Origin and Evolution of the Sierra Nevada and Walker Lane themed issue Pliocene sinistral slip across the Adobe Hills, eastern California–western Nevada: Kinematics of fault slip transfer across the Mina defl ection Sarah Nagorsen-Rinke1,*, Jeffrey Lee1, and Andrew Calvert2 1Department of Geological Sciences, Central Washington University, Ellensburg, Washington 98926, USA 2U.S. Geological Survey, Menlo Park, California 94025, USA ABSTRACT faults are consistent with simple shear/couple wide deformation zone. The Mina defl ection clockwise block rotation within a broad dex- transfers slip northward onto northwest-striking The Adobe Hills region (California and tral shear zone. Vertical axis block rotation dextral faults of the central WLB (Figs. 1B and Nevada, USA) is a faulted volcanic fi eld data are needed to test this interpretation. 2). Thus, the Mina defl ection defi nes an east- located within the western Mina defl ection, We propose that a set of faults subparallel to northeast–trending right-stepping relay zone a right-stepping zone of faults that con- Sierra Nevada–North America motion and within a dominantly northwest-trending dextral nects the northern Eastern California shear associated releasing steps, located west of the shear zone. zone (ECSZ) to the south with the Walker White Mountains fault zone and east of Three mechanisms have been proposed to Lane belt (WLB) to the north. New detailed the Long Valley Caldera, transfer a portion explain the fault kinematics that accommodate geologic mapping, structural studies, and of dextral Owens Valley fault slip northwest- displacement transfer across the Mina defl ec- 40Ar/39Ar geochronology in the Adobe Hills ward onto the sinistral faults in the Adobe tion: (1) the displacement-transfer model (Fig. allow us to calculate fault slip rates and test Hills. Dextral slip distributed across faults 3A) (Oldow, 1992; Oldow et al., 1994), in which predictions for the kinematics of fault slip between the White Mountains fault zone and connecting faults transfer slip via normal slip; transfer into the Mina defl ection. The Adobe the Sierra Nevada and east of the Fish Lake (2) the transtensional model (Oldow, 2003) (Fig. Hills are dominated by Pliocene tuffaceous Valley fault zone may account for the appar- 3B), in which oblique (sinistral) normal slip sandstone, basaltic lavas that yield 40Ar/39Ar ent discrepancy between summed long-term occurs along the connecting faults; and (3) the ages between 3.13 ± 0.02 and 3.43 ± 0.01 Ma, geologic slip rates and present-day geodetic simple shear couple/fault block rotation model and basaltic cinder cones. These Pliocene rates across the northern ECSZ. Fault slip in (Wesnousky, 2005) (Fig. 3C), in which sinistral units unconformably overlie Middle Miocene the Adobe Hills is part of a regional pattern slip occurs along the connecting faults. Geo- latite ignimbrite that yields an 40Ar/39Ar age of initiation and renewal of dextral, sinistral, logic map relations, structural data, and seis- of 11.17 ± 0.04 Ma, and Quaternary tuffa- and normal fault slip during the Pliocene micity in the northern ECSZ, Mina defl ection, ceous sands, alluvium, and lacustrine depos- that extends from lat ~40°N to ~36°N within WLB, and Basin and Range Province led Oldow its cap the sequence. Northwest-striking nor- the ECSZ-WLB and along the western mar- (1992) and Oldow et al. (1994) to propose the mal faults, west-northwest–striking dextral gin of the Basin and Range Province. This displacement-transfer model for the Mina faults, and northeast-striking sinistral faults regional deformation episode may be related defl ection, whereby extension across northeast- cut all units; the northeast-striking sinistral to changes in gravitational potential energy. striking normal faults proportionally accom- faults are the youngest and most well devel- modates the magnitude of Middle Miocene to oped fault set. We calculate ~0.1 mm/yr of INTRODUCTION Pliocene dextral fault slip transferred between approximately east-west horizontal exten- the northern ECSZ and central WLB (Fig. 3A). sion and northwest dextral shear since the Geologic and geodetic studies indicate that Using a combination of global positioning sys- Pliocene. The prominent northeast-striking the San Andreas fault accommodates ~75%– tem velocities, earthquake focal mechanisms, sinistral faults offset basalt ridgelines, nor- 80% of relative dextral motion between the and fault-slip inversions, Oldow (2003) postu- mal fault–hanging-wall intersections, a Pacifi c–North American plates, and the East- lated that instantaneous deformation across the channelized basalt fl ow, a basalt fl ow edge, ern California shear zone (ECSZ)–Walker Mina defl ection region is currently accommo- and a basalt fl ow contact a net minimum of Lane belt (WLB) accommodates the remaining dated by transtension (Fig. 3B). In this model, 921 ± 184 to 1318 ± 264 m across the Adobe 20%–25% (Fig. 1A) (e.g., Dokka and Travis, deformation in the western Mina defl ection is Hills. These measured sinistral offsets yield 1990; Dixon et al., 1995, 2000; Bennett et al., characterized by extension-dominated trans- a minimum Pliocene sinistral fault slip rate 2003; Frankel et al., 2007; Lee et al., 2009a). tension, whereas the eastern part is character- of 0.2–0.5 mm/yr; our preferred minimum In the northern ECSZ, dextral shear is primar- ized by wrench-dominated transtension. Fault slip rate is 0.4–0.5 mm/yr. The geometry ily accommodated along four major northwest- geometries, sinistral offset, and paired basins at and orientation of the prominent sinistral striking dextral faults (Fig. 1B). These faults the ends of active east-northeast–striking faults transfer slip northward onto several smaller in the Mina defl ection led Wesnousky (2005) *Present address: Freeport-McMoRan Copper & primarily east-northeast–striking faults within to hypothesize that during the Holocene, fault Gold, P.O. Box 586, Bagdad, Arizona 86321, USA. the Mina defl ection, an ~125-km-long, ~45-km- blocks bounded by northeast-striking sinistral Geosphere; February 2013; v. 9; no. 1; p. 37–53; doi:10.1130/GES00825.1; 10 fi gures; 3 tables; 3 supplemental fi les. Received 18 May 2012 ♦ Revision received 28 September 2012 ♦ Accepted 27 October 2012 ♦ Published online 11 January 2013 For permission to copy, contact [email protected] 37 © 2013 Geological Society of America Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/9/1/37/3344754/37.pdf by guest on 28 September 2021 Nagorsen-Rinke et al. 40° 121° 120° 124°W 44°N HLF AB112°W 050 44°N MVF Tertiary volcanic kilometers cover Plain WSFZ Snake River Cascades Juan de Fuca North American Plate 39° Plate CNSB Reno WLB 119° ISB Sierra Nevada Great Valley Lake MD PLF Tahoe S ECSZ Colorado a Carson 36°N n A Plateau 124°W n domain d 36°N re Yerington a 112°W s fa Pacific Plate ult 38° Bodie Hills region WRF 118° GHF Figure 1. (A) Simplifi ed tectonic map of the western U.S. Cordillera showing the modern plate boundaries and tectonic provinces. Basin and PSF Range Province is in medium gray; Central Nevada seismic belt (CNSB), BSF eastern California shear zone (ECSZ), Intermountain seismic belt (ISB), Sierra Nevada CF Candelaria and Walker Lane belt (WLB) are in light gray; Mina defl ection (MD) is QVF Hills in dark gray. (B) Shaded relief map of the WLB and northern part of Mina the ECSZ showing the major Quaternary faults. Solid ball is located on deflection the hanging wall of normal faults; arrow pairs indicate relative motion 37° Bishop across strike-slip faults; white dashed box outlines location of Figure 2; light gray shaded areas show the Mina defl ection and the Carson WMFZ domain. BSF—Benton Springs fault; CF—Coaldale fault; DSF—Deep 117° Springs fault; DVFCFLVFZ—Death Valley–Furnace Creek–Fish Lake Silver Peak DSF Valley fault zone; GHF—Gumdrop Hills fault; HLF—Honey Lake fault; Fig. 2 area HMF—Hunter Mountain fault; MVF—Mohawk Valley fault; OVF— OVF Owens Valley fault; PLF—Pyramid Lake fault; PSF—Petrifi ed Springs DVFCFLVFZ fault; QVF—Queen Valley fault; SLF—Stateline fault; SNFFZ—Sierra Nevada frontal fault zone; WMFZ—White Mountains fault zone; WRF—Wassuk Range fault; WSFZ—Warm Springs fault zone. SNFFZ HMF SLF 36° faults rotated clockwise in response to north- of ~74° and ~14° since the Miocene and Plio- suggesting that clockwise rotation is temporal west-dextral shear across the Mina defl ection cene, respectively (Rood et al., 2011). These and/or occurs in discrete zones within the Mina (Fig. 3C). Paleomagnetic studies in the eastern data suggest that the Wesnousky (2005) model defl ection. Mina defl ection imply clockwise rotation of is also applicable to older deformation within The results from new detailed geologic map- 20°–30° since Late Miocene to early Pliocene the Mina defl ection. In contrast, geologic stud- ping, kinematic, and 40Ar/39Ar geochronology time (Petronis et al., 2007, 2009), and paleo- ies centered on Quaternary faults in the Queen studies completed in the Adobe Hills, west- magnetic studies in the northwestern corner of Valley area did not yield evidence for recent ern Mina defl ection, are reported in this paper. the Mina defl ection indicate clockwise rotations clockwise block rotation (Lee et al., 2009b), These data allow us to test models for fault 38 Geosphere, February 2013 Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/9/1/37/3344754/37.pdf by guest on 28 September 2021 Pliocene fault slip across the Adobe Hills slip transfer across the Mina defl ection. From 119.00 118.75 118.50118.25 118.00 these data, we infer that a portion of dextral slip s in ta along the Owens Valley fault is transferred to n ou the sinistral faults in the Adobe Hills and that SN-NA M ior Pliocene deformation in the Adobe Hills is part Excels of a regional Pliocene event the length of the Figure 4 N ECSZ-WLB.