium and the loess suggest that the faulted colluvium may be pre-Holocene in age.
Also, the plastic nature of the clay gouge shows re-molding by possible repeated movement along these two fault planes.
Bingham and others (1970), while investigating projection of the Wallula Gap fault southeastward from Vansycle Canyon, observed a geologically youthful, curved linear feature on aerial photographs numbers WRH 1-7 (Figure 5) and 2-6, dated '3/10/69.
This feature (shown on Figure
- 2) was described as follows:
a geologically youthful, curved linear feature that seems to be a ground-surface rupture was observed and briefly investigated in the field.
- Here, the bedrock and the fault zone are mainly concealed by glaciofluvial deposits of the late Pleistocene Touchet beds and by Holocene loess.
The linear feature appears to slightly displace the Touchet beds but to be topographically subdued because of slight erosion and subsequent deposition of Holocene loess.
Although the nature and origin of the linear feature could not be determined definitely by the brief field examination, its topographic situation does not allow readily for its explanation as being a result of erosion or landsliding, or any other non-tectonic I
process'he trace of the feature crosses most of the drainage gullies and shallow valleys nearly at right angles and does not have an apparent relation to the pattern of stream channels.
The area is one of low topographic relief and low stream gradients, so'that rupturing associated with landsliding is not a likely cuase.
The present subdued vertical relief of the linear feature is a few inches to several feet, with the north side being generally lower than the south.
Toward the southeast end of the linear feature cattle have used it as a natural trail
1
except where it passes under a fence and the cattle trail swings away to a nearby gate."
"For all these reasons the linear feature appears to be a ground-surface rupture due to relatively recent tectonic fault movement along the Wallula Gap fault On the aerial photographs (scale 1:6,000) flown for the study by Bingham and others (1970), the linear feature stands out conspicuously as shown in Figure 5.
East of the fence line (sec.
3, T6N, R32E), because the area has been under cultivation since the reconnaissance by Bingham and others (1970)
> the linear is no longer visible on the ground.
However, west Cof the fence line, the linear is still visible in the topography, especially with low sun-angle lighting and moist ground conditions.
The location of the linear is shown on Figures 2 and 5.
The linear occurs entirely within the Wallula fault zone where it is overlain by Touchet beds.
Glass (WPPSS, 1977e) conducted an interpretation of the 1:50,000 (BPA-PSLG-1973) color prints, standard and enhanced LANDSAT imagery and 1:24,000 low sun-angle photographs (taken by him along the major structures) of the Hanford region including the Warm Springs Canyon area and made the following observations (WPPSS, 1977e; pages 2
R k-8 a -9):
The fre'shest appearing features are located at the mouth of Vansycle Canyon (Figures K-10 6 K-ll).
These features do not appear to have a large amount of displacement associated with them and the displacement does not appear to be Holocene.
The Morphology of this area suggests that those features are not tectonic but related to large-scale landsliding (Figure K-ll).
The location of the area in a region of demon-strated faulting, and the inability to conclusively associate these features with non-tectonic origin forces me to assume that the features trending east across the mouth of Vansycle Canyon to the Walla Walla River are faults."
Based on the observations made for this study, by Glass (1979) and in WPPSS (1977e),
and by Bingham and others (1970),
the linear appears to be the result of fault produced ground-surface rupture.
Faulting along the Wallula fault, zone appears to have been initiated sometime in post-Grande Ronde time (early Miocene, 16.5 mybp) and l
l
continued intermittently throughout Pliocene, Pleistocene and early Holocene, as recorded in the faulted stratigraphic units.
Recurring movements along the fault is suggested by the presence in the fault zone of blocks of healed and cemented tectonic breccia, by zones of highly pulverized and uncemented tectonic breccia, and by zones of plastic clay gouge.
3.2 EN ECHELON FAULTS Several northwest-trending faults (Figures 2 6 6),
en echelon to the Wallula fault, have been mapped in the area (Newcomb 1965 and 1970; Swanson and others, 1977).
Some of these faults have strong topographic expressions and form high, linear escarpments.
These faults occur only south of the Wallula fault zone, and their projected trends form acute angles with the Wallula fault.
Because of the pervasive surficial cover of loess, neither the en echelon fault planes nor their intersections with the Wallula fault are exposed.
However, the geometry of the escarpments produced by these en echelon faults show southeastward decreasing displacement:
they appear to be oblique-slip faults with the north side down.
A shear zone associated with one of the faults shows horizontal striations.
This shear zone is exposed in a quarry several miles south of the mapped area.
3.3 FOLDS Two folded structures (Figure 2), the Walla Walla syncline and the Divide anticline (Newcomb, 1965),
extend into and terminate in the mapped area north of the Wallula fault.
The Walla Walla syncline forms a large west-trending synclinal basin, the west end of which apparently termin-ates in the vicinity of the Divide anticline.
The Divide anticline is a south-plunging, upwarp that separates the Walla Walla Basin from the Pasco Basin (Newcomb, 1965).
4, TECTONICS The Wallula fault is a part of the Cle Elum-Wallula deformed belt (CLEW) as defined by Laubscher, 1977, that extends from near CleElum, in central Washington, about 126 miles. southeastward to near Wallula Gap in southeast Washington (Bentley and others, 1978; Kienle and others,
- 1977, Laubscher, 1977; Shannon 6 Wilson, Inc., 1978).
The CLEW includes a variety of folded and faulted structures, and coincides with the central part of the Olympic-Wallowa lineament (Raisz, 1945; Wise, 1963;
- Skehan, 1965).
The Columbia Plateau regions, like the rest of the Pacific Northwest, is considered to be under a regional north-south compression with the major principal stress in a horizontal plane.
This stress pattern is based on the orientation and geometry of the Yakima Basalt structures of Mio-Pliocene age (Wise, 1963; Laubscher, 1977; Waitt, 1979) and on fault-plane solutions of instrumentally-recorded earthquakes (Malone and others, 1975;
- WPPSS, 1977f; WPPSS>
1977g;
- WPPSS, 1977h).
Detailed mapping of the Wallula fault, during this and earlier investigations (WPPSS, 1977a and b),
has identified geologic features that lead to the following interpretation of the tectonic-kinematic framework for the Wallula fault.
The Wallula fau3,t appears to be a northwest-trending, oblique-slip fault.
This is suggested by several lines of evidence:
- 1) the consider-able thickness of the vertically dipping tectonic breccia zone in contrast to the amount of vertical displacement,
- 2) the steep bending of the basalt flows along the north wall of the fault zone, and
- 3) strong horizontal to 10 degree N60 -70 W plunging grooves and striations on the slickensided 0
0 surfaces.
All these features indicate that the Wallula fault is predominately a strike-slip (wrench) fault with a dip-slip component.
The geometry of the en echelon faults east of Wallula Gap and the. slight en echelon nature of the doubly plunging anticlines west of Wallula Gap (Figure 6), also indicate a right-lateral sense of motionon the Wallula fault.
The Wallula fault and associated en echelon faults (tension gashes of Riedel, 1929) appear to form a Riedel and conjugate Riedel shear pattern on a regional scale (Tchalenko, 1970; Wilcox and others, 1973).
I
Strike-slip faults, and thrust faults and folds are genetically
- related, inasmuch as these structures are generated under similar compressive stress regimes (DeSitter, 1956}.
However, with a reversal of the inter-mediate and minimum stress orientations, strike-slip faults may change into thrust faults and folds.
Strike-slip faulting produces an extensional component in a horizontal direction, whereas thrust. faulting produces it in a vertical direction.
These stress characteristics are evident in the overall geometry of the Wallula fault and its associated en echelon folds and faults (Figure 6}.
Horizontal extension is indicated by the en echelon faults, with the down-dropped blocks to the north and decreasing displacement to the southeast.
Vertical extension is indicated by the folded structures along the Wallula-Rattlesnake Hills lineament and Jump-Off Joe anticline (WPPSS, 1977a and b; Kienle, 1977}.
The amount of strike-slip along the Wallula fault could not be determined because of the complex kinematic relationship of the fault to the folded structures to the west and north.,
and to the faulted structures to the east.
I
5.
CAPABILITY OF THE WALLULAFAULT The Wallula fault is an approximately 30-mile long tectonic structure that trends northwesterly from Milton-Freewater to near Wallula Gap,(Shannon and Wilson, Inc., 1979).
Near'Wallula Gap, the fault divides into N80 W and N50 W branches.
The N80 W branch (Wallula Gap fault of Bingham and others, 1970) trends westerly for about 3 miles and merges with 0
unfaulted homoclinal slopes (WPPSS, 1977b),
The N50 W branch. trends north-westerly for about 4 miles across Wallula Gap and appears to merge into a series of doubly plunging, slightly en echelon hills located along the Rattlesnake Hills-Wallula lineament (WPPSS, 1977b),
Extensive areas under-lain by unfaulted members of the Saddle Mountains Basalt lie across the projected trends of these branch faults.
The presence of unfaulted basalt across the projected trends of these branch faults demonstra'tes that the western termini of these faults have been inactive, at least, since Pliocene (2 mybp) times.
East of Wallula Gap, however, Quaternary tectonic activity on the Wallula fault is indicated by the following observed features in the fault zone:
faulted colluvium of probable Quaternary age
- horizontal movement along a clastic dike of probable Touchet age (13,000 ybp)
A fault-like linear feature that appears to be due to a ground-surface rupture in the late Pleistocene Touchet beds (13,000 ybp) and possibly in Holocene loess clay gouge zones bounding the faulted colluvium, which suggest slow creep or recurring movements on the fault.
Based on these tectonic features, parts of the Wallula fault may have moved at least once in the past 35,000 years, and apparently, more than once in the past 500,000 years.
Thus, the fault is considered to be a
capable fault, in accordance with the definition of a "capable fault" in the seismic and geologic siting criteria for nuclear power plants (U.S.
Code of Federal Regulations, 1979).
l
6.
REFERENCES CITED Allison, I.S.,
- 1933, New version of the Spokane flood:
Geological Soc.
America Bull., v. 44, p. 675-722.
Alwin, John A., 1970, Clastic dikes of the Touchet beds, southeastern Washington:
M.S. Thesis, Washington State University.
Bretz> J.H.>
- 1925, The Spokane flood beyond the channeled scablands:
Jour.
Geology, v. 23, p.97-115, 236-259.
Bretz, J.H.,
- 1969, The Lake Missoula floods and the channel scabland:
Jour.
Geology, v. 77, p. 505-543.
Brown, D., 1962, Touchet clastic dikes in the Ringold Formation:
Hanford Atomic Products Operation Report HW-SA-2851, llpp.
Bingham>
James W., Londguist> Clark, J.,
and Baltz, Elmer, 1970, Geologic investigation of faulting in the Hanford Region, Washington with a section on the occurrence of microearthquakes by A.M. Pitt:
U.S. Geol. Survey, open-file Report.
Bently, Robert D., Farooqui>
Saleem M., Kienle> Clive F., Jr.,
and Anderson, James L., 1978, Structural elements of the Cle Elum<<Wallula deformed belt:
Abs. Cordilleran Section, Geol.
Soc.
America>
74th Annual Meeting.
DeSitter, L.U., 1956, Structural Geology:
McGraw-Hill Book Company, Inc.,
Flint, R.F.,
1938, Origin of the Cheney-Palouse scabland tract, Washington:
Geol.
Soc.
America Bull., v. 49, no.
3, p. 461-523.
- Glass, Charles E.,
1979, Preliminary image interpretation of the Warm
- Springs, Washington area:
Letter report, work in progress for Washington Public Power Supply System.
- Jenkins, O.P.,
1925, Clastic dikes of eastern Washington and their geologic significance:
American Journal of Science, 5th series,
- v. 10, p.
234-246.
- Jones, M.G., Landon, R.D.,
- 1978, Geology of the Nine Canyon map area:
Informal report no.
RHO-BWI-LD-6, Rockwell Hanford operations, prepared for the U.S. Department of Energy under Contract E 77-C-06-1030
REFERENCES CITED (continued)
Kienle,'r., Clive F.>
Newcomb, R.C.,
Deacon, R.J., Faroogui, S.M., Bentley>
R.D., Anderson, J.L. and Thorns, R.E.,
1977, Western Columbia Plateau tectonic structures and their age of deformation, in Tectonics and Seismicity of the Columbia Plateau Workshop; Basalt Waste Isolation Program, Rockwell Hanford Operations,
- Seattle, Wa., February 14-17.
Laubscher, H.PE p 1977'tructural analysis of post-Yakima deformation Columbia Plateau, Washington; Draft report, work in progress for Washington Public Power Supply System.
Lupher, R.L., 1944, Clastic dikes of the Columbia Basin Region> Washington and Idaho.-
Geol. Soc. of America Bull,, v. 55, p. 1431-62.
Malone> Stephen D., Rothe, George H., and Smith, Steward W., 1975> Details of microearthquakes swarms in the Columbia Basin, Washington:
Bull. Seism.
Soc. America, v. 65, No. 4.
Mullineaux, Donald R., Wilcox, R.E.,
- Ebaugh, W.F., Fryxell, R., Rubin, M.,
- 1978, Age of the last major Scabland flood of the Columbia Plateau in eastern Washington:
Quaternary
- Research,
- v. 10, no, 2.
Newcomb, R.C.,
1962, Hydraulic injection of clastic dikes in the Touchet
- beds, Washington, Oregon and Idaho:
Geol.
Soc. of the Oregon Country Newsletter>
- v. 28, no.
10 (abstract).
- Newcomb, R.C
, 1965, Geology and groundwater resources of the Walla Walla River Basin, Washington-Oregon:
U.S. Geol.
Survey Water Supply Bull. no. 21.
N Newcomb, R.C, 1970, Tectonic structure of the main part of the basalt of the Columbia River Group, Washington, Oregon and Idaho:
U,S.
Geol. Surv. Misc. Geol. Inv. Map 1-587.
t Raisz, E., 1945, The Olympic-Wallowa lineament; Am. Jour. of Science,
- v. 243-A, p. 479-485.
Riedel, W., 1929, Zur Mechanik geologischer Brucherscheinungen:
Centralbl.
f."
Mineral. Geol. u. Pal, v, 1929B, p. 354-368.
Shannon and Wilson, Inc., 1979, Tectonic Map:
Work in progress for Washington Public Power Supply System, under direction of United Engineers 6
Constructors, Inc.
Shannon and Wilson, Inc., 19'/8, Geologic Reconnaissance of the Cle Elum-Wallula lineament and related structures, by Clive F. Kinele, Jr.,
Robert D. Bentley and Jame's L. Anderson:
Report prepared for Washington Public Power Supply System, under the direction of United Engineers a Constructors, Inc.
REFERENCES CITED (continued)
Shannon and Wi'lson, Inc., 1979, Geologic Recon. of the area between Wallula
- Gap, Washington - Blue Mountain - LaGrande, Oregon. Region, by C.F. Kienle, Jr.> M.L. Hamill, and D.N. Clayton:
Report pre-pared for Washington Public Power Supply System under the direction of United Engineers 6 Constructors, Inc.
Shannon and Wilson, Inc., 1974, Supplemental geologic investigations for Carty West site; report on trenching and clastic dikes, Boardman Nuclear Project, Morrow County, Oregon:
Report prepared for Portland General Electric Co.
- Skehan, J.W.,
- 1965, A continental-oceanic crustal boundary in the Pacific northwest:
prepared by Boston College, Chestnut'ill, Mass.>
for Air Force Cambridge Research Laboratories, Office'of Aerospace
- Research, Bedford, Mass.,
AFCRL-65-904.
- Swanson, D.A., Wright, T.L., Gardner, J.N., Helz, R.T., Price, S.A.,
and
- Ross, M.E.,
1977> reconnaissance geologic map of the Columbia River Basalt Group, Pullman and Walla Walla Quadrangles, south-east Washington and adjacent Idaho:
U.S. Geol. Survey, open-file map 77-100.
- Swanson, D.A., Wright, T.L., Hooper, P.R.,
and Bentley, R.D.,
1979, Revision in stratigraphic nomenclature of the Columbia River Basalt Group:
U.S. Geol. Survey Bull. 1457-H.
Tchalenko, J
~
ST
, 1970, Similarities between shear zones of different magnitudes:
Geol.
Soc.
America Bull. v.
81> p, 1625-1640.
1 U.S.
Code of Federal Regulations, 1979, Title 10 - Energy; Chapter 1 Nuclear Regulatory Commission, part 100, Reactor Site Criteria; appendix A-Seismic and geologic siting criteria for nuclear power plants.
Waitt, Jr., Richard B., 1979, Late Cenozoic deposits, land-forms, stratigraphy and tectonics in Kittitas Valley, Washington:
Geol. Survey Prof. Paper 1127.
Washington Public Power Supply System (WPPSS),
1977a, Preliminary Safety Analysis Report, WNP-1/4 PSAR, Amendment 23, Sub-appendix 2R H, Chapter 4, "Geologic studies of the Wallula Gap fault as exposed in the trench", by Saleem M. Farooqui, Shannon and Wilson, Inc.
Washington Public Power Supply System (WPPSS),
1977b, Preliminary Safety Analysis Report, WNP-1/4 PSAR, Amendment 23, Sub-appendix 2R H, Chapter 5, "Geologic studies-Wallula Gap to Badger Coulee",
by Saleem M. Farooqui, Shannon and Wilson, Inc.
REFERENCES CITED (continued)
Washington Public Power Supply System (WPPSS),
1977c, Preliminary Safety Anlaysis Report, WNP-1/4 PSAR, Amendment 23, Sub-appendix 2R H-a, "Stratigraphy of the'olumbia River Basalt Group and Ellensburg Formation", by Robert D. Bentley, Shannon and Wilson, Inc.
Washington Public Power Supply System (WPPSS)>
1977d, Preliminary Safety Analysis Report>
WNP 1/4 PSAR>
Amendment 23, Sub-appendix 2R H, Chapter 7, "Reconnaissance mapping of the rattlesnake Hills-Wallula lineament, eastern Rattlesnake Hills> and Yakima Ridge",
by Clive F. Kienle, Jr.,
Shannon and Wilson, Inc.
Washington Public Power Supply System (WPPSS),
1977e, Preliminary Safety Analysis Report, WNP-1/4 PSAR, Amendment 23, Appendix 2R K, "Remote sensing analysis of the Columbia Plateau",
by Charles E. Glass.
Washington Public Power Supply System (WPPSS),
1977f, Preliminary Safety Analysis Report, WNP-1/4 PSAR, Amendement 23> Sub-appendix 2R C, "Tectonic evolution of the Pacific northwest, pre-Cambrian to present",
by Gregory A. Davis.
Washington Public Power Supply System (WPPSS)>
1977g, Preliminary Safety Analysis Report, WNP-1/4 PSAR, Amendment 23, appendix 2R J, "Evaluation of microearthquake activity in eastern Washington",
by Weston Geophysical
- Research, Inc.
Washington Public Power Supply System (WPPSS),
1977h, Preliminary Safety Analysis Report, WNP-1/4 PSAR, Amendment 23> appendix 2R L> "Nicro-earthquake survey and evaluation of stress orientation in central Washington",
by Woodward-Clyde Consultants.
Wise, D.U., 1968, An outrageous hypothesis for the tectonic pattern of North American Cordellera:
Geol. Soc.
America Bull., v. 74, p.
357-363.
Wilcox, Ronald E.', Harding, T.P.,
and Seely, D.R., 1973, Basic Wrench tectonics:
The American Assoc. Pet.
Geol. Bull, v. 57, no. 1,
- p. 74-96.
Woodward-Clyde Consultants, 1978, Paleomagnetic measurements of the Ringold Formation and loess units near Hanford, Washington and evaluation of age dating potential of Quaternary deposits near Hanford, Washington.
Report prepared for Washington Public Power Supply System under the direction of United Engineers and Constructors Inc., Philadelphia, Pen.
118
//
c r
)
OUCHET RLYER Richland
, Pasco
'o~
(
Kennenick:~(
(
i, i.
rrkttutk
/
~.L gyp~
Z
/Ihip]
~~l L.itiltnn Freenete+r HERMISTOH 1:500,000 SCALE IH MILES 20 WASHINGTON PUBLJC POWER SUPPLY SYSTEM HUCLEAR PROJECT HOS.
1
& 4 INDEX MAP WARM SPRINGS CANYON AREA PENDLETOH
- DECEMBER, 1979 UE 8
C CONTRACT 0 44013 SHAHNOH 5 WILSOH, INC.
GEOTECHNICAL CONSULTANTS
- PORTLAND, OREGON
- FIG, 1
SOUTH NORTH Loess (Grass covered slopes)
SILT (LOESS) intermixed with angular basalt fragments Colluvium Angular basalt fragments.
up to 1B-inch size in a
.red-brown, weakly cemented SILT Loess (Grass covered slopes)
Tectonic Breccia Cr 0
4y
. oO.~o.,o.O.o..-
~
o.0-4 O'Q:a.o.,o,o'.....~o.
~ o..'g.ooQ. y Alluvium Covered 0 '4+op'.oo.
'g o.
p'<S o~ a'g
'oo.p,o o o
'0:
~
0
~ oQ+'0:o:Oo oo TEST PIT
'Oo.
Tectonic Breccia 10 VERTICAL SCALE IH FEET 0
10 20 HORIZONTAL SCALE IN FEET VERTICAL EXAGERATIOH X2
.-0 'o$pop,..
Al luvium
.o: g'.-<p,. CREEK WASHINGTON PUBLIC POWER SUPPLY-SYSTEM HUCLEAR PROJECT.'HOS.
1 S
4 GEOLOGIC SKETCH OF FAULTEO COl LUVIUM IN THE WALLULA. FAULT ZONE HOTE:
SKETCH - HEAR WARM SPRIHGS (LOCALLITY C ON FIG.2)
- DECEMBER, 1878 UE 8
C CONTRACT 0 44013 SHANHOH & WILSOH.
IHC.
6EOTECHNICAL CONSULTAHTS
- PORTLAND, OREOOH
0 500 1000 APPROXIMATE SCALE IN FEET AERIAL PHOTOGRAPH NO.
WRH 1-7.
DATED.3-20-69, ARROWS SHOW TRACE OF TOPOGRAPHIC LINEAMENT (GROUND-SURFACE RUPTURE OF BINGHAM AND OTHERS, 1979)
WASHIHGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT NOS.
1
& 4 AERIAL PHOTOGRAPH
- DECEMBER, 1979 UE &
C CONTRACT AE 44D13 SHANNON & WILSON, IHC.
GEOTECNNICAL CONSULTANTS FIG. 5
- PORTLANO, OREGON
I
/~.
119 gJ r
- ('t-(IC (r'"
'1
~~@
Hlchlandjrrl Kannaai'caa' IUHPOFF IOE AHTICLIHE
~Fr
~5
(
WALLULA FAULT
/gg
~,'Warm anrlngakK y'
Walla Walla ~ -~
II 8/p Il WggLA HAILS WALLULAV
+. r".... "i. "CLI
+,,
GAP FAULT 4
. %ALA "A"LA
'L Hilton Freewateb
~ CzOgWW LEGEND
~ ANTICLINE SHONIHG OIGECTIOII OF PLUIIGE
~
SYHCLINE
~~
~ ~ OBLIQUE SLIP FAULTS; ARROWS SHOW DIRECTION OF MOTIOH; BALL ON DOWHTHROWH SIDE; DOTTED WHERE COHCEALED THRUST FAULT
~UG CEO OF C~ILTIjIL HEWCOMB (1965, 1970)'ASHINGTOH PUBLIC POWER SUPPLY SYSTEM (1977 a,b and e)
SWAHSON AND OTHERS (1977)
SHANNON 8 WILSON, IHC.(1979)
. I:500,000 10 20 Hermiston Pendleton SCALE IH MILES WASHINGTON PUBLIC POWER SUPPLY SYSTEM HUCLEAR PROJECT HOS.
1 S
4 REGIONAL STRUCTURAL MAP
- DECEMBER, 1979 UE I C
CONTRACT f 44013 SHANHOH S
- WILSOH, IHC.
GEOTECHNICAL CONSULTANTS PORTLANO.
FIG. 6
C
GEOLOGIC EVALUATIONOF SELECTED FAULTS AND LINEAMENTS PASCO AND WALLA WALLA BASINS - WASHINGTON prepared for WASHINGTON PUBLIC POWER SUPPLY SYSTEM under the direction of UNITED ENGINEERS & CONSTRUCTORS, INC.
Contract No. 440%3, C.O. 43 Task-3
- May,
$ 980 by SALEEM M. FAROOQUI RICHARD E. THOMS SHANNON & WILSON~ INC.
2255 S.W. Canyon Road Portland, Oregon 97201
f.
l
~
R.
TABLE OF CONTENTS Page INTRODUCTION 1.1
SUMMARY
AND CONCLUSIONS 1.2 PURPOSE AND SCOPE 1.3 METHODS OF INVESTIGATION 1.4 ACKNOWLEDGEMENTS FINLEY QUARRY FAULT 2 ~ 1 GENERAL
- 2. 2 DESCRIPTION OF LITHOLOGIC UNITS
- 2. 3 FAULTING 2.3.1 Description of Faulting 2.3.2 Age 'of Faulting 6
KENNEWICK-COLD CREEK LINEAMENT 3.1 GENERAL 3.2 ANALYSIS 3.2.1 Southern Segment (Kennewick Lineament) 3.2.2 Central Segment (Horn Rapids Lineament)
- 3. 2. 3 Northern Segment (Cold Creek Lineament)
- 3. 3 INTERPRETATION 10 12 BUROKER FAULT 4.1 GENERAL
4.2 DESCRIPTION
OF FAULT 16 16 16 GAME FARM HILL FAULT 18 SILVER DOLLAR FAULT 19 BADGER MOUNTAIN FAULT 21
TABLE OF CONTENTS (continued)
- Page 8.
BADGER CANYON FAULT 23 9.
REFERENCES 24 LIST OF FIGURES Figure Number 10 12 Index and Location Map Geologic Sketch of Finley Quarry Fault Photographs of South Fault Photographs of North Fault Photographs of North Fault Photographs of Colluvium Lineament Map Geologic Map Kennewick-Cold Creek lineament area Geologic Cross-Sections Location Map Buroker Fault Geologic Sketch of Buroker Fault Photographs of Buroker Fault
l.
INTRODUCTION 1.1
SUMMARY
AND CONCLUSIONS Seven selected geologic features in the Pasco and Walla Walla.
basins ih Washington State were geologically examined.
The feature's include:
- 1) Finley Quarry fault, 2) Kennewick-Cold Creek lineament,
- 3) Buroker fault>
4)
Game Farm Hill,fault, 5) Silver Dollar fault, 6) Badger Mountain fault>
and 7) Badger Canyon fault.
The field studies consisted of reconnaissance mapping by traverses,,and detailed'apping of a quarry face in the Finley
~
Quarry.
The Finley Quarry fault consists of a 35-foot wide fault-breccia zone.
The fault zone strikes approximately east-west and juxtaposes an I
older colluvial unit against the fault breccia zone along a high-angle reverse fault contact.
The overlying younger colluvial and loess'units are not displ'aced by the faulting.
The age of 'latest movement is estimated to be late Pleistocene.
The Kennewick-Cold Creek lineament is a prominent linear feature that can be seen on topographic maps> aerial photographs and imagery.
,The lineament consists of three distinct'egments, each with,its own peculiar Fgeomorphic, geologic and geographic limits.
The southern segment can be traced as a linear feature along breaks in slope on terrace T
and merging terraces T'nd T.
The central segment consists of an alignment of 6 low 3
4 hills underlain by the Saddle Mountains Basalt.
The northern segment trends along the valley of Co'ld Creek.
No surficial evidence could be found for either hor'izontal or vertical movement along the Kennewick-Cold Creek lineament.
The lineament appears to be of non-tectonic origin.
The Buroker fault is a north-striking reverse fault that juxta-poses Wanapum Basalt against, the Palouse Formation.
The fault appears to splay into several fractures-that traverse the Palouse Formation.
The minimum age of faulting appears to be pre-Holocene.
Our reconnaissance of the Game Farm Hill fault revealed that the basis for identification of the fault is speculative, and that the fault does not exist.
~ The Silver Dollar fault appears to be a scissor fault with a hinge to the east and south-side-down.
II II II g
~
The Badger Mountain fault appears to be restricted to the SE-Hill and does not traverse the entire length of Badger Mountain as mapped by Rockwell.
The existence of the Badger Canyon fault is speculative and the mapping of landslide is incorrect.
1.2 PURPOSE AND SCOPE This report presents the results of geologic studies of selected structures in the Pasco and Walla Walla Basin areas in Washington.
The studies were conducted to evaluate certain fault features mapped by Rockwell and its consultants>
and not previously shown on maps in Amendment 23 (WPPSS>
1977a),
and to evaluate the Kennewick-Cold Creek lineament described by Glass (WPPSS, 1977b).
The structural features selected for field evaluation included:
- 1) Finley Quarry fault,
- 2) Kennewick-Cold Creek lineament, 3)
Buroker fault, 4)
Game Farm Hill fault, 5) Silver Dollar fault, 6) Badger Mountain fault, and 7) Badger Canyon fault, as shown on Figure l.
Except for the Kennewick-Cold Creek lineament (WPPSS, 1977a), all of these structures are based 'on mapping done for the following geologic reports prepared for or by Rockwell Hanford Operations.
Geologic studies of the Columbia Plateau, A Status Report:
Rockwell (1979)
No.
RHO-BWI-55-4 Geology of the southwestern Pasco Basin:
Bond and others (1978)
No.
RHO-BWI-25 Rockwell Annual Report-Fiscal'ear
- 1979, No.
RHO-BWI-79-100 Geology of the Gable Mountain-Gable Butte area:
Fecht (1978),
No.
RHO-BWI-LD-5 Geology of the Nine Canyon map area:
Jones and Landon (1978),
No.
RHO-BWI-IZ)-6 Geology of the Saddle Mountains between Sentinel Gap and 119 3'ongitude:
Reidel (1978),
No.
RHO-BWI-LD-4 Field checking began on January 29 and recessed twice
. from February 2 to February 10,and again from February 13 to March 27, 1980 owing to heavy accumulations of snow and to freezing rains.
Il I
I
The objectives of the field studies were to provide information on:
- 1) quality of exposure;
- 2) existence of faulting in the bedrock and/or surficial units;
- 3) stratigraphic units involved in the faulting; and 4) probable age of faulting.
1.3 METHODS OF INVESTIGATION The field studies consisted of reconnaissance mapping by traverses along the mapped faults, collection of basalt samples for chemical analyses from outcrops critical to understanding basalt stratigraphy and structure; a review of pertinent published information; and dis'cussions with Rockwell geologists who mapped the structures.
The results of the reconnaissance mapping were plotted on U.S.G.S.
7.5-minute series topographic base maps.
Aerial photographs and high altitude imageries were also examined to provide regional information on the Kennewick-Cold Creek lineament.
The cut-slopes of Finley Quarry were examined in detail to provide a complete study'f the exposed geologic conditions.
Detailed mapping of the eastern face included examination> description, and-tracing, of strati-graphic and lithologic units; and a detailed study of geologic structures.
Measurements were made by a tape survey from an arbitrary horizontal and vertical control.
The geologic observations were recorded on a,grid base with a vertical and horizontal scale of 1 inch equals 5 feet.
A geologic sketch of the face was then constructed from these data.
1 ~ 4 ACKNOWLEDGEMENTS Field work for this project was conducted by Saleem M. Farooqui and R.E.
Thorns.
H.H. Waldron and R.J.
Deacon assisted in the preparation of the report.
The report was reviewed by D.D. Tillson.
Il Il Il I
II
2.
FINLEY QUARRY FAULT 2.'1 GENERAL Finley Quarry is located at the west end of The Butte, a,narrow, ridge in sec.
3, T7N, R30E, approximately 2.5 miles south of the town of Finley and 7 miles southeast of Kennewick (Figure 1)..
The quarry is periodi- -'
cally used for production of crushed rock products.
The Butte is a doubly-plunging, anticlinal ri.dge that is underlain by the Saddle Mountains'Basalt,(WPPSS, 1977a; Jones and Landon, 1978);
The anticline is slightly sinous, generally trends eastward, and is mantled by colluvium and loess.
The quarry operation, near the west end of the plunging fold, has exposed a complex fault zone in the east face of the quarry.
This fault zone is referred to in.this report's the Finley Quarry fault.
Geologic conditions at the Finley -Quarry are shown on Figure 2> and photographs of the'ault are shown in Figures 3 through 6.
A description of the lithologic units and structural conditions exposed in Finley Quarry is presented in the following sections.
2.2 DESCRIPTION
OF LITHOLOGIC UNITS The lithologic units and structures exposed in the east face of the quarry are shown in, Figure 2.
- The lithologic units, from youngest to
- oldest, include.loess (Unit 1), colluvium (Unit 2),.fault-breccia zone (Unit 3), and Umatilla Basalt (Unit 4).
The various units'shown on Figure 2
are described below.
Unit 1.
,Loess Light brown sandy. silt; grades upward into darker brown soil
- horizon, and contains scattered, angular basalt fragments ranging in size from 1 to 6 inches diameter.
Thickness ranges from 0 to 10 feet, with overlying soil horizon as thick as 1 foot.
Unit 2.
. 2a.
Colluvium Young Colluvium.
Angular, subangular, and subrounded pebble;to boulder-sized basalt and exotic rock types, in.light brown, sandy silt,
'matrix.
Clasts range in size from 1 to 12 inches.
Exotic fraction. includes quartzites and granites.
Thickness 4
ranges from 0 to 3 feet.
2b.
Old Colluvium.
Similar to young colluvium of 2a, but lacks exotic clasts, and contains interfingering, wedge-shaped lenses as long as 4 feet and as thick as 5 inches composed of subangular and angular pebbles and cobbles to coarse and fine sand.
Sandy silt matrix is light to dark brown, with limonitic staining in places.
Total thickness is unknown, but approximately 5 feet is exposed.
Unit 3.
3a.
Fault-Breccia Zone Clay Gouge.
Varies from dark gray, brittle, slickensided, and 2 to 10 inches in thickness near fault, to greenish-yellow, very finely granular, plastic, with residual basalt fragments away from fault.
These gouge types are separated by a clastic dike of very light terracotta-colored silt, about 1 to 4 inches thick.
Short, discontinuous caliche stringers occur in the greenish-yellow gouge.
Width is approximately 4 feet.
Polished surfaces lack stri-ations.
3b.
Brecciated Basalt.
Vesicular, cobble-sized>
subangular fragments in a yellowish-stained> pulverized, fine-grained basaltic matrix.
Clasts
\\
range in size from about 1 to 10 inches.
Width 4 to 8 feet.
Probably Pomona Basalt.
3c.
Tuff.
Fine-grained,
- cemented, somewhat platy, light buff to white tuff.
Possibly Selah member.
Width 0 to 4 feet.
3d.
Brecciated Basalt.
Angular basalt blocks in a light yellow-brown, finely-crushed basaltic matrix.
Fragments range in size from 1 to 12 inches.
Width 0 to 12 inches.
Probably Pomona Basalt.
3e.
Clay Gouge.
Brittle, slickensided, platy> dark gray to olive-drab, with scattered angular basalt clasts up to 1 foot diameter.
Clastic dikes of coarse to fine sand adjacent to Unit-3f.
Width 0 to 4 feet.
Slickensides lack striations.
3f.
Brecciated Basalt.
Angular, dark brown, pebble-sized basalt in a well-cemented, very light brown ground basalt matrix, with thin clastic dikes of sand.
Width 0 to 3 feet.
Umatilla Basalt.
Unit 4.
Umatilla Basalt Fine grained, glassy, blocky-jointed black basalt with scattered, inclined and vertical yellow-brown shear zones.
2 to 12 inches wide.
Vertical shear zones strike 0
approximately N60 W.
2.3 FAULTING 2 ~ 3.1 Description of Faulting As shown on Figure 2, the Finley Quarry fault consists of a 35-foot wide fault-breccia
- zone, which includes tectonically fragmented and pulverized slivers of the Pomona
(?)
and Umatilla Basalts and the interbedded Selah Member (Units 3a, 3b, 3c, 3d, 3e, 3f and 3g).
A lithologic description of the fault-breccia was presented in Section 2.2.
The fault-breccia zone is bounded by fault planes on the south and north. 'hese 2 fault planes
'are called the south fault and the north fault, and are described as follows:
The south fault (Figure
- 3) strikes N65 W and dips ve'rtically.
0 It separates Umatilla Basalt (Unit "4) from the fault-breccia zone (Unit 3).
Although polished surfaces are present
- along, the fault pla'ne, no striations were observed.,
This fault is overlain by a thin veneer of loess (Unit 1) showing no evidence of a displacement.
The north fault (Figures 4
6 5) strikes approximately east-west and dips 55 degrees to the south. It juxtaposes an older colluvial unit (2b) against the breccia zone.
The older colluvium (Unit 2b) consists of angular basalt frag-ments in a sandy and silty matrix (Figure 6) with brown and red-brown iron-staining present throughout.
Horizon-tally bedded, fluvial sand lenses interfinger with the older colluvium.
We estimate the minimum probable age of this colluvial unit (2b) is Wisconsin.'he adjoining fault-breccia zone (Unit 3) consists of sheared, 'pulverized Pomona
('?)
and Umatilla Basalts.
Numerous slickensides are present in the clayey gouge zones, but no striations
.,were observed.
Generally, these slickensides are sub-parallel to the fault plane..
2.3.2 Age of Faulting The Finley Quarry fault zone, and specifically the north fault, is overlain by a thin (0 to 2 feet) younger colluvial unit (2a), which in turn is overlain by 0 to 10 feet of loess (Unit 1).
The overlying younger colluvial unit (2a) is not displaced by the north fault; however>
some fractures emanating from'he fault (Figure 5) seem to dissipate into this unit.
The overlying loess also is apparently unaffected by faulting.
The age of this loess is estimated to be approximately 7,000 yea'rs B.P.
This estimate is based on the presence of what is probably Mazama ash within similar loess on slopes in nearby areas.
The Finley Quarry fault lies along the projected trend of the Wallula fault (WPPSS>
1977a; Shannon 6 Wilson, 1979).
Latest movement of the Finley Quarry fault is estimated to be late Pleistocene (pre-7000 years).
3.
KENNEWICK-COLD CREEK LINEAMENT
\\
Wt 3.1 GENERAL
. The Kennewick-Cold Creek lineament is a prominent linear feature paralleling the Rattlesnake Hills-Wallula lineament from the vicinity of Wallula Gap to near the east end of Yakima Ridge, a distance of about 20 miles (Figures 1 s 7).
The term "lineament" as applied to this feature follows the usage of O'eary and others (1976). It can be seen on AMS and U-S.G.S.
7.5-and 15-minute topographic maps; on both vertical and oblique low altitude aerial photographs, on LANDSAT imagery; and'n various geologic maps.
Relative resolutions of these imageries are shown on the Lineament.
Map (Figure 7).
The broad, finely-dotted pattern represents the lineament as it appears on'he LANDSAT photographs.
The narrower, more coarsely-dotted.
strips show the three major segments of the lineament on the AMS sheet.
Topographic breaks, readily seen in the field and on 7.5-and 15-minute topo-,
graphic maps and low-altitude aerial photographs are indicated by broad solid lines (dashed where" less distinct).
The "Kennewick-Cold Creek Lineament" was recognized and described'y Glass (WPPSS, 1977b) as follows:
"The Kennewick lineament parallels the Rattlesnake structure from Wallula Gap to approximately Kennewick.
The lineament is characterized by an abrupt vegetation contrast and an east-facing break in slope (Figure K-15)
~
A number of factors have led me to interpret this feature as a terrace.
At its northern, end the Kennewick lineament turns to the northeast and joins several similar features originating to the west and northwest.
At its southern end the lineament gradually (sic) decreases in height and cannot be followed south of Finley.
Several older terraces appear upslope to the west of the Kennewick lineament and trend roughly parallel to it.
. The Cold Creek lineament extends from Columbia Camp to beyond, Benson Ranch (Figure K-24, Sheet 2).
The lineament is eminently detectable on LANDSAT imagery and 'parallels the Rattlesnake structure."
In an earlier report, Glass (1977) described the lineament as paralleling the Rattlesnake trend, but about 2.5 kilometers east of it, and as being formed by a 2 to 3 meter-high topographic break combined with a striking contrast in vegetation.
He also noted several ponds resembling sag ponds along the lineament's trend and suggested the lineament may extend onto the Hanford reservation in the vicinity of Cold Creek.
Although the lineament may~appear to 'be a single, continuous
~
feature on high-altitude imagery or on larger-scale topographic
- maps, our detailed analysis shows that it actually consists of three distinct segments, each with its own peculiar geomorphic, geologic and geographic limits.
In addition, these segments display angular alignments of features that can differ from each other by as much as 25 of azimuth, although they are.usually 0
nearly coincident.
The. Geologic Map (Figure 8) and the Geologic Cross-sections (Figure 9) show the details of the topography and geology in the vicinity of the lineament.
Geology and geomorphology of the area are based upon this investigation and previous mapping by WPPSS (1977a) and Rockwell (1979a).
Observations of the physical nature of the'three lineament structures are presented in Section 3.2, and the interpretations are given in Section 3.3.
3.2 ANALYSIS 3.2.1 Southern Segment (Kennewick Lineament)
This segment is a distinct feature on topographic maps from scales of 1:24,000 down to 1:250,000.
It can be seen plainly as a slope break and vegetative change on both vertical and oblique aerial photographs
.(see
- WPPSS, t
1977b, Figures 2R K-12 and 2R K-15) as well as on LMDSAT photos of the area:
It is a portion of a broader pattern of terraces first described by Farooqui
,(WPPSS, 1977a> p.
2R H.5-10), who stated:
N "Four Quaternary terraces are mapped along the south margin of the Pasco Basin.
These terraces occur at approximately 340 foot elevation (T ),
370 foot 1
elevation (T ),
500 foot elevation (T ), and 600 foot elevation (T4).
The two lower terraces, T1 and T, are developed on younger glaciofluvial deposits.
The higher terrace>
T is overlain by 4
Touchet beds.
Northwest of M-Hill, this terrace T
is developed on the Ringold Formation.
Locally Kennewick fanglomerate may underlie the terrace southeast of M-Hill."
On the ground, the lineament can be traced as a linear feature, 0
trending about N50 W, from Piert Road on the southeast to Carlson Road on the northwest, a distance of about 3.5 miles.
Throughout its entire trend, it consists of a northeast-facing break in slope on terrace T3.
From Carlson Road on to the northwest as far as south Garfield Street, a distance 'of about 2.5 miles, it continues as a linear feature but consists of the north-east-facing break in slope of two merging terraces, T
and T4.
Thus, the 3
total distance over which a distinct linear feature can be traced is about 6 miles.
Beyond the southeastern end, the contours along this trend continue parallel to it as far as the Columbia River, but no distinct break in slope can be detected.
Along the Heals-Yellepit -Road, between Toothaker Road and Goose
- Gap, a series of low, parallel ridges are crossed,, but these do not involve sufficient elevation changes to produce any effect at a scale of 1:24>000.
Beyond south Garfield Street to the northwest, the lineament is lost in the dissected alluvial fan at the mouth of Zintel Canyon.
Flat surfaces with elevations equivalent to those of terrace T
can be seen about 3
1 mile to the northeast of the lineament, and which are centered on the low hills where Triangulation Point "Junk" is located (Figures 7 6 8; Figure 9, sections C-C'; and D-D').
Terrace T is underlain mainly by gravel and minor sand and silt layers, but little distinct bedding can be seen.
The gravel is composed of basaltic and exotic-(plutonic and metamorphic) rock types, which are rounded to subangular and range in size from pebbles to boulders.
Weathering rinds on basalt -clasts average about 1/8".
No significant change in lithology could be seen throughout the entire break in slope, nor between terraces T
and T, which have similar clast rock types.
3.2.2 Central Segment (Horn Rapids Lineament)
Topographically, this portion of the lineament consists of a series of 6 low hills about 600 to 700 feet in elevation, which trend about 0
N35 W along the southwest side of the Yakima River from Leslie Road on the southeast to just north of Horn Rapids on the northwest (Figures 7 6 8; Figure 9, sections Bl-Bl and B -B2).
Attention was initially drawn to this feature, described as the "Horn Rapids Alignment" > by Jones and Deacon (1966).
Later (WPPSS,.1974),,
it was discussed in moxe detail:
"Horn Rapids Alignment - The Horn Rapids alignment consists of a series of 6 small elongated domes, exhibiting a very low relief of 50 feet to a maximum of 350 feet.
Most of j'he relief occurs on the northeast sides and gentle slopes are common toward the southwest.
The hills extend for a distance of about 13 miles in a southeastward cirvilinear (sic) path from approximately 'one mile north of Horn Rapids on the Yakima River to about two miles south of Richland (Figure 2.5-4 and Appendix 2D).
The maximum amount of surface structural relief occurs on the hill adjacent to the town of West Richland.
This hill exhibits about 350 feet of relief above,glaciofluvial sediment.
Folding of the dome is relatively gentle, with maximum mapped dips of basalt flows being about 35 degrees."
The hills consist of nearly flat-lying flows of the Elephant Mountain and Ice Harbor Members of the Saddle Mountains Basalt mantled by glaciofluvial deposits.'n one place'long the lineament, in the banks of the Yakima River (NE 1/4 sec.
16, T9N, R28E)> flat-lying beds of the Ringold Formation are at the same elevation as an outcrop of the Ice Harbor flow at the southern end of the exposure.
A covered interval separates the two units, obscuring their contact relationship.
Structure along this trend appears to be very minimal, with shallow dips of 2 to 5 on gentle anti-0 clinal folds (Rockwell, 1979a).
3.2.3 Northern Segment (Cold Creek Lineament)
This segment, prominent on aerial photographs and topographic maps of all scales, consists of the N50 W trending valley of Cold Creek, 0
which runs perpendicular to the northeast,-facing pediment, of the Rattlesnake Hills., On the ground, the only distinctive portion of the northern segment is a-low n'ortheast-facing
- scarp, about 50 feet in height, which borders
Cold Creek to the southwest from its confluence with the Yakima River to a point about 2.5 miles upstream.
This scarp; trending about N25 W, is visible 0
on Bonneville Power Administration (BPA) aerial photograph PSLG7E-43 and on the Richland 15-minute topographic map (Figures 7 6 8; Figure 9, section A-A').
Units exposed in the scarp include the lower of the two Elephant Mountain flows overlain by colluvium and glaciofluvial deposits, and valley fills of coarse, poorly sorted, angular. material apparently derived from Rattlesnake Hills.
Tpe northeast bank of Cold Creek is composed of glacio-'luvial deposits, chiefly gravel and sand.
The pediment was constructed on gently eastward-dipping basalts (WppSS, 1977a)>
capped with a thin veneer of colluvium, now being dissected by streams downcutting through valley fills.
The scarp cuts across both the basalt and the old valley fill.
3.3 INTERPRETATION The southern
- segment, (Kennewick lineament),
which chiefly consists of the break in slope between terrace levels T
and T, was probably produced as an erosional feature during one of the later episodes of Spokane flooding (Wisconsin age).
This is supported by the existance of similar gravel at similar elevations immediately across terrace T
to the northeast of this 2
trend (see section C-C'n Figure 9).
The linear nature of the feature, although long and distinct, is not unique among erosional or depositional features produced by Spokane flooding.
Between Umatilla and Boardman Junction in Oregon, a 400'-terrace can be traced as a near-straightline feature for about ll miles; while in the Portland area,,a 200'-terrace can be traced for about 6 miles.
Thus> it appears that-the Kennewick lineament may represent a streamlined erosional feature produced by flood waters rushing toward Wallula Gap.
The dramatic vegetational change along 'the lineament coincides with the proximity of groundwater to the surface.
In fact, the ponding of spring water issuing from the gravel near the base of the break in slope between terrace T
and T was noted by Glass (WPPSS, 1977b),
who originally thought they might be sag ponds.
Ponding appears to be caused, in part> by the impervious lining of the irrigation ditch, which parallels the break in slope.
The possibility of right-lateral motion along this trend was hypothe-sized and then discarded by GLASS (WPPSS, 1977b, p.
2R K-10 and -11):
"However, between Terril Road and 27th Avenue (Figure K-24, Sheet
- 1) the stream channels across the Kennewick lineament appear too large to have been generated by the streams which currently feed them.
The major streams from the highlands to the west are located at the ends of the domes on the Rattlesnake structure.
These streams are currently cutting relatively deep channels across the Kennewick lineament.
A possible interpretation of these apparently anomalous channels is that movement along the Kennewick lineament has progressively displaced the channels on the right-lateral direction.
This would result in a total offset of 3,000 meters.
Offsets of this magnitude,
- however, seems incredible for a feature which can only be traced for approximately 16 kilometers.
The most reasonable interpretation is that the Kennewick lineament is an old terrace of the Columbia River."
It should be further noted that only two major streams, which exhibit the appropriate pattern, occur within the southern
- segment, while at the very northern end of the segment, Zintel Canyon exhibits exactly the opposite direction in its passage around the northern end of Pipeline Hill.-
In addition, Faroogui (WPPSS, 1977a, p.'R'H.5-10) commented on the lack of evidence 'for deformation:
"Allof the terraces appear to be free of deformation and show no evidence of tectonic movement."
According to the interpretation given above, the Kennewick lineament would have been produced in late Wisconsin time.
Alluvial fans produced since that time, by sidestreams debouching onto terrace T, show no features that can be considered part of the alignment.
The central segment (Horn Rapids lineament),
consisting of a series of low basaltic hills mantled by glaciofluvial deposits, is tenuously interpreted as a series of very low amplitude folds parallel to and probably produced simultaneously with the Rattlesnake Hills-Wallula lineament (Figure 9, sections B -B'nd B -B').
These were apparently later modified into erosional scabland remnants by the plucking action of Spokane flood waters and subsequently nearly buried under glaciofluvial deposits.
No evidence
for faulting was observed.
This agrees with the interpretation Originally expressed by Fugro, Inc.
(WPPSS, 1974):
"No faults were identified along the Horn Rapids alignment during the detailed mapping done for this investigation.
Photogeologic lineations appear to be related to differ-ential erosion along basalt joints and commonly are parallel to joint sets measured in the field.
Breccia zones observed at isolated localities are identified as flow breccia based on the scoriaceous and vesicular nature of the basalt.
It is concluded that the Horn Rapids alignment is not faulted.
Blume and Associates (Reference
- 50) arrived at the same conclusion during mapping for the FFTF study."
Erosion by the Yakima River in post-Wisconsin time has enhanced these features.
P The northern segment (Cold Creek lineament) consists of two features related to the action of Cold Creek.
The first of these is the alignment of the valley of Cold Creek.
This is not surprising, as it runs counter to the slope of the Rattlesnake Hills pediment, exactly as it should.
Such situations are the rule in the arid cycle of erosion.
The second feature is the low scarp, seen along the west side',of the valley near the confluence with the Yakima River (Figure 9, section A-A').
This was probably produced by the lateral planation of Cold Creek.
Concerning this portion of the lineament, Glass (WPPSS,- 1977b, p.
2R K-10 and -ll) has commented:
"Interpretation of low sun-angle photography has failed to yield a conclusive interpretation."
Both of these features are probably post-Wisconsin in age.
In conclusion, no surficial evidence could be found for either horizontal or vertical movement along the Kennewick-Cold Creek lineament.
The existence of the same stratigraphic horizons at the same elevations across the lineament precludes any significant vertical movement.
These realtionships can be seen along the Kennewick lineament where the gravel of terrace T3 occurs on both sides of the lineament.
Again, along the Cold Creek lineament, the lower Elephant Mountain flow crops out at approximately
the same elevation on both sides.
Along the Horn Rapids, lineament, the upper lacustrine and conglomerate members of the Ringold Formation crop out on the southwest side of the feature (Figure 9, section B2-B'), while the blue-clay member has been recorded from a well at the Richland Wye, at a depth of 72 feet, on the northeast side of the lineament (Newcomb, 1958).
Thus, the stratigraphic progression toward the northeast across the lineament is in the normal sense, with no indication of reversal.
4.
BUROKER FAULT 4.1 GENERAL The Buroker fault is exposed, in a road cut along Russell Creek, Road, approximately 6 miles east of Walla Walla in sec.
31, T7N, R37E.
The location of the exposure is shown on Figures 1 and 10.
A sketch of the fault exposure is shown on Figur'e ll and photographs of it are shown: on Figure 12.
The Buroker fault investigation was conducted to evaluate its reported late Cenozoic, (post-Columbia River Basalt) movement.
The fault was described in,Rockwell (1979a),
although it was not shown on the map accompany-ing the text.
The Rockwell description is as follows:
"Reconnaissance mapping of sediments within the Blue Mountains subprovince showed the presence of two minor faults which cross-cut late Cenozoic sediments (Plate XX-16).
One of these faults is a small reverse fault in a roadcut southeast of Walla':Walla on the Buroker quadrangle (T7N, R37E).
The fault appears to cut overlying fluvial gravels and.an older loess, but does not deform overlying younger loess, The age of these.,sedimentary units currently is not known;
- hence,
.age limits for the structure are not yet established.
A second nearby fault, cutting the basalt Frenchman S rin s Member is robab t
(
P g
)>
p ly rela ed to the previously described structure."
Swanson and others (in Rockwell; 1977a",
b) mapped a small northeast-striking fault in the vicinity of the Buroker fault.
However>
from their mapping> it is not clear whether they mapped the Buroker fault>
as described in Rockwell (1979a), or some other fault.
'I 4;2 DESCRXPTION OF FAULT The Buroker fault is exposed in a road cut excavated at the south end of a north-northeast-trending ridge.
The cutface is oriented east-west and is approximately 20 feet high near the middle.
As exposed in the cut, the ridge is underlain by -a soil horizon (A-horizon), tan loess, red-brown'oess (Palouse Formation) and basalt
(Figures ll 6 12).
The A-horizon soil zone, which mantles the ridge slopes, is approximately 1 to 2 feet thick and, consists of.dark gray silt'ith abundant organic debris.
The underlying tan loess is 2 to 5,feet thick and is composed of silt, wi;th scattered caliche stringers and nodules.'ccording to Newcomb (1965), this tan loess is derived from the reworking of the Touchet beds';
Most'of the caliche stringers in-this'oess are sub-parallel to the topography.
The tan silt also mantles the slopes.
The Palouse'ormation (Newcomb>
1965) occurs between the basalt and,the tan loess>
and consists of red-brown, clayey silt and some scattered angular to subrounded'asalt fragments.
The contact betw'een the tan loess and the Palouse Formation appears to be gradational and unconformable.
Only a small portion of=basalt is exposed in the cut; most of it is covered by debris.
The limited exposure shows that the basalt consists of highly weathered and altered, greenish-
'ray and red-gray> closely-'jointed basalt of the Dodge flow (Swanson and others, in Rockwell, 1979a).
The contact between the basalt and the Palouse I
Formation is nearly horizontal.
The Buroker fault is a reverse fault that appears to strike. in-a general north-south direction. It dips approximately 26 degrees to the west and is in sharp fault contact with the Palouse Formation (Figures ll 6 12).
The throw is approximately 22 inches.
The fault appears to 'splay, into several fractures that traverse the Palouse Formation 'and vanish in the overlying tan loess.
Some of these fractures are lined with caliche.,
The fault cuts both the Dodge flow of the Wanapum Basalt of middle Miocene age and the Palouse Formation of Pleistocene age.
The Pleistocene age of
'I the Palouse Formation is based on its stratigraphic position, lying above
'he old gravel and beneath the Touchet beds of Pleistocene age (Newcomb,.
1965).
The minimum age'f faulting appears to be pre-tan loess,'r pre'-
Holocene.
~
i 5
S
5.
GAME FARM HILL FAULT Game Farm Hill (Jones and Landon, 1978) or K-Hill (WPPSS, 1977a) is located in section 30, T8N, R30E.
The hill is underlain mainly by Pomona'nd Umatilla Basalts.
A-small section of the Priest Rapids Basalt crops out above a creek bed along the south slope of the hill.
The hill is a doubly-plunging anticline, defined by the distribution of the Pomona Basalt.
A small outcrop of the Umatilla Basalt occurs near the structural culmination (WPPSS, 1977a; Jones and Landon, 1978; Rockwell> 1979a)..
Jones and Landon (1978) mapped an approximately 1/2-mile long fault (Game Farm Hill fault) along the south flank of the anticline.
A field check was conducted to evaluate the existence of the'fault, because it lies along the trend of the Rattlesnake Hills-Wallula lineament (WPPSS, 1977a and 1974; Rockwell> 1979a).
This minor fault, as shown on the map (Rockwell, 1979a), is within the Umatilla Basalt.
Two deep ravines, which cut the inferred fault trend show no evidence of faulting, although some minor shears and altered basalt were observed.
Such minor shears,
- however, are common in tight folds of the Columbia Plateau.
Our reconnaissance of the faulting revealed that the basis for identification of the fault is speculative 'and lacks direct field evidence.
The ravines cutting across the trend show unfaulted basalt and rule out the interpretation of faulting.
Therefore, in our opinion, a fault: as shown on the Rockwell Map (1979a) does not exist.
6.
SILVER DOLLAR FAULT The Silver Dollar fault was originally mapped by Rockwell (1979a) in secs.
1, 2 and 3, T12N,
- R23E, and secs.
6 and 7, T12N, R24E (Figure 1) along the east flank of the east-plunging Yakima Ridge anticline.
As shown on sheet 4 of Rockwell's (1979a) map, the fault offsets the Frenchman
- Springs, Roza and Priest Rapids Members of the Wanapum Basalt against the Umatilla and Pomona Members of the Saddle Mountains Basalt in secs.
1, 2 and 3,
- T12N, R23E, and is mapped solely within the Pomona Member in section 7,
- T12N, R23E.
The total indicated length of the fault is approximately 5
miles.
The eastern one-third of the fault is shown partly in bedrock and partly covered, whereas the western two-thirds of the fault length is shown covered by loess.
The Silver Dollar fault extends westward into the Yakima Bombing Range.
To the east, it is shown branching into two faults in sec.
1,
- T12N, R23E.
The shorter north branch terminates in the Pomona Member; whereas the longer south branch extends for one mile and is shown also terminating in the Pomona Member.
Rockwell (1979a) interprets the fault as either a high angle reverse or a normal fault with the south-side-down.
Our field reconnaissance confirms the presence of the Silver Dollar fault west of the,Yakima-Benton County line.
We found no evidence, however, to confirm either the branching of the fault or its eastward extension into sec.
7, T7N, R23E.
Evidence of faulting observed during this study confirming the Silver Dollar fault is based on the following field observations:
Dark gray to black, glassy to very fine-grained, closely-jointed basalt of the Umatilla Member to the south is in contact with a dark gray to black, columnar, fine-grained aphyric flow of the Frenchman Springs Member to the north.
These members occur at about the same elevation (approxi-mately 1800 feet) in a south-draining ravine between secs.
1 and 2.
However, the members are separated by an approximately 200-foot wide area covered by colluvium, which conceals the nature of the fault contact and breccia zone.
5 I
Northward, the aphyric flow of the Frenchman Springs Member is covered by a sequence of phyric and aphyric flows of the Frenchman Springs Member.
This member, in turn> is overlain by the Roza, Priest Rapids, Umatilla and Pomona Members.
The Umatilla Member occurs at approximately elevation 2200 feet.
Accounting for a slight southward dip off the Yakima Ridge anticline, a 300-foot vertical displacement is estimated on the fault in this ravine.
Based on similar stratigraphic relationships, this estimated 300-foot displacement appears to continue west-ward along the fault.
- Eastward, the displacement appears to decrease rapidly.
Apparently the unfaulted Pomona Member lies along the projected trend of the fault in the SE 1/4 sec.
6.
Our field reconnaissance shows the mapping of the thick Umatilla Member by Rockwell (1979a) in a south-draining ravine in the E 1/2, sec.
1,
- T12N, R23E, south of the fault, appears to be in error.
Within a short distance south of the fault, a 40-foot thick tuff bed is exposed in the ravine.
This tuff bed, not shown on the Rockwell map (1979a), is underlain by gray, fine-to medium-grained, blocky columnar basalt, probably the Priest Rapid Member (7).
~ The Umatilla Member occurs north of the fault, as mapped by Rockwell.
However, there is no evidence that it occurs in the ravine south of the fault as it is shown on the Rockwell map.
Also, an anomolous stratigraphic relationship is indicated in the mapping of the Ellensburg Formation (Tel) by Rockwell (1979a) in sec.
7> T7N, R24E.
To the west, the "Tel" unit is, mapped between the Elephant Mountain and Pomona
- Members, but the continuation of the same bed eastward is mapped within the Pomona Member.
This anomolous relationship may be real or due to stratigraphic and structural mis-mapping.
A'mall fault segment was mapped by WPPSS (1977a) in SW 1/4 sec.
34, T13N, R23E.
This fault lies on trend with the Silver Dollar fault, and is probably a continuation of it.
Based on the stratigarphic displacement
- observed, we interpret the Silver Dollar fault to be a scissor fault with a hinge to the east in the Pomona Basalt (sec.
1, T12N, R23E) and increasing displacement to the west.
The western termination of the fault was not determined.
7.
BADGER MOUNTAIN FAULT Badger Mountain consists of three elongate hills.in T9N, R28E that
, trend northwesterly across the area between Badger Coulee. and the Richland-Prosser Highway.(Figure 1)'.
For this discussion, these hills'are named v SE-Hill, Mid-Hill an'd NW-Hill.
The SE-Hill is located -near the mouth of Badger, Coulee and'W-Hill is located near the highway.
All three hills are, underlain by the Ice Harbor, Elephant Mountain, Pomona and Umatilla Members of the Saddle Mountains'asalt (WPPSS,
- 1974, 1977a; Rockwell, 1979a; Bond I
and others, 1978).
They are commonly overlain by an extensive-loess cover above an elevation of approximately 1000 feet and by undifferentiated loess and Touchet beds below thi.s elevation.
The basalt units crop out generally near the crest of the hills,, while the flanks are mantled by a mixture, of colluvium and silt.,
Structurally, the hills consi.st of three elongate, doubly-plunging, slightly en echelon, sinuous anticlines.
The mapping-of SE-Hill for WPPSS (1977a) showed an overturned fold with a possible fault along the north flank.
The fault interpretation was based on:
- 1) the tight geometry of the, fold; 2)steep to reverse dips f
of the Elephant Mountain and Ice,Harbor'embers along the north flank; and F
3) an escarpment along and near the fold-axis.
The mapping of the Mid-and NW-Hills, which are comparatively broader folds-> did,not show evidence of, faulting similar to that observed in the'SE-Hill (WPPSS, 1977a).
Rockwell (1979a) and Bond and others (1978) mapped a northwest-striking fault along the north flank of all three of the Badger Mountain Hills between Badger Coulee and the highway.
The mapping of the fault along the north flank of the SE-Hill i's in general agreement with'the 'mapping by. WPPSS, (1977a).
However, its northwestward extension'eyond this hill (northwest of sec.
34, T9N, R28E) could'ot be confirmed or substantiated during this reconnaissance.
As mentioned earlier, the mapping of faulting in,the SE-Hill is largely interpretive, based on the tight geometry of the structure, reversed dips, and an escarpment; Our reconnaissance along the fault in the.Mid-and NW-Hill area did not reveal any comparable features that could be attributed to faulting.
Our reconnaissance did confirm previous mapping of the Mid-and NW Hills by WPPSS (1977a).
Both of these hills appear to be rather broad, slightly asymmetrical, doubly-plunging folds.
Although the
area across the trace of the projected fault is covered by colluvium and
- loess, the basalt members do not show any stratigraphic displacement across the postulated fault.
The topographic breaks on the north flank of the Mid--
Hill,,described by= Bond and others (1978) as due to the faulting, appear to be due to stacked and dipping flows.
Moreover, these topographic breaks neither lie on trend nor do they form an escarpment; they lie en echelon and parallel to the ridge, and rise in elevation in an up-dip direction.
Therefore, these breaks are considered non-tectonic in origin.
The Badger Mountain fault> as mapped by Rockwell (1979a) and Bond and others (1978), could not be confirmed in its entiiety during this reconnaissance.
The faulting appears to be confined to the SE-Hill> and the geometry of the plunge suggests the fault dies out rapidly in the fold (WPPSS>
1977a).
8.
BADGER CANYON FAULT The Badger Canyon fault (Rockwell, 1979a; Bond and others, 1978) was mapped across Badger Canyon, south of, Badger Coulee, in sec.
29,
- TSN, R28E (Figure 1).
As shown on sheet 11 of 12 (Rockwell, 1979a),
the one-mile long, northwest-striking fault appears to cut landslide deposits in a right-lateral sense.
Based on our reconnaissance, the area in general, and within a 1/4-mile on either side of the fault in particular,'s covered by loess and colluvium.
,Mapping of 'the Priest Rapids, Umatilla, Pomona and Elephant Mountain Members within 1/2 mile of the fault, therefore, is highly conjectural, because few basalt outcrops occur in this area.
The juxtaposition of the basalt
- members, as shown on the map '(sheet ll, Rockwell, 1979a), is, therefore highly conjectural.
In addition,, our reconnaissance suggests that landsl'ide deposits occur only on the east side of the canyon, not on both sides as shown on sheet ll of 12 (Rockwell, 1979a).
Thus, our reconnaissance indicates the existence of the Badger Canyon fault is highly conjectural, and that the existence of a landslide
'n the west, side of the canyon is incorrect.
9.
REFERENCES Bond, J.G.
and others,
- 1978, Geology of the Southwest Pasco Basin, RHO-BWI-C-25:
prepared by Geoscience Research Consultants for Rockwell Hanford Operations, Richland, Washington.
Fecht>
K. R.> 1978, Geology of Gable Mountain-Gable Butte area; Rockwell Operations, RHO-BWI-LD-5, Richland, Washington.
Glass, C.E.,
1977, Letter report, prepared for Washington Public Power Supply System.
- Jones, F.O.,
and Deacon, R.J
, 1966, Geology and tectonic history of the Hanford area and its relation to the geology and tectonic history of the state of Washington and the active seismic zones of western Washington and western Montana:
report prepared for Douglas United Nuclear, Inc.
- Jones, M.G., and Landon, R.D.,'978, Geology of the Nine Canyon map area:
Rockwell Hanford Operations, RHO-BWI-LD-6, Richalnd, Washington.
Newcomb, R.C.,
1958, Ringold Formation of Pleistocene age in type locality, the White Bluffs, Washington:
Am. Jour. of Sci., Vol. 256,
- p. 328-340.
Newcomb> R.C.,
- 1965, Geology and groundwater resources of the Walla Walla River Basin> Washington-Oregon:
U.S. Geol. Surv. Water Supply Bull. No. 21.
O'eary>
D.W., Friedman, J.D.,
and Pohn, H.A., 1976, Lineament, linear, lineation:
some proposed new standards for old terms:
Geol.
Soc.
Am., Bull., Vol. 87, p.
1463-1469.
Reidel> S.P.,
- 1978, Geology of the Saddle Mountains between Sentinel,Gap and 119 30'ongitude:
Rockwell Hanford Operations, RHO-BWI-LD-4, Richland, Washington.
'\\
Rockwell Hanford Operations,
- 1979a, Geologic studies of the Columbia Plateau:
a status report:
RHO-BWI-ST-4> prepared for U.S. Dept. of Energy.
Rockwell Hanford Operations, 1979b, Basalt Waste Isolation Project Annual Report-Fiscal Year 1979:
RHO-BWI-79-100, prepared for U.S.
Dept. of, Energy.
Shannon 6 Wilson, Inc., 1979, Evaluation of faulting in the Warm Springs Canyon area, southeast Washington:
by Saleem M. Faroogui> report prepared for Washington Public Power Supply System, under direction, of United Engineers 6 Constructors, Inc.
Washington Public Power Supply System (WPPSS),
- 1974, WNP-1/4,PSAR, Amendment A, Appendix 2D, "Geologic mapping of the Rattlesnake-Wallula alignment and associated structures",
by Fugro,'nc.
Washington Public Power Supply System (WPPSS),
- 1977a, WNP-1/4 PSAR, Amendment
~
23, Sub-appendix 2R H; "Geologic evaluations of structures in the Columbia Plateau",
by Shannon and Wilson, Inc.
Washington Public'ower Supply Syst: em (WPPSS),
- 1977b, WNP-'1/4 PSAR, Amendment 23, appendix 2R K> "Remote sensing analysis of the Columbia Plateau",
by Charles E. Glass.
a)
View of the south fault of the Finley quarry fault.
b) Photograph showing the details of the cemented fault breccia (unit 3f)
See Section 2 for descriptions of the lithologic units OVERLAY FIGURE 3
Il
a)
View of the north fault of the Finley quarry fault.
Hammer at the fault contact between colluvium 2b and fault breccia 3a.
b) Detailed view of the north fault.
Angular basalt debris in a light brown sandy silt matrix (unit 2b) in fault contact with green fault gouge.
See Section 2 for description of the lithologic units OVERLAY FIGURE 4
I
View of north fault.
A one-half to 2-inch thick swelled and pinched, brown clastic dike in the gouge.
Fractures emanating from the fault may be seen dissipating into Unit 2a.
t Y
V
~
'elf a)
At-.
4 l7 IPi c
A 5
P A
~ j Kj-
~r
~ p (a) 8 (b) Photographs of colluvium showing the lithologic details.
Photograph (a) is just left of the north fault.
The boulder in this photo may also be seen in Figure 3a.
The mottled brown. colluvium (unit 2b) may be seen lying under light brown colluvium (unit 2a), which also shows some small white quartzite clasts.
- FIG, 6
A 1000 I-500 I-)
- Qgf, Tem
?
~~
P Qal hC UJ IJJ OC CD ID C)
I
? Qg
,Qds A'000 500 C)
O UJ 0
VERTICAL EXAGGERATION X 4 A
~ 2000 hC UJ LIJ CY C5 CDQ A'000 UJ C)I-)
UJ LLI r
0 SEE FIG; 8 FOR LOCATION OF CROSS-SECTION C),
I-0 LEGEND:
Qal Alluvium Qds Stabilized, dune Qg Pasco gravel
- Qgf, Glaciofluvial deposits Tem Elephant Mountain Member deposits Tp Pomona Member 0
2000 4000 HORIZONTAL SCALE IN FEET WASHINGTON PUBLIC POWER SUPPLY. SYSTEM NUCLEAR PROJECT NOS.
1 5 4 GEOLOGIC CROSS-SECTION A-A'HEET 1 OF 5
MAY, 1980 UE 8t, CCONTRACT ¹ 44013 H
N N
8t WILSON, INC.
Geotechnical Consultants Portland Ore on FIG,9
1000 500 I-)
LLI LJJ B1 Qgf CO C) 0-Ti Qgf I
Qal B.1' 1000 500' I
UJ 0
0 VERTICAL EXAGGERATION X 4
~ 2000 C)
I-0 B1 CO C)
OC IJJ O'C I
I B1'000. ~
. C)
I 0
SEE FIG.
8 FOR LOCATION OF CROSS-SECTION LEGEND:
Qal Alluvium Qgf Glaciofluvial deposits Ti Ice Harbor Member Tem'lephant Mountain Member deposits 0
2000 4000 HORIZONTAL SCALE IN FEET WASHINGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT NOS.
1 8t 4 MAY, 1980 GEOLOG C CROSS-SECTION B1 B
SHEET 2 OF 5 UE
& C CONTRACT ¹ 44013 Geotechnical Consultants
- Portland, Ore on FIG,9
B2 1000 cCV LU M
B2'000, 500 I-8 l
Qgf
- Ql Qg(T)
QTr Ti 500 EDI-)
LIJ VERTICAL'XAGGERATION X 4
~ 2000 CD 0
B2 Zo )
M IX 5
I B '
2000 ~.
CDI-M LIJ LEGEND:
SEE FIG.
8 FOR LOCATION OF CROSS-SECTION Qg(T,)
Qgf QTr Tl Pasco gravel, Terrace 2
Glaciofluvial deposits Ringold Formation Ice Harbor Member 0
2000 4000 HORIZONTAL SCALE IN FEET WASHINGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT NOS.
1 5 4 MAY, 1980 GEOLOGIC CROSS-SECTION B2-B2'HEET 3 OF 5 UE 5 C CONTRACT.¹ 44013 Geotechnical Consultants
- Portland, Ore on FIG.9
C 1500 LLI
)
C'500 1000 ~
LEGEND:
Qt Touchet beds Qg Pasco gravel Qf Alluvial fan deposi-ts
( TI, T2, T3 T4 )
Terraces devel oped on Qt and Qg Tp Pomona Member CD'l-500 TP Qt(T4)
Qg(T,)
Qf
) Qg(T,)
Qg C)
>I-500 VERTICAL EXAGGERATION X 4 C
~ 2000 C'000 ~
0 2000 4000 HORIZONTAL SCALE IN FEET C) 0 SEE FIG. 8 FOR LOCATION OF CROSS-SECTION 0
WASHINGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT NOS.
1 5 4 GEOLOGIC CROSS-SECTION C-C'AY, 1980 SHEET 4 of 5 UE 8
C CONTRACT 8 44013 Geotechnical Consultants Portland Ore on FIG.9
R SI R R 55 R W R R R R IR R R R R R R
1000 500 I-)
D Tp Qt(T4)
Qg(T3)
O cL:
c(O CO CY hC O
W Qg(l 2)
C),
cL;,'
O O Qg(T
)
j D'.
1000 500 OI-VERTICAL EXAGGERATION X 4 D
~ 2000 O
I) 0 C)
O 6C IJJ LI cL:
a O
P CL W
O II I
SEE FIG.
8 FOR LOCATION OF CROSS-SECTION C)cf O O
cC aC O O
O D',
2000 ~
OI-0 'IJ IJJ LEGEND:
Qt Touchet beds Qg Pasco gravel Tp Pomona Member
( T1, T2, T3 T4)
Terraces developed on Qt and Qg r
0 2000 4000 HORIZONTAL SCALE IN FEET WASHINGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT NOS. 1'& 4 GEOLOGIC CROSS-SECTION D-D'HEET 5 OF 5
MAY, 1980 UE
& C CONTRACT ¹ 44013 SHANNON & WILSON, INC.
Geotechnical Consultants Portland Ore on FIG.9
l /
/)>> ', iaaf'/gI r i'
596 I//
i jl jyj 0
s diff
/
/
f
',love ying Dodge.(.
I'l Well. -- "
f998 5,.l/
(
h5 o
4'i iiiw e' I/PV 996
/
Vtjatef/
~
ell ISO9~ j/,'
]
(
\\
(
.~~I
', /'
ROAD 89$
(
jo'p9~
/r 6
r'- >j l
jl
)g ~iiii
.= P=-
. 'Z 0
Miles 0
SCALE 1:24000 I+ 4 ~~. ~ P~-, '$li WASHINGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT NOS.
1 8l 4 LOCATION IvIAP BUROKER FAULT '
/
lj/,IIjj/ /'!,'X';.
QJ /l'~l "J /
Kilometers MAY, 1980 UE 8
C CONTRACT 8, 44013 BASE MAP TAKEN FROM U.S.G.S.
TOPOGRAPHIC 7.5'UADRANGLE OF BUROKER, L
Geotechnical Consultants Portland Ore on FIG.
10
WEST EAST Soil (A) horizon C
v ~
A V A 1
v<+
C I
Dodge Basalt
?
C L V A 4 A
Red-brown loess (Palouse Formation)
~ v
~.
p, V " 4. ~ " " '7
~'
V J h
f'
'I A V g
4 V f b
)
L C
I
~
f L
V I I'
+v >V ~>
L A
g f (
Red-gray basalt Debris Debris Russell Creek Road Tan loess l ~
Greenish-gray basalt Fractures with caliche seams AVA1%+1VAVI' I RAP I t NOT TO SCALE WASHINGTON PUBLIC POWER SUPPLEY SYSTEM NUCLEAR PROJECT NOS.
1
& 4 GEOLOGIC SKECTH OF BUROKER FAULT MAY:, 19QO UE & C CONTRACT.
P. 44013 SHANNON
& WILSON, INC.
Geotechnical Consultants
- Portland, Oregon F I G
~ 'll
R R R R R A R R R % R R R R R R R
OVERLAY FIGURE 12 a)
Exposure of the Buroker Fault and lithologic units in a road cut along the Russell Creek Road.
b)
Details of reverse fault juxtap'osing the Palouse Formation against the Dodge Basalt.
- FIG, 12