Quaternary faulting in Queen Valley, California-Nevada: Implications for kinematics of fault-slip transfer in the eastern California shear zone– Walker Lane belt Jeffrey Lee† Jason Garwood* Department of Geological Sciences, Central Washington University, Ellensburg, Washington 98926, USA Daniel F. Stockli Department of Geology, University of Kansas, Lawrence, Kansas 66045, USA John Gosse Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4J1, Canada ABSTRACT transfer, block rotation, and simple shear Keywords: normal faults, strike-slip faults, models, within the dextral fault system pro- thrust faults, terrestrial cosmogenic nuclide New geologic map, tectonic, geomorpho- posed for the eastern California shear zone– geochronology, fault-slip transfer, Walker Lane logic, and terrestrial cosmogenic nuclide Walker Lane belt are not applicable to this belt, Eastern California shear zone. (TCN) geochronologic data document the part of the Mina defl ection. Rather, dextral geometry, style, kinematics, and slip rates fault slip is transferred by both a restraining INTRODUCTION on late Quaternary faults within the Queen westward step and a releasing eastward step. Valley, California-Nevada area. These data Restraining and releasing bends have been Modern deformation between the North provide important insight into the kinematics extensively documented at a range of scales American and Pacifi c plates is distributed across of fault-slip transfer from the dextral White in strike-slip fault tectonic settings globally, a wide zone of the western margin of North Mountains fault zone northward into the and they have been simulated in analog mod- America, from the San Andreas fault eastward Mina defl ection. Queen Valley is an ~16-km- els; thus, it is not surprising to document both into the western Basin and Range Province long, NE-trending basin bounded to the south within the ~630-km-long dextral shear zone (e.g., Bennett et al., 1999; Thatcher et al., 1999) by the White Mountains and underlain by that makes up the northern eastern Califor- (Fig. 1). Geodetic and geologic studies indicate four major Pleistocene to Holocene alluvial- nia shear zone–Walker Lane belt. Our results, that the San Andreas fault system accommodates fan surfaces. Four different fault types and combined with published slip rates for the ~75%–80% of the total relative plate motion. orientations cut and offset all but the young- dextral White Mountain fault zone and the The modern plate-boundary strain residual is est surfaces: (1) The normal-slip Queen Valley eastern sinistral Coaldale fault, suggest that transferred away from the San Andreas fault fault, which consists of a set of NE-striking, transfer of dextral slip into the Mina defl ec- system via the eastern California shear zone NW- and SE-dipping normal fault scarps that tion is partitioned into three different compo- northward into the Walker Lane belt and the cut across the SE side of the valley and offset nents: horizontal extension along the Queen Central Nevada seismic belt (Fig. 1). Geodetic all but the youngest surfaces; (2) discontinu- Valley fault, thrust faulting that merges into data indicate that right-lateral shear, at a rate of ous NE-striking, sinistral faults exposed on the the dominantly dextral slip along the Coy- ~9–13 mm/yr (Thatcher et al., 1999; Dixon et north side of the valley; (3) the NW-striking ote Springs fault, and dominantly sinistral al., 2000; Gan et al., 2000; Bennett et al., 2003; dextral Coyote Springs fault, which merges slip along the Coaldale fault. A velocity vec- Oldow, 2003; Hammond and Thatcher, 2007), into (4) a set of E-W–striking thrust faults. tor diagram of fault-slip partitioning across dominates within the eastern California shear Measured offsets across normal fault scarps Queen Valley predicts a small component of zone and Walker Lane belt, accounting for developed within 10Be TCN-dated surfaces contraction across the Coyote Springs and ~20%–25% of the total relative plate motion. yield minimum late Pleistocene horizontal western Coaldale faults. Contraction across In the northern eastern California shear zone extension rates of 0.1–0.3 mm/yr. Documented the Mina defl ection is consistent with global (north of the Garlock fault), dextral displacement fault geometries and slip orientations across positioning system data. An observed reduc- is funneled through a relatively narrow zone of Queen Valley suggest that fault-slip transfer tion in late Pleistocene fault-slip rates at the shear along four major subparallel strike-slip models, such as the extensional displacement northern end of the eastern California shear fault zones, the Stateline, Death Valley–Furnace zone and across the southwestern part of the Creek–Fish Lake Valley, Hunter Mountain– †E-mail: [email protected] Mina defl ection may be explained by distribu- Panamint Valley, and White Mountains–Owens *Present address: 928 Roosevelt Street, Ridgecrest, tion of slip across a much broader zone than Valley fault zones (Figs. 1 and 2). At the north- California 93555, USA. generally thought. ern end of the eastern California shear zone, GSA Bulletin; March/April 2009; v. 121; no. 3/4; p. 599–614; doi: 10.1130/B26352.1; 12 fi gures; 3 tables; Data Repository item 2008169. For permission to copy, contact [email protected] 599 © 2008 Geological Society of America Lee et al. formed as conjugate faults to the main dextral 124°W shear zone (Fig. 4B). Clockwise rotation of the 44°N 112°W blocks bounding the sinistral faults accommo- 44°N dated dextral slip. Wesnousky (2005) also noted Tertiary volcanic that paired normal-faulted basins exposed at the in ends of the sinistral faults imply that sinistral cover ver Pla Snake Ri faults have transferred slip between the basins and/or were formed as a consequence of clock- Cascades wise rotation. Different mechanisms for transferring slip Juan de Fuca North American plate between subparallel dextral strike-slip faults plate and connecting faults have been proposed to the north and south of the Mina defl ection. In CNSB the northern eastern California shear zone, Lee WLB et al. (2001) used structural, kinematic, and ISB Sierra Nevada geomorphic data from the Deep Springs fault (Fig. 2) to argue that domains of NE-striking Great Valley faults, bounded by NW-striking right-lateral strike-slip faults, exhibited no rotation and were dominated by dip-slip normal faults. Lee et al. (2001) argued that the mechanism of slip trans- ECSZ Sa Colorado fer was one of right-stepping, high-angle normal n faults in which the magnitude of extension was 36°N A Plateau 124°W n proportional to the amount of strike-slip motion d 36°N re transferred (Fig. 4A). In contrast, in the north- a 112°W s ern Walker Lane belt, between Reno and Yer- f a ington (Fig. 2), Cashman and Fontaine (2000) Pacific plate ult used paleomagnetic data to argue that domains of NE-striking faults, bounded by NW-striking right-lateral strike-slip faults, were dominated by clockwise rotation and left-lateral strike-slip Figure 1. Simplifi ed tectonic map of the western part of the U.S. Cordillera showing the major faults. Fault movement and block rotation within geotectonic provinces and modern plate boundaries. Basin and Range extensional province is a zone of distributed deformation accommodated in dark gray; CNSB (Central Nevada seismic belt), ECSZ (eastern California shear zone), ISB the right-lateral strike-slip motion (Fig. 4B). (Intermountain seismic belt), and WLB (Walker Lane belt) are in light gray. Fault-slip transfer from a relatively narrow (~25 km wide) and simple geometric zone of dextral shear northward into a broader (~60 km wide) and complex geometric zone of faulting individual NW-striking strike-slip fault systems defl ection, which transfers dextral slip from styles and slip orientations is one of the dis- abruptly swing eastward into an array of NE- to fault zones that made up the northern end of the tinctive structural characteristics of the Mina E-W–striking faults in the southern portion of eastern California shear zone to the northern defl ection. In this paper, we combine new geo- the central Walker Lane belt, which is known Walker Lane belt and Central Nevada seismic logic mapping and tectonic, geomorphologic, as the Mina defl ection (Figs. 2 and 3). The dra- belt (e.g., Oldow, 1992; Oldow et al., 2001; and terrestrial cosmogenic nuclide (TCN) geo- matic change in Cenozoic fault orientation that Stockli et al., 2003; Wesnousky, 2005; Tincher chronologic data from the Queen Valley area defi nes the Mina defl ection is attributed to geo- and Stockli, 2008). The curvilinear Cenozoic to determine fault geometries, slip orientations, metric control by the latest Precambrian–earli- faults in the Mina defl ection form a z-shaped and slip magnitudes that bear on the mechanism est Paleozoic rifted continental margin, which extensional relay zone that transfers dextral slip. of fault-slip transfer from the relatively narrow was mimicked by Phanerozoic depositional pat- Fault-slip transfer through this regional releas- dextral White Mountains fault zone to the broad terns and mid-Paleozoic through Mesozoic con- ing bend results in the formation of multiple deformation zone that defi nes the southern part tractional structures (e.g., Stewart and Suczek, rhomboidal pull-apart structures. Oldow (1992) of the Mina defl ection (Figs. 2 and 3). 1977; Speed, 1978; Oldow et al., 1989). and Oldow et al. (1994) postulated that strike Fault-slip transfer by extension, contraction, slip and transtensional slip across the dextral QUEEN VALLEY and/or rotation is common within strike-slip faults were transferred across the Mina defl ec- fault systems worldwide (e.g., McKenzie and tion by right-stepping normal faults in which the Geological Setting Jackson, 1983, 1986; Cunningham and Mann, magnitude of extension was proportional to the 2007) and has been simulated in analog models amount of transtension transferred (Fig.