Chasing the Garlock: A study of tectonic response to vertical axis rotation

Bernard Guest  Terry L. Pavlis   Department of Geology and Geophysics, University of New Orleans, New Orleans, Louisiana 70148, USA Heather Golding  Laura Serpa 

ABSTRACT vis, 1982; Gastil et al., 1967; Guest, 2001; Wagner and Hsu, 1988) Vertical-axis, clockwise block rotations in the Northeast Mo- overlain nonconformably by Tertiary and Quaternary volcanic rocks jave block are well documented by numerous authors. However, (Calzia, 1974; Davis, 1982; Davis and Fleck, 1977; Guest, 2001; Wag- the effects of these rotations on the crust to the north of the North- ner, 1998) (Fig. 2). The Mesozoic intrusions were emplaced in Jurassic± east Mojave block have remained unexplored. In this paper we Cretaceous time and were exposed at Earth's surface between Oligo- present a model that results from mapping and geochronology con- cene and middle Miocene time (Davis and Fleck, 1977; Golding, 2000; ducted in the north and central Owlshead Mountains. The model Guest, 2001). The Tertiary section in the Owlshead block is laterally suggests that some or all of the transtension and rotation observed variable (Golding, 2000; Guest, 2001; Snow et al., 1991), but typically in the Owlshead Mountains results from tectonic response to a has a basal red arkosic sand or ¯uvial conglomerate de®ning the sub- combination of clockwise block rotation in the Northeast Mojave Tertiary unconformity. The basal deposits are localized in paleotopo- block and Basin and Range extension. The Owlshead Mountains graphic lows and are unconformably overlain by a 1±2-km-thick vol- are effectively an accommodation zone that buffers differential ex- canic pile that includes a large, extinct volcanic center immediately tension between the Northeast Mojave block and the Basin and north of Wingate Wash (e.g., Golding, 2000; Wagner, 1998). In the Range. In addition, our model explores the complex interactions northern Owlshead block and southern , this volcanic that occur between faults and fault blocks at the junction of the pile is entirely middle Miocene in age. The bulk of the volcanic pile Garlock, Brown Mountain, and Owl Lake faults. We hypothesize erupted in a narrow time frame ca. 13.5 Ma; a few basalts as young that the bending of the Garlock fault by rotation of the Northeast as 12.5 Ma are at the top of the pile (e.g., Davis and Fleck, 1977; Mojave block resulted in a misorientation of the Garlock that Golding, 2000; Guest, 2001). forced the Owl Lake fault to break in order to accommodate slip This volcanic section is critical for regional reconstructions be- on the western Garlock fault. Subsequent sinistral slip on the Owl cause (1) the rocks predate the main period (12 Ma to present) of Lake fault offset the Garlock, creating the now possibly inactive extensional tectonics in the adjacent region (e.g., Wright Mule Springs strand of the Garlock fault. Dextral slip on the et al., 1991; Snow and Wernicke, 2000) and (2) the deposits form a Brown Mountain fault then locked the Owl Lake fault, forcing the regional blanket that is not extensively disrupted by extensional struc- active Leach Lake strand of the Garlock fault to break. tures. Thus, in paleogeographic coordinates, the Owlshead Mountains have occupied a map area similar to their present area since ca. 14 Ma. Keywords: Death Valley, Mojave, Garlock fault, vertical axis rotation, Structurally the Owlshead block is complexly faulted, but not tectonics. highly extended (Fig. 1). The block is bounded to the east and west by northwest-striking dextral fault systems and to the south and north INTRODUCTION by east- to east-northeast±striking sinistral faults (Fig. 1). Aside from The Northeast Mojave±southern Death Valley region in eastern the Wingate Wash fault, all of these faults have well-documented slips (Fig. 1) is one of the best-exposed transtensional systems in of 10 km or more. Our recent work on the Wingate Wash fault system the world. Here the combination of low precipitation and active de- (e.g., Golding, 2000; Golding and Pavlis, 2000; Guest, 2000, 2001) formation facilitates detailed studies of progressive transtensional, ex- indicates that this fault has accommodated 8±15 km of sinistral slip. tensional, and transrotational deformation. The large database for the region means that there is a remarkably complete geologic history for the area, and researchers debate events on time scales of Ͻ1 m.y. Northeast Mojave Block Despite this large database, there is still no consensus on many fun- The Northeast Mojave block is composed of a Mesozoic intrusive damental questions regarding the tectonic evolution of this system. complex with associated screens of older rock overlain locally by Ter- Most prominent among these are discrepancies in the inferred signi®- tiary volcanic and sedimentary rocks. The crystalline assemblages be- cance of extension versus strike-slip movement and the importance of low the Tertiary nonconformity are similar to the Owlshead block, but transrotation driven by the strike-slip systems at different phases in the also contain extensive exposures of middle Mesozoic ductilely de- evolution of the region (e.g., Serpa and Pavlis, 1996; Snow and Wer- formed intrusive rocks and metamorphosed Triassic±Jurassic volcanic nicke, 2000; Wernicke and Axen, 1988; Wright et al., 1991). rocks (e.g., Schermer et al., 1996; Pavlis et al., 1998; Schermer et al., In this paper we present a model that relates the structural and 2001). The Tertiary cover, however, is markedly different from that of geomorphic development of the Owlshead region in southwestern the Owlshead block in that the Northeast Mojave block contains an Death Valley to post±middle Miocene clockwise transrotation of the early Miocene to late Miocene sedimentary sequence (e.g., Spencer, northeastern Mojave block. 1990; Pavlis et al., 1998; Brady and Troxel, 1999). The key features of the Northeast Mojave block relevant to Neogene reconstruction are REGIONAL GEOLOGY AND PREVIOUS WORK four subparallel, approximately east-striking sinistral faults (Fig. 1) that Owlshead Mountains and Southern Panamint Range cut the Miocene basin deposits and produce the present topographic The Owlshead Mountains (hereafter referred to as the Owlshead grain (e.g., Pavlis et al., 1998; Schermer et al., 1996). The northernmost block) cover ϳ1000 km2 in the southwestern corner of Death Valley of these faults is the Garlock fault, which has a well-documented Neo- National Park (Fig. 1). The Owlshead block is composed predomi- gene offset of ϳ64 km (Monastero et al., 1997). The Garlock fault nantly of Mesozoic granitic and metamorphic rocks (Calzia, 1974; Da- merges eastward into an intersection with the dextral Death Valley fault

᭧ 2003 Geological Society of America. For permission to copy, contact Copyright Permissions, GSA, or [email protected]. Geology; June 2003; v. 31; no. 6; p. 553±556; 2 ®gures. 553

Downloaded from https://pubs.geoscienceworld.org/gsa/geology/article-pdf/31/6/553/3527496/i0091-7613-31-6-553.pdf by California Geological Survey, 19774 on 20 July 2019 Ross et al., 1989; Schelle and GruÈnthal, 1996; Schermer et al., 1996) as having undergone signi®cant late Cenozoic vertical-axis clockwise rotation. The vertical axis rotation is estimated at ϳ45Њ (Pavlis et al., 1998).

PREVIOUS MODELS Numerous models for the (Luyendyk et al., 1980; Carter et al., 1987; Golombeck and Brown, 1988; Luyendyk, 1991; Pavlis et al., 1998; Ron et al., 2000; Ross et al., 1989; Schelle and GruÈnthal, 1996; Schermer et al., 1996) argue for signi®cant clockwise rotation of the Northeast Mojave block, but transrotation to the north, in the Death Valley region, is generally ignored or downplayed because of the predominance of extensional structures. The model of Carter et al. (1987) suggested dextral shear north of the Garlock fault as a result of clockwise rotation in the Northeast Mojave, but did not go into detail. Serpa and Pavlis (1996) and Snow and Wernicke (2000) in- cluded transrotation of the Garlock system, but these reconstructions disagree markedly in the Owlshead Mountains part of the system. Spe- ci®cally, Snow and Wernicke's (2000) interpretation restored the Owls- head block to a series of thin slivers Ͻ5 km wide ca. 8 Ma, whereas Serpa and Pavlis (1996) restored the block through a combination of transrotation and extension that produced a restored Owlshead block Figure 1. Segment of Trona sheet geologic map showing Owlshead block, southern Death Valley, and Northeast Mojave block. WWFZÐ only slightly smaller than the present area. Both of these efforts lack Wingate Wash fault zone, BMFÐBrown Mountain fault, OLFÐOwl basic information about the Owlshead block, particularly the structures Lake fault, DVFZÐDeath Valley fault zone, MSSÐMule Springs that separate that block from the Panamint block. In light of our recent strand, LLSÐLeach Lake strand, DWLFÐDrink Water Lake fault, work in the Wingate Wash region (Golding, 2000; Guest, 2000, 2001; FIFÐFort Irwin fault, CCFÐCoyote Canyon fault, TMFÐTiefort Mountain fault. Serpa and Pavlis, 1996), it is clear that neither of these previous models is consistent with the geology of the Owlshead block. In Figure 2, we present a new, alternative reconstruction for this region. system, producing a transpressional interaction along the east side of the (Brady, 1986a, 1986b; Brady and Troxel, NEW MODEL 1999; Spencer, 1990). In this model the Owlshead and southern Panamint blocks are The remaining three sinistral faults de®ne a series of east-west± hypothesized to have undergone sinistral transtension in response to a oriented fault-bounded blocks, described by many (Luyendyk, 1991; clockwise rotation of their southern con®ning boundary (Garlock fault MacConnell et al., 1994; MacFadden et al., 1990; Pavlis et al., 1998; zone). This rotation of the Garlock fault zone is assumed to result from

Figure 2. See discussion in text. RTRÐRadio Tower Range, SOMÐSouthern Owlshead Mountains, WWFZÐWingate Wash fault zone, BMFÐ Brown Mountain fault, OLFÐOwl Lake fault, GFÐGarlock fault, MSSÐMule Springs strand, LLZÐLeach Lake fault zone, SDVFZÐSouthern Death Valley fault zone.

554 GEOLOGY, June 2003

Downloaded from https://pubs.geoscienceworld.org/gsa/geology/article-pdf/31/6/553/3527496/i0091-7613-31-6-553.pdf by California Geological Survey, 19774 on 20 July 2019 large magnitude (35Њ or more), vertical-axis, domino-style, clockwise to the south, along the arc of rotation, from its prerotation position. To rotation of the crustal slivers that compose the Northeast Mojave block accommodate the 23Њ rotation of the Garlock fault, the Owlshead block (Luyendyk et al., 1980; Carter et al., 1987; Golombeck and Brown, increases in area by ϳ137 km2 from its prerotation size (Fig. 2C). The 1988; Luyendyk, 1991; Pavlis et al., 1998; Ron et al., 2000; Ross et current area covered by the Owlshead block is ϳ1000 km2;onthe al., 1989; Schelle and GruÈnthal, 1996; Schermer et al., 1996). Fur- basis of this current area, we can estimate the area covered by the thermore, we hypothesize that rotation of the eastern segment of the Owlshead block prior to rotation as ϳ863 km2. Increasing the prero- Garlock fault out of the regional stress ®eld established conditions in tation area by 137 km2 requires ϳ16% extension of the Owlshead which sinistral shear related to differential deformation between the block. This value differs from the calculated extension value in re- Mojave block and the Basin and Range is transferred onto optimally stored-area balanced cross section by ϳ3%, which is well within the oriented faults to the north of the eastern Garlock fault (Ron et al., error of this analysis (Fig. 2). 2000). Two such optimally oriented fault zones are the Owl Lake fault and the Wingate Wash fault zone, both of which have been shown to IMPLICATIONS be more recently active than the possibly abandoned northernmost This reconstruction has signi®cant implications for the Cenozoic strand of the eastern Garlock fault (Mule Springs strand) (McGill, structural history of the Death Valley region: (1) Vertical-axis clock- 1998a; McGill and Sieh, 1991). The southern strand of the eastern wise rotation of the Northeast Mojave block results in the relative Garlock fault (Leach Lake strand) is still active, but its continued mo- southward shift of the southern restraining boundary of the Owlshead tion is interpreted as the northernmost edge of the northeast Mojave Mountains. This shift is accommodated by southeast-directed extension transrotational block (Fig. 2). of the Owlshead Mountains. The implication here is that the Owlshead This model is based on a reconstruction that uses the pre±14 Ma and southern Panamint region is an accommodation zone that buffers erosion surface beneath the Miocene volcanic pile in the southern Pan- differential motion between the Basin and Range and northeast Mojave. amint Range and Owlshead Mountains (Davis, 1982; Davis and Fleck, (2) If this clockwise rotation started in the early Miocene, then we 1977; Golding, 2000; Guest, 2000, 2001) as a constraint on restored would have to infer sinistral shear in the region between the northeast map area and cross-section length. The model also assumes that slip- Mojave and the Owlshead Mountains prior to the initiation of the Gar- rate estimates on the Owl Lake fault zone and Garlock fault (McGill, lock fault. This, in turn, would provide a zone of weakness into which 1998a, 1998b; McGill and Sieh, 1991, 1993) are constant at multi- the Garlock fault propagated with the onset of Basin and Range ex- million year time scales. Furthermore, an assumption has to be made tension to the north of the Mojave block. A further implication of about total slip on the sinistral strike-slip Owl Lake fault, because we clockwise rotation in the Northeastern Mojave block is the possibility need to remove deformation along this fault so that a restored north- that rotation could account for a signi®cant part of the offset on the south cross section across the Owlshead block and southern Panamint Garlock fault, depending on the location of the axis of rotation. (3) Range can be constructed. The total slip estimate we use is based on Rotation of the Garlock fault resulted in the initiation of the Owl Lake two pieces of evidence. (1) Geophysical data (gravity and magnetic fault and probably accounts for sinistral shear observed in the Wingate anomaly maps) indicate a magnetic anomaly that is offset ϳ7.5 km by Wash region. This statement is consistent with the Ron et al. (2000) the Owl Lake fault (Jachens and Calzia, 1998). (2) The Mule Springs model for the propagation of new fault strands when the old fault strand strand of the Garlock fault is probably offset by slip on the Owl Lake has been rotated ϳ25Њ from its optimal position in the regional stress fault and has no recent rupture along its trace (McGill and Sieh, 1991). ®eld by block rotation. This model implies that continued differential deformation between the Basin and Range and the Northeast Mojave When the Mule Springs strand is restored to a position where it lines block may be accommodated by slip on the Owl Lake fault and Win- up with the western trace of the Garlock fault, it restores 7.5 km of gate Wash fault zone. (4) In contrast, dextral slip on the Brown Moun- slip on the Owl Lake fault and agrees nicely with the estimate made tain fault may result in counterclockwise rotation of the Owlshead from the Jachens and Calzia (1998) magnetic anomaly map. Further- block, thereby rotating the Owl Lake fault out of the optimum orien- more, there are sinistrally offset Tertiary volcanic rocks and fanglom- tation for accommodating strain accumulating along the western Gar- erates on either side of this fault that, from map patterns, appear to lock fault. Slip on the Brown Mountain fault has the additional con- record displacement along the Owl Lake fault that is consistent with sequence of jamming the Garlock fault with the southwest corner of the 7.5 km displacement mentioned previously. the Owlshead block, thereby forcing the Leach Lake fault to break. (5) With these assumptions in mind, the Miocene basal unconformity Normal faults in the southern Panamint block are related to northwest- and the slip-rate estimates presented for the Garlock fault and Owl southeast±directed extension in the hanging wall of the fault that sep- Lake fault (McGill, 1998a, 1998b; McGill and Sieh, 1991, 1993) can arates the Panamint block from the Owlshead block. be used to retrodeform the Owlshead block and southern Panamint block, thereby restoring them to their 14±12 Ma positions and shapes CONCLUSIONS (Fig. 2). In the process of restoring deformation in this region, the This reconstruction establishes the importance of the southern major basins in the Owlshead block are closed, and the southern Pan- Panamint±Owlshead accommodation zone in understanding interac- amint block is restored to a position that closes Wingate Wash and tions between the Mojave block and the Basin and Range. Speci®cally, Death Valley. To facilitate the closure of these basins, the eastern Gar- any model that deals with rotation in the northern Mojave can be tested lock fault is retrorotated counterclockwise (straightened) to an orien- by looking to the effect that this rotation should have on crust to the tation that is optimal for a fault that accommodates differential strain north of the Garlock fault. In this case it is clear that clockwise rotation between the Basin and Range and the Mojave block (i.e., sinistral tran- of the northeast Mojave block has resulted in 13%±15% extension in stension carrying Basin and Range particles to the northwest relative the Owlshead Mountains to the north of the Garlock fault. This small- to the ``stable'' Mojave block). magnitude extension is consistent with the regionally extensive expo- The eastern Garlock fault is estimated to have rotated ϳ23Њ±45Њ sure of the pre±14 Ma erosion surface throughout the Owlshead block, clockwise through an arc that pivots at the northwestern corner of the but is inconsistent with Ͼ300% extension inferred for this region by Northeast Mojave block (Luyendyk et al., 1980; Carter et al., 1987; the reconstruction of Snow and Wernicke (2000). Schermer et al., 1996). This is the same pivot point used in this re- This rotation had the additional effect of rotating the Garlock fault construction. This rotation, at 37 km from the pivot point, moves the out of an orientation that is optimal for accommodating sinistral shear southern boundary of the Owlshead block (the Garlock fault) ϳ15 km between the Basin and Range and the Mojave. This condition renders

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Downloaded from https://pubs.geoscienceworld.org/gsa/geology/article-pdf/31/6/553/3527496/i0091-7613-31-6-553.pdf by California Geological Survey, 19774 on 20 July 2019 the eastern segment of the Garlock effectively inactive and requires crustal rotations in southern California: Geological Society of America Bulletin, v. 91, p. 211±217. that any sinistral shear be accumulated on optimally oriented faults like MacConnell, D.F., McCabe, C., Dokka, R.K., and Chu, M., 1994, Paleomagnetism and the Owl Lake fault and the Wingate Wash fault zone, a conclusion structural evidence for localized tectonic rotation associated with fault drag in the consistent with observed Quaternary deformation along these northeastern Mojave Desert: Implications for the late Cenozoic evolution of the East- ern California shear zone: Earth and Planetary Science Letters, v. 126, p. 207±216. structures. MacFadden, B.J., Woodburne, M.O., and Opdike, N.D., 1990, Paleomagnetism and Neo- In general, this model suggests that regions dominated by vertical gene clockwise rotation of the northern Cady Mountains, Mojave Desert of southern California: Journal of Geophysical Research, v. 95, p. 4597±4608. axis rotation undergo signi®cant map view shape changes that require McGill, S.F., 1998a, Preliminary slip-rate estimate for the Owl Lake fault, California, in surrounding regions to deform in response. In addition, the faults Calzia, J.P., and Reynolds, R.E., eds., Finding faults in the Mojave: San Bernardino bounding these regions are forced to change orientation, thereby forc- County Museum Association Quarterly, v. 45, p. 84±87. McGill, S.F., 1998b, Summery of Neotectonic slip-rate studies of the Garlock and Owl ing new, optimally oriented faults to break in order to relax regional Lake fault zones, in Calzia, J.P., and Reynolds, R.E., eds., Finding faults in the stresses. This idea is applicable to all regions dominated by strike-slip Mojave: San Bernardino County Museum Association Quarterly, v. 45, p. 88±90. deformation. McGill, S.F., and Sieh, K., 1991, Sur®cial offsets on the central and eastern Garlock fault associated with prehistoric earthquakes: Journal of Geophysical Research, v. 96, p. 21,597±21,621. ACKNOWLEDGMENTS McGill, S.F., and Sieh, K., 1993, Holocene slip rate of the central Garlock fault in south- We thank Joel Lucklow for valuable ®eld assistance. This research was funded by eastern Searles Valley, California: Journal of Geophysical Research, v. 98, National Science Foundation grant EAR-9706233. We also thank Bruce Luyendyk and Matt p. 14,217±14,231. Golombeck for insightful reviews. Monastero, F.C., Sabin, A.E., and Walker, J.D., 1997, Evidence for postearly Miocene initiation of movement on the Garlock fault from offset of the Cudahy Camp For- mation, east-central California: Geology, v. 25, p. 247±250. REFERENCES CITED Pavlis, T., Serpa, L.F., Troxel, T.W., Dean, M., Hartmen, T., and Rodosta, T., 1998, Late Brady, R.H., III, 1986a, Cenozoic geology of the northern Avawatz Mountains in relation Cenozoic deformation in eastern Fort Erwin and its signi®cance for the tectonic to the intersection of the Garlock and Death Valley fault zones, San Bernardino history of the Garlock fault system, in Calzia, J.P., and Reynolds, R.E., eds., Finding County, California [Ph.D. thesis]: Davis, University of California, 292 p. faults in the Mojave: San Bernardino County Museum Association Quarterly, v. 45, Brady, R.H., III, 1986b, Stratigraphy and tectonics of the northern Avawatz Mountains at p. 77±83. the intersection of the Garlock and Death Valley fault zones, San Bernardino County, Ron, H., Beroza, G., and Nur, A., 2000, A mechanical explanation for multiple-fault rupture California, in Troxel, B.W., ed., Quaternary tectonics of southern Death Valley, in the Mojave, in Proceedings, Third Conference on Tectonic problems of the San CaliforniaÐField trip guide: Shoshone, California, Friends of the Pleistocene, Paci®c Andreas fault system, Volume 3: Stanford, Callifornia, Stanford University, p. 12. Cell, p. 1±12. Ross, T.M., Luyendyk, B.P., and Haston, R.B., 1989, Paleomagnetic evidence for Neogene Brady, R.H., III, and Troxel, B.W., 1999, The Miocene Military Canyon Formation: De- clockwise tectonic rotations in the central Mojave Desert, California: Geology, v. 17, pocenter evolution and constraints on lateral faulting, southern Death Valley, Cali- p. 470±473. fornia, in Wright, L.A., and Troxel, B.W., eds., Cenozoic basins of the Death Valley Schelle, H., and GruÈnthal, G., 1996, Modeling of Neogene crustal block rotation: Case region: Geological Society of America Special Paper 333, p. 277±288. study of southeastern California: Tectonics, v. 15, p. 700±710. Calzia, J.P., 1974, Igneous geology of a part of the southern Owlshead Mountains, San Schermer, E.R., Luyendyk, B.P., and Cisowski, S., 1996, Late Cenozoic structure and tec- Bernardino County, California [M.S. thesis]: Los Angeles, University of Southern tonics of the northern Mojave Desert: Tectonics, v. 15, p. 905±932. California, 77 p. Schermer, E.R., Stephens, K.A., and Walker, J.D., 2001, Paleogeographic and tectonic im- Carter, J., Luyendyk, B.P., and Terres, R.R., 1987, Neogene clockwise tectonic rotation of plications of the geology of the Tiefort Mountains, northern Mojave Desert, Cali- the eastern Transverse Ranges, California, suggested by paleomagnetic vectors: Geo- fornia: Geological Society of America Bulletin, v. 113, p. 920±938. logical Society of America Bulletin, v. 98, p. 199±206. Serpa, L.F., and Pavlis, T., 1996, Three-dimensional model of the late Cenozoic history of Davis, G.A., 1982, Structure and geologic history of the Owlshead Mountains, in Troxel, the Death Valley region, southeastern California: Tectonics, v. 15, p. 1113±1128. B.W., and Wright, L.A., eds., Death Valley region ®eld guide: Cypress, Florida, Snow, J.K., and Wernicke, B., 2000, Cenozoic tectonism in the central Basin and Range: National Association of Geology Teachers, p. 66±67. Magnitude, rate, and distribution of upper crustal strain: American Journal of Sci- Davis, G.A., and Fleck, R.J., 1977, Chronology of Miocene volcanic and structural events, ence, v. 300, p. 659±719. central Owlshead Mountains, eastern San Bernardino County, California: Geological Snow, J.K., Asmerom, Y., and Lux, R.L., 1991, Permian±Triassic plutonism and tectonics, Society of America Abstracts with Programs, v. 9, p. 409. Death Valley region, California and Nevada: Geology, v. 19, p. 629±632. Gastil, R.G., DeLisle, M., and Morgan, J.R., 1967, Some effects of progressive metamor- Spencer, J.E., 1990, Late Cenozoic extensional and compressional tectonism in the southern phism on zircons: Geological Society of America Bulletin, v. 78, p. 879±906. and western Avawatz Mountains, southeastern California, in Wernicke, B., ed., Basin Golding, H.R., 2000, Syntectonic volcanism and sedimentation in a transtensional environ- and Range extensional tectonics near the latitude of Las Vegas, Nevada: Geological ment: Late Cenozoic evolution of Wingate Wash, Death Valley [M.S. thesis]: New Society of America Memoir 176, p. 317±333. Orleans, University of New Orleans, 92 p. Wagner, D.L., 1998, Rifted volcano in Wingate Wash, Death Valley region, southeastern Golding, H.R., and Pavlis, T., 2000, Syntectonic volcanism and sedimentation in a tran- California, in Calzia, J.P., and Reynolds, R.E., eds., Finding faults in the Mojave: stensional environment, Wingate Wash, Death Valley: Geological Society of America San Bernardino County Museum Association Quarterly, v. 45, p. 62±65. Abstracts with Programs, v. 32, no. 7, p. A502. Wagner, D.L., and Hsu, E.Y., 1988, Reconnaissance geologic map of parts of the Wingate Golombeck, M.P., and Brown, L.L., 1988, Clockwise rotation of the western Mojave De- Wash, Quail Mountains, and Manly Peak quadrangles, Inyo and San Bernardino sert: Geology, v. 16, p. 126±130. Counties, southeast California: California Division of Mines and Geology, scale 1: Guest, B., 2000, Clockwise rotation of the Northeast Mojave block is accommodated by 62,500. extension in the Owlshead Mountains: A model describing the impact that rotation Wernicke, B., and Axen, G.J., 1988, On the role of isostasy in the evolution of normal of the northeastern Mojave block has had on the position of the Garlock fault, and fault systems: Geology, v. 16, p. 848±851. the Owlshead Mountains, Death Valley, California: Geological Society of America Wright, L.A., Thompson, R.A., Troxel, T.W., Pavlis, T., DeWitt, E.H., Otton, J.K., Ellis, Abstracts with Programs, v. 32, no. 7, p. A507. M.A., Miller, M.G., and Serpa, L.F., 1991, Cenozoic magmatic and tectonic evolution Guest, B., 2001, The geology of the northwestern Owlshead Mountains, Death Valley, of the east-central Death Valley region, California, in Walawender, M.J., and Hanan, California [M.S. thesis]: New Orleans, University of New Orleans, 68 p. B.B., eds., Geological excursions in southern California and Mexico: Boulder, Col- Jachens, R.C., and Calzia, J.P., 1998, A geophysical analysis of the Garlock fault, in Reyn- orado, Geological Society of America Field Trip Guidebook: p. 93±127. olds, R.E., and Calzia, J.P., eds., Finding faults in the Mojave: San Bernardino County Museum Association Quarterly, v. 45, p. 36±41. Manuscript received 7 November 2002 Luyendyk, B.P., 1991, A model for Neogene crustal rotations, transtension, and transpres- Revised manuscript received 12 February 2003 sion in southern California: Geological Society of America Bulletin, v. 103, Manuscript accepted 17 February 2003 p. 1528±1536. Luyendyk, B.P., Kamerling, M.J., and Terres, R., 1980, Geometric model for Neogene Printed in USA

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