U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY

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Table 1. Characteristics of young faults in the Lovelock 1 ° by 2 ° quadrangle [See figure 1 for area boundaries]

Northwest Central East

Orientation Length (km) Percent Length (km) Percent Length (km)

90.0 to 80° 79.9 to 70° 69.9 to 60° 59.9 to 50° 49.9 to 40° 39.9 to 30° 29.9 to 20° 19.9 to 10° 09.9 to 0,0°

359,9 to 350° 349 .9 to 340° 339 .9 to 330° 329 .9 to 320° 319.9 to 310° 309,9 to 300° 299,9 to 290° 289,9 to 280° 279,9 to 270°

Total (km)

Arna (km2)

Density (km/km2)

Number

Density (no./km2)

Mean length (km)

5,4

6,6 25.4 42.0 72.4 103.2 80.2 23.8 17.6 2,0

32,6 3,6 5,2 2,2

422 2

4880

0,087

82

0,017

5,1

L3

L6 6,0 9,9 17,l 24.4 19,0 5,6 4.2 05 7,7 0,9 L2

!U l.llQJ)

7,0 L4 2,0 0.4

7,4 L5 2L6 16.4 3.2 9.4 42,6 8.4 126,0 24.7 26.4 119,0 233 IL8 94,8 18,6 22.4 29,0 5,7 9,6 24,8 4,9 12.0 22,8 4,5 10.8 3.4 0,7

2,0 0.4 4.0

lUi 2..i ~ l.llQJ) lllW

10630 3440

0,048 0,037

107 23

0.010 0,()()7

4,8 5.6

Percent

16.9 73

20.6 9.2 175 75 9.4 8.4

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APPl!OX IMA TE MEA N DECLINATION, 1991

Map unit

UnitQ3

UnitQ2

Unit Ql

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SCALE 1:250 000

5 E ==========io---========i5===============''<'0========i'5'==============''a:o:::::=======--'i25 MIL ES

5=====a:o=====:e'=========''c:o=====''E5'========3'0=====:'J25 KILOM ET ERS

CONTOUR INTERVAL 200 FEET WITH SUPPLEMENTARY CONTOURS AT 100 FOOT INTERVALS

NATIONAL GEODETIC VERTICAL DATUM OF 1929

Table 2. General photogeologic and geomorphic criteria used to estimate general ages of piedmonr surfaces

Age

Holocene (0 lo 10 ka)

Lale Pleistocene (10 lo 130 ka)

Early to middle Pleistocene (0.13 to 1.5 Ma)

Depth of dissection

Shallow to none; generally < 3 m

Shallow to moderate; typically 2-6 m

Moderate to deep; commonly >10 m

Drainage net morphology

Predominantly radial from fan apex.; channels typically poorly to moderately well defined

Predominantly distributar.")'; howeveT, some channels head on piedmont; well-defined channels

Predominantly subparallel; well-def med channels

Internuve morphology

Typically poorly defined; bar and swale micro-topography common on most surfaces

Typically well defined; surfaces broad and nat with abrupt margins

Well defined; older intcrfluve surfaces (ballenas) commonly narrow and irregular

Geomorphic Typical General relations geomorphic field criteria

environments

Surfaces cut pluvial Distal piedmont Unweathered to shorelines and (or) surfaces; channels slightly weathered; late Pleisl.ocene and terraces in very weak to weak glacial moraines proximal areas; soil development

(proximal surlaces along some highly active range fronts)

Surfaces overlain Proximal to distal Weakly to by pluvial piedmont surfaces; moderately wel1 shorelines and (or) some inset terraces developed soils; latest Pleistocene interlocking stone glacial moraines pavements

Sw-faces overlain Generally confined Moderately to very by pluvial shore- to intermediate and well developed lines and (or) latest prm.imal piedmont soils; interlocking Plcis1:'icene glacial arnas to highly degraded moraines stone pavements

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Mapped in 1989-90 by J.C. Oohrenwend and MA McKitt ri ck Edited by C.L. Ostergren; prepared by Lori Moore Manuscript approved for publica tion June 28, 1991

116°

Figure 1. Rose diagrams summarizing orientation of young faulting. Number indicates mean fault trend. See table 1 for data,

MISCELLANEOUS FIELD STUDIES MAPMF-2178

I INTRODUCTION

The Sta of Nevada occupies most of the central and western parts of the Great Basin, the largest t ctumcally active region within the Basin and Range geomorphic province of North Amcnca. The topography of

· rdgion ~ typifibd by generally north-northwest- to northeast-trending, subparallel mountain ranges separated by luvi11 basins of sfutllar plan form and orientation. This classic Basin and Range physiography is the product of at

~ ast lwo ph~es o~' middle to late Cenozoic ex.tensional faulting (Zoback and others, 1981; Eaton, 1982; Stewart, t?83)1 and niost of basins and ranges of the region are at least partly bounded by late Cenozoic faults. The earlier yhasef of ex.thnsion was marked by widespread shallow detachment faulting that began at approximately 35 Ma and ocallr continued rnto the time of the later phase (Eaton, 1982; Stewart, 1983). The later phase, which was orninated by higl{-angle, more deeply penetrating block faulting, may have begun locally at about 17 Ma and ontinucs er,isodica1.Jy to the present time (Christiansen and McKee, 1978; Eaton, 1982). This map, one of a series of 0 b~ 2° qu!tdrangle maps showing young faults in Nevada, provides a generalized picture of the late Tertiary and uaui=rnary [ faulting that is associated with the latter ex.tensional phase. These young faults are a primary cteiant of the r1 esent configuration of ranges and basins within the quadrangle.

MAPPING PROCEDURE

I Young rr ulls a,e he,ein defined"' !hose fau]l,; lhal ha,e unde,gone ]ales! Te,tia,y and (m) Qualemru-y ovcment. These faults arc commonly marked by a variety of diagnostic constructional landforms and other

surfif ial ph1enomeba that can be readily identified and mapped on aerial photographs. These features include (1) scarps on t1atesl ~ertiary and (or) Quaternary surficial deposit~. volcanic strata, or g;eomorphic surfaces (either erosf nal or depo~it:i.onal); (2) prominent alignments of linear drainageways, ridges and swales, active springs and (or) fpring tfeposits, and linear discontinuities of structure, rock type, and vegetation; and (3) abrupt, steeply sloping rangf frontk with ~ asal scarps, faceted spurs, 'wineglass valleys,' and elongate drainage basins with narrow valley flo, s (Thornbury,j ~969; Bull, 1977; Bull and McFadden, 1977; Wallace, 1977, 1978). I

Natio~ High Altitude Program (NHAP), 1:58,000-nominal-scale, color-infrared photographs were used for photo geologic interpretation. This mapping was transferred directly lo 1/2° hy 1 ° topographic quadrangle maps that 1Werc enlarge to the scale of the photographs. These maps were reduced and compiled at 1 :250,000 scale. This compilation was then compared with previous mapping of young faults within the quadrangle (Wallace, 1979), and sigmficant differflccs between maps were resolved. Following comparison and resolution with this previous maWing, the final 1:250,000-scale compilation was digitized using a GTCO digiti'zing board connected to a Madintosh 1II minlcomputer. The resulting vector file was converted to raster format (cell size= 200 m by 200 m) and ]analyzed to 1etennine the approximate length and average orientation of each fatllt segment. These data are summarized in table 1 and figure l.

Gener~ age.s of surficial deposits and erosion surfaces cut by young faults were estimated using a variety of pho'togeologic and geomorphic criteria (table 2). These age estimates provide ar general indicatiun of the approximate ti.ming of young faulting throughout the quadrangle. However, it should be emphasized that these data do rot necessaril~ reflect the age of most recent surface rupture along any particular fault segment. Rather, they provide only vei:y general (and commonly somewhat biased) age constraints on this sm;face faulting. Age estimates bas~d on photogC;-O logic analysis of surficial deposits and erosion surfaces are, at best, both tentative and imprecise. Moreoverr the distribution of these deposits and surfaces is inherently biased by geomorphic process and emjironment. Fo[ ex.ample, in those areas of the Great Basin where range uplift rates Je low to moderate, remnants of older gbomoIP,hic surfaces tend to be concentrated in proximal piedmont areas, whereas younger surficial deposits tend to acbumulJte on distal piedmonts and basin flats . Consequently, young faults 1dcated in intrabasin areas are mofe likely to offset younger surface deposits then are faults located along range frclnts or in proximal piedmont areas. Therefore[ inferences based on these data regarding the temporal distribution of Young fault activity should be usJi with lcaut:i.o~. I

I In addjtion to limitations imposed by map and photo scales, one other factor also significantly constrains th1 resolution oflthe present map. The photography used in this analysis, which was Jcquircd under high sun-angle condition~, is nzt well suited for the discrimination and mapping of subtle topographic features. Consequenlly, re+ arnination o any of the fault systems shown on this map using larger scale and (or) lower sun-angle aerial phf tography wo I Id very likely reveal a substantial number of additional young fault segbents.

[ AT/ ERNS OF LATEST TERTIARY AND QUATERNARY FAULTING

Severt. factors significantly influence the preservation of fault-related 1l ndforms and, therefore, the a~arent distrib ti.on of young faults as indicated by the distribution of these l~dfonns can be significantly biased. These f!Ctors include (1) composition, induration, and structural integrity of the rock or sediment type(s) un?,crlyidg fault scarps; (2) local geomorphic environment of the scarp or other fault-related landform; (3) regional biimatib conditions and paleoclimatic variations; and (4) magnitude and iecurrence of fault movement (\\fallace, 1977;j Bucknam and Anderson, 1979; Nash, 1980, 1984; Hanks and 0th.ch, 1984; Mayer, 1984; Pierce and Colrilan, 1~86; Machettc, 1986, 1988, 1989). Therefore, the distribution of yof ng faults shown on this map pr?vides, at bcsh only an approximate and somewhat biased picture of late Tertiary and Quaternary faulting within th~ quadrangle/ Specifically, faults having a long history of recurrent movement, juxtaposing bedrock and al1uvium( or cu\ting upper Cenozoic lava flows and (or) welded ash-flow luffs tend fu be overrepresented, whereas faplts of pre-late Pleistocene age cutting unconsolidated surficial deposits and having either short histories of recurrent movcflent or long recurrence intervals tend to be underrepresented. Scarp1s developed on volcanic rocks rn ry be preserved for periods of as much as 10 m.y. By comparison, scarps oh the fluvially active parts of piedmont surfa!es would likely be completely destroyed within a few thousand years at most, and even on inactive p~edmo~t surf~ces, fault scarps on unconsolidated alluvial fill are significantly !rounded within 10,000 years (fallace, 197f ), and low scarps would be sufficienlly degraded to be unrecognizable on standard aerial p~otography W)thin a few hundred thousand years (Wallace, 1977; Hanks and otheis, 1984; Machette, 1989). I Youn~ faulting within the Lovelock quadrangle is variable (table 1 and fig '. l). Young fault densities west

3?d northwest lof the Black Rock and Smoke Creek Deserts average approx.imatel}' 0.09 km/km2, and fault trace orientatibns average approximately Nl 0°W. This area is largely underlain by volcanic rocks of late Miocene age. lit contrast, y9ung faults are almost completely absent from a 20- to 25-km-wide[ north-northeast-trending zone of ex.terisive 'Plrdiments that extends westward from and roughly parallels the valle~ of the Humboldt River in the ejist~ceritral Pft of the quadrangle. In all other areas of the quadrangle, however, major range-bounding fault

~nes are almost uniformly distributed; young fault densities average approximatJly 0.05 km/km2 and fault trace ientat:i.ons a~erage about N15°E (table 1 and fig. 1). All of these fault zones have been active during Quaternary

( , nd quite pqssibly late Pleistocene) time, and at least five of them displa~ abundant evidence of latest Pleistocene(l tj-30 ka) and (or) Holocene (0-10 ka) movement (for ex.ample, the w1est flanks of the Fox. and Lake !anges( sout,hwest flank of the Granite Range, east flank of the Shawave Mountams, and west flank of the

umboldt Ral\ge). Late Pleistocene and (or) Holocene movement also has occu1 ed within two north-northeast­ending systeins of distributed intrabasinal faulting. These intrabasinal systems are located near the center of the

i uadrarlgle {et st of the Selenite Range and northeast of the Trinity Range).

I I I REFERENCES CITED

Bucknam, R.C., and Anderson, E., 1979, Estimation of fault-scarp ages frob a scarp-height--slope-angle I I relatfonship: Geology, v. 7, p. 11-1'4.

Bull, W.B., 1~ 77, Tectonic geomorphology of the Mojave Desert, California: U.S. Geological Survey, Office of

I Ear quakes, Volcanoes, and Engineering, Contract Report 14-08-001-G-394, Menlo Park, Calif., 188 p. / iull, W.B., fil}d McFadden, L.D., 1977, Tectonic geomorphology north and south of the Garlock fault., California, Lin J?aehring, D.C., ed., Geomorphology in arid regions: Proceedings 8th Annual Geomorphology Sym,rosium, State University of New York, Binghamton, p. 115-137. I

Christi en, R.L., and McKee, E.H., 1978, Late Cenozoic volcanic and tectonic evolution of the Great basin and I ColJ mbia intermontane basin: Geological Society of America Memoir 1b 2, p. 283-311. Eaton, G.P., 1982, The Basin and Range Province: Origin and tectonic significarice: Annual Reviews Earth and j Plan'etary Science, v. 10, p . 409-440. I ranks, T.C.,r Bucknam, R.C., Lajoie, K.R., and Wallace, R.E., L984, Modific11-tion of wave-cut and faulting­

con ollcd landforms: Journal of Geophysical Research, v. 89 (B7), p. 5771-5790. Machette, M N., 1986, History of Quaternary offset and paleoseismicity along lthe La Jencia fault, central Rio

Grap.de rift, New Mexico: Seismology Society of America Bulletin, v. 7~. p. 259-272. 198~. Quaternary movement along the La Jencia fault, central New 11ex.ico: U. S. Geological Survey Professional Paper 1440, 81 p. 19~9. Slope-morphometric dating, in Forman, S.L., ed., Dating methods applicable to Quaternary

geologic studies in the western Uniled Stales: Utah Geological and/ Mineral Survey Miscellaneous Pu1i_lication 89-7, p. 30-42.

Mayer, L., 1 ( 84, Dating Quaternary fault scarps formed in alluvium using morphological parameters: Quaternary Re~earch., v. 22, p. 300-313. I

Nash, D.B., 1980, Morphological dating of degraded normal fault scarps: Journal of Geology, v. 88, p. 353-360. ___ I 19~4, Morphologic dating of fluvial terrace scarps and fault scarps nJar West Yellowstone, Montana:

Ger logical Society of America Bulletin, v. 95, p. 1413-1424. I Pierce, K.L., and Colman, S.M., 1986, Effect of height and orientation (microclimate) on geomorphic degradation

rales and processes, late-glacial terrace scarps in central Idaho: Geological Society of America Bulletin, V, 97, p. 869-885. '

Stewart, J.H., 1983, Cenozoic structure and tectonics of the northern Basin and Range Province, California, Ne1b da and Utah, in The role of heat in the development of energy and mineral resources in the northern Bap.in and Range Province: Geothermal Resources Council, Special Report 13, p. 25-40.

Thornbury, e1-D , 1969, Principles of Geomorphology: John Wiley & Sons, Inc,., New York, 594 p Wallace, R,c,-, 1977, Pro files and ages of young fault scarps, north-central Nevada: Geological Society of

I Arjlerica Bulletin, v. 88, p. 1267-1281. I

___ 1178, Geometry and rates of change of fault -generated range fror ts, north-central Nevada: U.S. Giological Survey Journal of Research, v 6, p. 637-650

___ 19 f9, Map of young fault scarps related to earthquakes m north central Nevada· U.S. Geological Survey Open File Report 79-1554, scale 1:125,000

Zob.tck, ML., Anderson, R.E., and Thompson, G.A., 1981. Cainozoic evolution of the state of stress and style of tectonism of the Basin and Range Province of the western United Stat~s, in Vine, F.T., and Smith, A.D., e~s., Extensional tectonics associated with convergent plate boundaries: The Royal Society, London, p. 1s9.216, I I I

,-~ Fault scarps on Quaternary surficial deposits or Quaternary erosional surfaces-­Scarps on Quaternary deposits or Quaternary erosion sw-faces other than those displacements associated with known historic earthquakes. Hachures inaicate dov.nslope direction of scarp. Symbol indicates approximate age of offset surficial dep6sit or erosion surface:

Q3 Q2-3 qz Ql-2 QI

___ J __

...._ --

I ..--+----'

Holocene (0-10 ka) [ Latest Pleistocene and (or) Holocene (0-30 ka) Late Pleistocene (10-130 ka) Early to middle and (or) late Pleistocene (0.01-1.5 Ma) Early 10 middle Pleistocene (0.13-1.5 Ma)

Photogeologic and geornorphic criteria used to estimate ages are summarized in table 2

Fault-related lineaments un Quaternary surficial deposits or on Quaternary erosion surfaces--Alignments, in Quaternary surfie;ial deposits or across Quaternary erosional surfaces, of one or more of the following fearures: linear reaches of stream channels, linear stream valleys, shallow linear swales,1 springs, vegetation discontinuities. Commonly associated with fault scarps on Quaternary :deposits and (or) erosional surfaces. Age designations as above

Major range-front faults--Faults bounding tectonically I active fronts of major mountain ranges. These range fronts are characterized by: fault j uxtaposition of Quaternary alluvium against bedrock, fault scarps and lineaments on surficial deposits along or immediately adjacent to range front, a general absence of ped1iments, abrupt piedmont-hillslopc transitions, steep bedrock slopes, faceted spurs, wineglass valleys, and subparallcl systems of high-gradient, narrow, steep-sided canyons orthogdnal to range front. Only mapped in area.,;; along range front where fault scarps and (or) lineaments on Quaternary surficial deposits or on Quaternary erosion surfaces are absent

Faults juxtaposing Quaternary alluvium against bedrock (other than major range-front faults)--Morphologically similar to rrl.ajor range-front faults except that associated fault systems are significantly less cxtensi~e and fault scarps are substantially lower, shorter, and less continuous. Solid lines indit ate locations where fault scarps are abrupt and well-defined; long dashes indicate locations j herc scarps are less well defined

Faults forming scarps and (or) prominent topographic lineaments on Tertiary volcanic or sedimentary rocks--These scarps havb morphologies ranging from partly rounded and moderately dissected to undissected. ToPpgraphic lineaments are composed of alignments of one or more of the following landforms: abrupt scarps, linear hillside ridges, hcnche..,; and trenches, linear reaches of stream channejs and small stream valleys, ridge-crest saddles and cols, linear depressions and small closed basins. Many of these faults form closely spaced groups in areas underlain by Tertiary ash-Oow tuffs and lava flows

RECONNAISSANCE PHOTOGEOLOGIC MAP OF YOUNG FAULTS IN THE LOVELOCK 1 ° BY 2° QUADRANGLE, NEVADA AND CALIFORNIA By I

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Any use of trade, product, or firm names in this publicat ion is for descriptive purposes only and does not imply endorsement by the U.S Government

John C. Dohrenwend, Mary Anne McKittrick, and Barry C. Moring 1991 f 0 1

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For sa le by U.S. Geologira l SuM!'f'. Map Distributioo. l Box 252115. Federal Cetitef. Denver. CO 1!(1"225

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