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Distribution of Neogene extension and strike slip

in the Death Valley region, California-Nevada,

with implications for palinspastic reconstruction and models of normal faulting

Byrdie Renik

Submitted in partial fulfillment of the

Requirements for the degree

of Doctor of Philosophy

in the Graduate School of Arts and Sciences

COLUMBIA UNIVERSITY

2010

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UMI Number: 3401053 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion.

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? 2009

Byrdie Renik

ABSTRACT

Distribution of Neogene extension and strike slip in the Death Valley region, California-Nevada, with implications for palinspastic reconstruction and models of normal faulting

Byrdie Renik

The Death Valley area of California and Nevada has served as a testing ground for ideas about extensional and strike-slip tectonics. Widely adopted concepts that have been refined there include, among others, active low-angle normal faulting and the rolling hinge model. Active low-angle normal faulting offers a way to accommodate extreme amounts of extension but remains a rock-mechanical paradox. The rolling hinge model offers a potential solution, as does domino-style normal faulting. Despite decades of research in Death Valley, the applicability of these models there is still contested.

This dissertation evaluates evidence for each, focusing on central Death Valley and its bounding strike-slip faults, the Furnace Creek and Sheephead fault zones. Chapter 1 provides an introduction. Chapter 2 reevaluates the single most offset piercing point: the Eagle Mountain Formation. The original, alluvial fan interpretation of these deposits implied ~104 km of tectonic transport from their source. New sedimentological and stratigraphic data suggest that they are fluvial and do not constrain tectonic transport. Chapter 3 proposes a hypothesis for the distribution of dextral offset along the Furnace Creek fault zone, with an along-strike maximum of ~50 km. The results imply that total Neogene tectonic transport along the corridor defined by the Eagle Mountain Formation was ~68 rather than ~104 km. Furnace Creek fault geometry is inconsistent with an originally continuous, regional detachment. Chapter 4 presents new mapping and

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structural analysis of the Sheephead fault zone, interpreted as a bookshelf-style structure with dextral offset between a few kilometers and ~18.5 ± 8.5 km. The data favor modest

over extreme extension, and cast doubt on the rolling hinge interpretation of a throughgoing detachment. Appendix 1 provides additional discussion of the Eagle Mountain Formation. Appendix 2 summarizes preliminary results from an in-progress, thermochronological test of the rolling hinge model. Appendix 3 suggests subjects for future research.

Additional implications of this dissertation pertain to pull-apart deformation in Death Valley, displacement and displacement-rate budgets of the Eastern California Shear Zone, palinspastic reconstruction of the Cordilleran fold and thrust belt, geometrical quantification of displacement in bookshelf fault systems, and factors favoring bookshelf-style deformation.

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TABLE OF CONTENTS List of figures and tables (vi)

Acknowledgments .............................................................................................................. x Chapter 1: Introduction (1)

1. Motivation (1)

2. Concept and contents of the dissertation (3)

References .................................................................................................................... 8 Chapter 2: Re-evaluation of the middle Miocene Eagle Mountain Formation and its

significance as a piercing point for the interpretation of extreme extension across the Death Valley region, California, U.S.A. (14)

Abstract (14)

1. Introduction (15)

2. Geological setting (18)

3. Description of the Eagle Mountain Formation (19)

3.1 Basal unconformity ........................................................................................ 22 3.2 Facies ............................................................................................................. 24 3.3 Stratigraphic architecture ............................................................................... 28 3.4 Patterns of grain-size variation ...................................................................... 29 4. Paleoenvironmental interpretation . (30)

5. Significance of stratigraphic discontinuities (32)

6. Comparison with previous interpretations (33)

6.1 Disorganized and parallel-stratified deposits (34)

6.2 Clast angularity (34)

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6.3 Cross-stratification ......................................................................................... 35 6.4 Abundance of channels . (36)

6.5 Grain-size trends ............................................................................................ 36 7. Distance and gradient of sediment transport . (37)

8. Local deformation (40)

9. Conclusions (41)

Acknowledgments (44)

References (44)

Figure captions ........................................................................................................... 55 Figures ........................................................................................................................ 62 Chapter 3: A new hypothesis for the amount and distribution of dextral displacement along the Fish Lake Valley-Northern Death Valley-Furnace Creek fault zone, California-

Nevada (79)

Abstract (79)

1. Introduction (80)

2. Geologic setting (82)

3. Magnitude and distribution of dextral displacement (84)

3.1 Slate Canyon-Dry Creek thrust fault (84)

3.2 Quartz monzonite of Beer Creek (85)

3.3 Grapevine-Last Chance thrust fault (86)

3.4 Box fold (86)

3.5 Schwaub Peak-Panamint(-Lemoigne?) thrust fault (91)

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3.5.1 Correlation of the Schwaub Peak and Panamint thrusts ....................... 91 3.5.2 Interpretations of the Lemoigne thrust .. (93)

3.6 Clery-western Black Mountains thrust system .............................................. 95 3.7 Mesoproterozoic-Paleozoic stratigraphic markers (97)

4. Timing of faulting (98)

4.1 Pre-Neogene activity (98)

4.2 Neogene activity (99)

5. Displacement rates (101)

6. Relationship to associated extension ................................................................... 102 7. Implications for displacement between the Cottonwood Mountains and the Resting Spring-Nopah Range (104)

7.1 Magnitude and direction (104)

7.2 Partitioning of displacement between the Death Valley-Furnace Creek Wash and Amargosa Valley areas (108)

7.3 Comparison with previous interpretations ................................................... 109 7.4 Implications for the Eastern California Shear Zone .................................... 111 7.5 Mechanisms of extension ............................................................................. 112 8. Conclusions .......................................................................................................... 114 References ................................................................................................................ 115 Figure and table captions ......................................................................................... 128 Figures and tables .................................................................................................... 134 Chapter 4: The Sheephead fault zone and its role in bounding Neogene extension and magmatism in the Death Valley area, California .. (146)

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1. Introduction (147)

2. Overview of the Black Mountains, Greenwater Range, and Dublin Hills ........... 150 3. The Sheephead fault zone at Sheephead Pass (152)

3.1 Interpretation (154)

3.2 Origin of bookshelf faulting at Sheephead Pass (156)

4. Westward continuation of the Sheephead fault zone (157)

5. Eastward continuation of the Sheephead fault zone (158)

6. Timing of activity ................................................................................................ 162 7. Magnitude of displacement . (163)

8. Estimates of crustal extension (167)

9. Implications for the Amargosa fault (168)

10. Implications for the pull-apart model (172)

11. Conclusions ........................................................................................................ 172 References ................................................................................................................ 173 Figure and table captions ......................................................................................... 184 Figures and tables .................................................................................................... 191 Appendix 1: Stratigraphic discontinuities and deformation in the Eagle Mountain Formation .. (213)

1. Significance of stratigraphic discontinuities (213)

2. Conglomerate dikes (214)

2.1 Overview (214)

2.2 Origin of the dikes (215)

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3.1 Overview (216)

3.2 The most prominent faults ........................................................................... 217 3.3 Anomalous compressional structures . (218)

4. Lateral changes in bedding strike ........................................................................ 218 References ................................................................................................................ 219 Figure and table captions ......................................................................................... 220 Figures and tables .................................................................................................... 222 Appendix 2: A thermochronological test of the rolling hinge model as applied to the Black Mountains, California (227)

References ................................................................................................................ 231 Figure captions ......................................................................................................... 231 Figures ...................................................................................................................... 234 Appendix 3: Subjects for future research .. (236)

References (237)

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LIST OF FIGURES AND TABLES Chapter 2

Figure 1 Physiographic map of Death Valley region ............................................. 62 Figure 2 Eagle Mountain viewed from the southeast ............................................. 63 Figure 3 Maps of middle Miocene Eagle Mountain Formation at Eagle

Mountain (64)

Figure 4 Middle fluvial-lacustrine interval of Eagle Mountain Formation ............ 66 Figure 5 Stratigraphic sections through Eagle Mountain Formation at Eagle

Mountain (67)

Figure 6 Paleocurrents from Eagle Mountain Formation at Eagle Mountain (70)

Figure 7 Conceptual cross section of Eagle Mountain Formation ......................... 72 Figure 8 Distribution of facies at measured sections above the basal breccia-

sandstone interval (73)

Figure 9 Photographs of selected facies (74)

Figure 10 Large channel with ~ 14 m of relief (76)

Figure 11 Cross cutting erosional surfaces ~ 10 m northeast of section 5 (77)

Figure 12 Detail of section 7 .................................................................................... 78 Chapter 3

Figure 1 Location of the Fish Lake Valley-Northern Death Valley-Furnace Creek

fault zone (134)

Figure 2 Contrasting conceptual models .............................................................. 135 Figure 3 Selected normal and strike-slip faults in the vicinity of the Furnace Creek

fault zone (136)

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Figure 4 Map of markers inferred to predate faulting; restored cross-section of contractile structures in Cottonwood and northern Panamint

Mountains .............................................................................................. 137 Figure 5 Location of total offset estimates ........................................................... 139 Figure 6 Displacement and displacement rate over time and along strike ........... 140 Figure 7 Distances used in calculating displacement across Death Valley .......... 142 Figure 8 Schematic geometrical relationships at Furnace Creek horsetail splay in

Amargosa Valley (143)

Table 1 Timing of offsets and implied average displacement rates .................... 144 Table 2 Estimates of displacement between Cottonwood Mountains and Resting

Spring-Nopah Range (145)

Chapter 4

Figure 1 Location map and generalized geology of central Death Valley plutonic-

volcanic field (191)

Figure 2 Contrasting conceptual models .............................................................. 192 Figure 3 Southern boundary of central Death Valley plutonic-volcanic field at

Sheephead Pass (193)

Figure 4 Mesoproterozoic-Cambrian stratigraphy exposed in central Death Valley

plutonic-volcanic field (194)

Figure 5 Volcanic stratigraphy at Sheephead Mountain ...................................... 195 Figure 6 Map of Sheephead fault zone at Sheephead Pass .................................. 196 Figure 7 Fault dips versus kinematic indicator rakes for measured planes at

Sheephead Pass (199)

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Figure 8 Rose diagrams of fault orientations, sorted by motion sense, at Sheephead Pass (200)

Figure 9 Possible interpretations of motion sense at Sheephead Pass ................. 201 Figure 10 Explanations for bookshelf style ............................................................ 202 Figure 11 Generalized map of Virgin Spring area ................................................. 203 Figure 12 Map of fault zone in Amargosa Valley .................................................. 204 Figure 13 Fault dips versus kinematic indicator rakes for measured planes in

Amargosa Valley (206)

Figure 14 Rose diagrams of fault orientations, sorted by motion sense, in Amargosa Valley (207)

Figure 15 Bookshelf analogy ................................................................................. 208 Figure 16 Hypothetical relationships between the Sheephead fault zone and the

Amargosa fault (209)

Figure 17 Basins, ranges, and major Neogene dextral faults in central and southern Death Valley .......................................................................................... 210 Table 1

Volcanic stratigraphy at Sheephead Mountain and Sheephead Pass ..... 211 Table 2

Values involved in maximum displacement calculation ....................... 212 Appendix 1

Figure 1 Clast counts for dikes 1-3 ...................................................................... 222 Figure 2 Evidence for organization within dike fill ............................................. 223 Figure 3 Measurements of fault attitudes ............................................................. 224 Table 1

Conglomerate dikes ............................................................................... 225 Table 2 Faults influencing perception of stratigraphic thickness .. (226)

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Appendix 2

Figure 1 Rolling hinge interpretation and gross geology of the Black Mountains, with published mineral cooling ages from basement rocks (234)

Figure 2 Preliminary 40Ar/39Ar results (235)

ACKNOWLEDGMENTS Thanks to everyone who helped me produce this dissertation. It has been a pleasure

to work with the members of my advisory committee. Nick Christie-Blick has been enthusiastic, available, open-minded, creative, insightful, and supportive – an exceptional mentor. I especially appreciate his emphasis on teaching me to think critically, and his respect for my ideas and research priorities. Mark Anders has taught me a great deal about structural geology and field techniques, continually emphasizing how to evaluate evidence carefully and uphold scientific practices rigorously. Sidney Hemming has guided me through geo- and thermochronological projects, generously accommodating them into busy labs and teaching me to approach them strategically. Peter Kelemen helped me set research directions early on and has broadened my understanding of geodynamics. The external members of my defense committee, Donna Shillington and Nadine McQuarrie, provided very useful evaluations of the work.

Lauren Wright and Bennie Troxel deserve special thanks. Through outcrop excursions and Shoshone dinners, as well as visits in State College and Napa, Lauren and Bennie have imparted invaluable knowledge and perspective about the geology of Death Valley, and enriched my experience of working there. Bennie, Lauren, and Nathan Niemi contributed directly to the Eagle Mountain project (Chapter 2), and Lauren was also instrumental in the Sheephead fault zone project (Chapter 4).

Several people helped my field seasons to run smoothly. Thanks to field assistants Shahla Ali, Rafael Almeida, Dalia Bach, Rob Bialas, Louisa Bradtmiller, Jessie Cherry, Martin Collier, Bella Gordon, Deepu Makkar, Si Mayer, Abby Swann, Lida Teneva, Zach Walke, and Rob Wallace. The SHEAR facility provided me with accommodations,

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storage, and the opportunity to interact with a wide range of geologists; particular thanks are due to Darrel Cowan, Marli Miller, Terry Pavlis, and Laura Serpa. Thanks also to

Ganqing Jiang; the communities of Shoshone and China Ranch, California; and Death Valley National Park.

I would like to acknowledge, among the many people at Lamont who have helped me during graduate school, Marissa Tremblay, Lila Neiswanger, Chris Scholz, Chris Walker, Rafael Almeida, Paul Olsen, Roger Buck, Nano Seeber, Geoff Abers, Lynn Sykes, Jim Gaherty, Rob Bialas, Chad Holmes, Martin Collier, Don Penman, Su-chin Chang, Stephen Cox, Jean Hanley, Tom Protus, Bonnie Bonkowski, Dana Miller, Mary Russell, Kathryn Kennedy, Stacey Vassallo, Karen Benedetto, Mia Leo, Carol Mountain, Missy Pinckert, Jean Leote, Bree Burns, Betty Hiscock, Amanda Bielskas, Miriam Colwell, Sherry Wei, Lisa Fish, Mary Ann Brueckner, Rob Kakascik, Mahdad Parsi, Phil Fitzpatrick, Doug Shearer, and Bob Bookbinder.

The research was funded by the National Science Foundation, the Petroleum Research Fund of the American Chemical Society, ExxonMobil, the Geological Society of America, the American Association of Petroleum Geologists, and the Department of Earth and Environmental Sciences at Columbia University.

Many thanks to my family and friends for their love and support.

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1 CHAPTER 1 Introduction

1. Motivation The Death Valley area of eastern California and western Nevada has served as a testing ground for ideas about extensional and strike-slip tectonics. Situated in both the Basin and Range Province and the Eastern California Shear Zone, it has been extended and dextrally sheared in a northwest direction during Neogene time, arguably to as extreme a degree as anywhere in those tectonic domains (e.g., Stewart, 1983; Wernicke et al., 1988; Stevens et al., 1991; Snow and Wernicke, 2000; McQuarrie and Wernicke, 2005). Widely adopted concepts that have been developed or refined there include pull-apart basins, intracontinental transform faulting, “chaos” deformation, active low-angle normal faulting (extensional detachment faulting), the rolling hinge model, synextensional folding about extension-parallel axes, as well as novel approaches to palinspastic reconstruction as a method (e.g., Noble, 1941; Burchfiel and Stewart, 1966; Davis and Burchfiel, 1973; Wright and Troxel, 1973; Stewart, 1983; Hamilton, 1988; Wernicke and Axen, 1988; Wernicke et al., 1988; Snow and Wernicke, 1989, 2000; Holm et al., 1992; Wernicke, 1992; Mancktelow and Pavlis, 1994).

Active low-angle normal faulting – inferred from observations of low fault dips and inferences of extreme amounts of extension – presents a paradox. Rock mechanical theory and experiments indicate that typical rock friction should prevent failure on normal faults dipping < ~25-30o, except in specific circumstances (e.g., Axen, 2004, and references therein). According to Wernicke et al. (1988), the widespread interpretation of

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2 extensional detachment faulting with associated extreme extension therefore indicates that “a major geologic revolution has fundamentally changed how geologists view

extension of the Earth’s lithosphere, based principally on Basin and Range field studies” (p. 1756). In the absence of a general mechanical explanation, however, the paradox remains unresolved.

The rolling hinge model offers a way to explain field observations of continuous detachment faults that is consistent with rock-mechanical understanding to date (e.g., Spencer, 1984; Buck, 1988; Hamilton, 1988; Wernicke and Axen, 1988; Wernicke, 1992; Axen and Bartley, 1997). The model stipulates a detachment flexure that migrates in the direction of hangingwall transport, coordinated with a migrating locus of extension and exhumation. As the flexure moves, a back-tilted, inactive portion of the system is left behind it. Activity continues to occur on its front side, where hinges create moderate to high dips through the brittle field. Successive splays fire from in front of the flexure, slicing off fragments of the hanging wall and all ultimately rooting in the single detachment. The splays and the hangingwall slices are back-tilted and stranded as the flexure passes.

The alternative to these models is moderate- or high-angle faulting, potentially in the domino style (e.g., Proffett, 1977). In this configuration, faults continue to tilt after they become inactive, as younger faults crosscut them. Extension is distributed across a series of discrete fault systems of varied dip and age. There is no originally continuous, basal fault in the brittle field. Various patterns of timing are permissible.

Despite decades of research in Death Valley, the relative applicability of these models there is still contested. All three have been viewed as consistent with and/or required by

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3 available evidence for Neogene extension: low-angle faulting (e.g., Wright and Troxel, 1973; Stewart, 1983; Wernicke et al., 1988), the rolling hinge (e.g., Hamilton, 1988;

Holm, et al., 1992; Keener et al., 1993; Snow and Lux, 1999; Snow and Wernicke, 2000; Niemi, 2001), and domino faulting (e.g., Miller, 1991; Keener et al., 1993; Topping, 2003). A related question is the role of strike slip versus extension in producing features and displacements documented in the area, e.g., the pull-apart versus supradetachment or other extensional style of basin development (e.g., Wright et al., 1991; Serpa and Pavlis, 1996; Prave and McMackin, 1999; Miller and Pavlis, 2005). Because of the influence of Death Valley as a type locality, and because of lingering theoretical uncertainties – how can the low-angle normal fault paradox be resolved? what favors the development of rolling hinges, and how do the factors differ between continental and mid-ocean ridge settings? how is diffuse plate-boundary deformation distributed, and how can it be distinguished from the effects of intraplate forcings? – the geology there continues to deserve scrutiny.

2. Concept and contents of the dissertation

This dissertation aims to evaluate evidence for the various models of normal faulting in the Death Valley region. Particular emphasis is placed on the hypotheses that extension has been extreme in magnitude, and that a single, continuous detachment was originally present to accommodate it. The geographic focus is the central, most extended portion of Death Valley, including its strike-slip fault boundaries to the north and south. This area is rhomb-shaped and known as the central Death Valley plutonic-volcanic field (e.g., Wright et al., 1981, 1991; Serpa and Pavlis, 1996). It presents a geological contrast

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4 with the surrounding ranges. Its distinctive characteristics include widespread exposure of ductilely deformed midcrustal rock, scarcity of pre-extensional sedimentary cover,

abundance of synkinematic igneous rocks, and pervasive, “chaos”-style brittle

deformation. The northern and southern boundaries are, respectively, the Fish Lake Valley-Northern Death Valley-Furnace Creek fault zone (herein called the Furnace Creek fault zone for ease of reference) and the Sheephead fault zone.

Chapter 2 reevaluates the middle Miocene Eagle Mountain Formation, a piercing point considered to provide “some of the strongest direct evidence for major Tertiary displacements” (Snow and Wernicke, 2000, p. 662). That view is based on the interpretation that distinctive clasts in the formation accumulated in an alluvial fan setting and therefore within ~10-20 km of their source, which is now located across Death Valley (Niemi et al., 2001). This implies ~104 km of tectonic transport after deposition, (post-~11 Ma) along a corridor located at the northern margin of the central Death Valley plutonic-volcanic field (Niemi et al., 2001). The transport therefore involves coordinated displacements on normal faults and the dextral Furnace Creek fault zone. The “extreme extension” inferred (Niemi et al., 2001, p. 436) – equivalent to a change in width by a factor of ~4-5 – depends directly upon the distinctive clasts having accumulated at an alluvial fan. New sedimentological and stratigraphic evidence, however, indicates that they were instead deposited in a river system. This means that the amounts of sedimentary versus tectonic transport cannot be discriminated. The implications are that the deposits (1) do not constrain the magnitude of extension or strike slip on the Furnace Creek fault zone, and (2) do not, beyond general inferences from discordance and the syn- or post-depositional character of deformation, precisely bracket the timing of

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Distribution of Neogene extension and strike slip

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