Downloaded from geology.gsapubs.org on June 3, 2010 Geology Kinematics of the Eastern California shear zone: Evidence for slip transfer from Owens and Saline Valley fault zones to Fish Lake Valley fault zone Marith C. Reheis and Timothy H. Dixon Geology 1996;24;339-342 doi: 10.1130/0091-7613(1996)024<0339:KOTECS>2.3.CO;2 Email alerting services click www.gsapubs.org/cgi/alerts to receive free e-mail alerts when new articles cite this article Subscribe click www.gsapubs.org/subscriptions/ to subscribe to Geology Permission request click http://www.geosociety.org/pubs/copyrt.htm#gsa to contact GSA Copyright not claimed on content prepared wholly by U.S. government employees within scope of their employment. 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Notes Geological Society of America Downloaded from geology.gsapubs.org on June 3, 2010 Kinematics of the Eastern California shear zone: Evidence for slip transfer from Owens and Saline Valley fault zones to Fish Lake Valley fault zone Marith C. Reheis U.S. Geological Survey, MS-913, Federal Center, Box 25046, Denver, Colorado 80225 Timothy H. Dixon Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, Florida 33149 ABSTRACT kinematic evolution of the Eastern Califor- Late Quaternary slip rates and satellite-based geodetic data for the western Great nia shear zone. Basin constrain regional fault-slip distribution and evolution. The geologic slip rate on the Fish Lake Valley fault zone (the northwest extension of the Furnace Creek fault zone) GEOLOGIC DATA increases northward from about 3 to 5 mm/yr, in agreement with modeled geodetic data. The right-oblique Fish Lake Valley fault The increase coincides with the intersections of the Deep Springs fault, connected to the zone extends north-northwest 80 km from Owens Valley fault zone, and of other faults connected to the Saline Valley fault. The the Furnace Creek–Death Valley fault sys- combined geologic and geodetic data suggest that (1) the northwest-striking faults of the tem along the east side of the White Moun- Eastern California shear zone north of the Garlock fault are connected by north- to north- tains (Fig. 1) and is characterized by large, east-striking normal faults that transfer slip in a series of right steps, and (2) the amount steep fault scarps, offset drainages, and shut- and distribution of slip among the many faults of this broad, complex plate boundary have terridges (Brogan et al., 1991). Holocene al- changed through time. luvium filling the northern part of Fish Lake Valley is cut by many north-striking faults INTRODUCTION Mapping of Quaternary deposits and that transfer lateral offset eastward by an Recent geologic (Dokka and Travis, 1990; faults in Fish Lake and Deep Springs valleys extensional right step to the Emigrant Peak Oldow, 1992) and geodetic (Sauber et al., (Reheis, 1992; Reheis et al., 1995) docu- normal-fault zone (Fig. 2). We suspect that 1994; Dixon et al., 1995) studies have shown ments the structural connection between the this step is part of a larger step that transfers that about 25% of the relative motion be- FLVFZ and the Deep Springs fault (Fig. 2) slip from the FLVFZ to faults of the Walker tween the Pacific and North American and provides Quaternary slip rates during Lane northeast of the Excelsior Mountains plates (;46–48 mm/yr; DeMets et al., 1994; different time periods. These data demon- (Reheis and Noller, 1989), but a kinematic Humphreys and Weldon, 1994) is accommo- strate slip transfer between the Owens Val- connection has not yet been demonstrated. dated by dextral shear east of the San An- ley fault zone and the FLVFZ and suggest Deep Springs Valley is a closed basin dreas fault, mostly on faults in the Mojave slip transfer from the Saline Valley fault to about 25 km long between the White Moun- Desert and western Great Basin. South of the FLVFZ. We compare geologic slip rates tains and the Inyo Mountains (Fig. 2), the Garlock fault, faults of the Eastern Cal- to geodetic data and discuss implications for bounded on the east by the north-northeast– ifornia shear zone accumulated ;65 km of striking Deep Springs normal fault. The dextral offset since the late Miocene (Dokka fault is characterized by steep fault scarps in and Travis, 1990). To the north, several upper Pleistocene and Holocene deposits faults near Walker Lake (Fig. 1) in the (Bryant, 1989). The FLVFZ is structurally Walker Lane belt have accumulated 60–75 linked to the northeast end of the Deep km of dextral offset in the past 10 m.y. Springs fault by normal and sinistral faults (Oldow, 1992). Other faults to the west have (Fig. 2) (Reheis, 1992; Reheis et al., 1995). also been active (Dohrenwend, 1983). Be- Although the connecting faults mostly offset tween these two shear zones are three major basalt and granitic rocks, they also cut allu- northwest-striking dextral fault systems vium and fan deposits containing or overly- (Fig. 1): the Owens Valley and White ing the 760 ka Bishop ash. The Deep Springs Mountains fault zones, the Panamint Val- fault is probably also connected structurally ley–Hunter Mountain–Saline Valley fault with the Owens Valley and White Moun- system, and the Death Valley–Furnace tains fault zones (Fig. 2). Several short Creek–Fish Lake Valley fault system. Dixon north-striking faults in upper Pliocene de- et al. (1995) suggested that northeast-strik- posits within the Waucoba embayment step ing normal faults transfer slip among these eastward from the junction (a right step) of fault systems. However, their geodetic data the two fault zones and extend into a set of lack the resolution to verify slip transfer, and Figure 1. Map of late Cenozoic faults of west- northeast-striking faults in bedrock that par- geologic proof was lacking. An important ern Great Basin, modified from Oldow (1992). allel or connect to the Deep Springs fault. implication of the geodetic model is that sig- Faults (F) and fault zones (FZ): WAL—Walker The two southernmost of the bedrock faults Lane; WMFZ—White Mountains; OVFZ— nificant dextral shear is concentrated on the Owens Valley; DSF—Deep Springs; EVF— probably have Quaternary offset, for they lo- Fish Lake Valley fault zone (FLVFZ), Eureka Valley; SVF—Saline Valley; cally bound the sides of small, asymmetric which has received little attention in studies HMF—Hunter Mountain; TPF—Towne Pass; topographic basins within the Inyo Moun- of deformation of the Pacific–North Amer- PVF—Panamint Valley; FLVFZ—Fish Lake Val- tains (Nelson, 1966, 1971). ley; FCFZ—Furnace Creek; DVFZ—Death Val- ican plate boundary zone. Temporal evolu- ley; GF—Garlock; ECSZ—Eastern California Several normal faults in the Saline Range tion of the complex fault system composing shear zone. ML is Mono Lake; WL is Walker strike north-northeast from the north end of this zone has also received little attention. Lake; EM is Excelsior Mountains. the Saline Valley fault toward the south end Geology; April 1996; v. 24; no. 4; p. 339–342; 4 figures; 1 table. 339 Downloaded from geology.gsapubs.org on June 3, 2010 assuming that this contact was created at the beginning of deposition of unit Qpy, the slip rate is 4.4 mm/yr (3–6 mm/yr). However, these values are minimum estimates of the total slip rate, because slip across nearby sin- istral and normal faults that cut unit Qpy (Fig. 3) is not included. Thus, the actual late Quaternary slip rate for the fault zone could be as much as 5 mm/yr. Debris-flow levees on the surface of unit Qpy are offset right laterally about 120 m near the north end of the FLVFZ (Fig. 2; Reheis et al., 1993), and the slip rate is 1.8 mm/yr (range 1.1–3.3 mm/yr), a minimum value because possible offsets across subpar- allel to oblique secondary faults at the two localities are not included. This site has a lower slip rate than that at Furnace Creek because it is north of the beginning of the eastward stepover to the Emigrant Peak Figure 2. Geologic map of study area, showing Quaternary faults and slip-rate sites (star). fault zone. RVF—Round Valley fault; DSF—Deep Springs fault; EPFZ—Emigrant Peak fault zone; geodetic Fan deposits south of the intersection of stations are OVRO (Owens Valley Radio Observatory) and FL (Fish Lake); other abbreviations as in Figure 1. Sources of rates: Round Valley fault, Berry (1990); Volcanic Tableland (VT), Pinter the FLVFZ with north-striking faults in Eu- (1995); White Mountains fault zone, DePolo (1989); Owens Valley fault zone, Beanland and Clark reka Valley (Fig. 2) have beheaded drain- (1995); FLVFZ and Deep Springs fault, this paper. ages. Lateral offset is estimated by matching deposits of unit Qpy to tributary drainages of the FLVFZ (Fig. 1). These faults are bur- A large shutterridge south of Furnace across the fault zone.