AN ABSTRACT OF THE THESIS OF F. Michael DeDen for the degree of Master of Science in Geology presented on May 27, 1987. Title: Stratigraphy, Depositional Environments, and Diagenesis of the Devonian Simonson and Guilmette Formations in the White Pine, Egan, and Schell Creek Ranges, White Pine County, Nevada Abstract approved:Redacted fOr privacy J. Johnson The Devonian Simonson and Guilmette Formations provide examples of Cordilleran miogeosynclinal inner and middle shelf carbonate deposition that act in response to changes in eustasy, sedimentation, and tectonics. The Simonson Dolomite consists of four members that collectively record three distinct transgressive-regressive cycles. The Coarse Crystalline dolomudstone lithofacies represents restricted upper intertidal to supratidal sedimentation deposited on a distally steepened carbonate ramp. Evolution of the Cordilleran shelf occurred concurrent with deposition of the Lower Alternating cryptalgal dolomudstone lithofacies. A depositional rimmed margin developed recording lagoonal deposition, in the form of upward-shallowing sequences, across the entire Middle Devonian shelf. A continued relative sea-level rise is represented by the lower intertidal to subtidal stromatoporoidal biostromal bank buildups of the Simonson Brown Cliff Member. A relative sea-level fall is recorded by the intertidal to supratidal Upper Alternating dolomud-wackestone lithofacies. Four lithofacies and nine subfacies are differentiated for the Guilmette Formation, representing a broad spectrum of shallow subtidal to intertidal environments. Thick buildups of primarily wackestone and packstone lithofacies accumulated in response to a continued relative sea-level rise. The extensive lateral growth of stromatoporoidal biostromal bank buildups formed under open-marine conditions while more restricted lagoonal environments dominated the inner shelf. Acting in response to initial Antler orogenic foreland effects and in concert with a continuing rise of sea-level, the Guilmette lithotope was eliminated in the Late Devonian along with the Cordilleran depositional rimmed margin. Diagenetic fabric relationships observed in the Simonson and Guilmette reveal a complex history beginning with the early-submarine cementation of aragonite and/or high-Mg calcite. Neomorphic processes followed and resulted in the stabilization to low-Mg calcite. Diagenesis continued in the deep subsurface and included silica cementation and replacement events that both predated and act concurrently with pressure-solution stylolitization and dolomitization. Late diagenetic silicification postdated both burial dolomitization and secondary porosity evolution. Calcite pore and fracture-filling cementation postdated all diagenetic events. Diagenetic textures reflect deep-burial processes rather than the original depositional environment. Reservoir qualities have been enhanced by late-diagenetic dolomitization producing secondary intercrystalline porosity within dolomitic Guilmette horizons and especially in the Simonson Coarse Crystalline Member. Stratigraphy, Depositional Environments, and Diagenesis of the Devonian Simonson and Guilmette Formations in the White Pine, Egan, and Schell Creek Ranges, White Pine County, Nevada by F. Michael DeDen A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Master of Science Completed May 27, 1987 Commencement June 1988 APPROVED: Redacted for privacy Profes or f Geology, in c r e of major Redacted for privacy Chai(rmann of the Departm n f Geology Redacted for privacy Dean of the Gradu School d Date thesis is presented May 27, 1987 ACKNOWLEDGMENTS I would first like to thank Dr. J. G. Johnson for his constant willingness to help me throughout the course of the project. His wealth of knowledge, honesty, and method of thought created a pleasant atmosphere for learning. His critical and prompt review of the manuscript is appreciated as well. Financial support was provided by Amerada Hess, Amoco, Consolidated Natural Gas, and Marathon petroleum companies. Conoco Incorporated provided a technical service by supplying porosity and permeability data. Additional field support was awarded through departmental Chevron Field Scholarships, for the summers of 1985 and 1986. The following specialists are acknowledged for their fossil identifications and age determinations: Dr. J. G. Johnson (brachiopods), Claudia Regier (for preparing conodonts), Dr. Gilbert Klapper, University of Iowa (conodonts), Dr. W. A. Oliver, U. S. National Museum (corals), and Dr. Jacques Poncet, Universite de Caen, France (algae). Special thanks goes to Susan Ivy for her invaluable help in the field measuring section and for providing both moral support and encouragement throughout the completion of the thesis. Gratitude is also expressed to Jill Bird for helping me in the field during the summer of 1986. More importantly, Susan and Jill helped me through the bad times, as well as the good times of which there were many more. Final appreciation is expressed to my parents for their moral and financial support, without which this thesis could not have been completed. Lastly, thanks goes to all of the many friends that I met here at 0. S. U., who made life so much more enjoyable. TABLE OF CONTENTS INTRODUCTION 1 Purpose 1 Location and Accessibility 3 Previous Work 3 Methods of Investigation 7 Regional Geologic History 9 STRATIGRAPHIC NOMENCLATURE AND CORRELATION 14 SIMONSON DOLOMITE 20 Simonson Lithofacies 20 Introduction 20 Coarse Crystalline Member (Dolomudstone Lithofacies) 23 Thickness and Distribution 23 Lithology and Contacts 23 Thin Section Constituents 26 Depositional Environments 27 Sevy and Simonson Quartz Arenites and Quartzose Carbonates 28 Provenance of the Quartz Sands 32 Lower Alternating Member (Dolomudstone Lithofacies) 37 Thickness and Distribution 37 Lithology and Contacts 37 Thin Section Constituents 41 Depositional Environments 42 Brown Cliff Member (Dolowacke-packstone Lithofacies) 50 Thickness and Distribution 50 Lithology and Contacts 50 Thin Section Constituents 52 Depositional Environments 53 Upper Alternating Member (Dolomud-wackestone Lithofacies) 58 Thickness and Distribution 58 Lithology and Contacts 58 Thin Section Constituents 62 Depositional Environments 63 GUILMETTE FORMATION 66 Guilmette Lithofacies 66 Introduction 66 Mudstone Lithofacies 67 Dolomudstone Subfacies 67 Depositional Environments 69 Wackestone Lithofacies 70 Amphipora Wackestone Subfacies 70 Brachiopod and Gastropod Wackestone Subfacies 72 Peloidal Wackestone Subfacies 72 Depositional Environments 73 Packstone Lithofacies 75 Amphipora Packstone Subfacies 75 Bulbous Stromatoporoid Packstone Subfacies 76 Peloidal Packstone Subfacies 77 Brachiopod and Gastropod Packstone Subfacies 80 Crinoidal Dolopackstone Subfacies 81 Depositional Environments 82 Quartz Arenite Lithofacies 85 Depositional Environments 85 Depositional History and Model 89 Simonson and Guilmette Platform Evolution 92 DIAGENESIS 94 Diagenetic History of the Simonson Dolomite and Guilmette Formations 94 Introduction 94 Calcite Stabilization, Neomorphism, and Cementation 95 Silica Cementation and Replacement 98 Dolomitization and Stylolitization 105 Reservoir Characteristics of the Simonson Dolomite and Guilmette Formations 113 CONCLUSIONS 116 BIBLIOGRAPHY 118 APPENDICES 127 Appendix A. Faunal Collections 127 Appendix B. Conodont Color Alteration Data 133 Appendix C. Routine Core Analysis Test Results 134 Appendix D. Rock Classification and Porosity Data 136 Appendix E. Dolomite and Carbonate Rock Classifications 142 LIST OF FIGURES Figure Page 1. Index map of Nevada with enlargement of White Pine 2 County showing locations of three thesis map areas. 2. Time-rock model for Devonian carbonate platform across 17 central and eastern Nevada. 3. Map view showing locations of Figure 2 transect. 19 4. Isopach map of Simonson Dolomite throughout east-central 22 Nevada. 5. Isopach map of Simonson Coarse Crystalline Member. 24 6. Generalized depositional model for Simonson Coarse 29 Crystalline Member and western equivalents. 7. Suggested sequence of events responsible for shelf-wide 31 Lower-Middle Devonian unconformity. 8. Isopach map of Lower-Middle Devonian quartz sands 33 throughout eastern Nevada. 9. Photomicrograph of Lower-Middle Devonian dolomitic quartz 34 arenite. 10. Triangular QmFLt plot for Lower-Middle Devonian quartz 36 sands. 11. Isopach map of Simonson Lower Alternating Member. 38 12. Alternating nature of brown and gray beds displayed by 39 the Simonson Lower Alternating Member. 13. Upward-shallowing sequence within the Simonson Lower 40 Alternating Member. 14. Horizontal cryptalgal laminations displaying antigravity 43 structures. 15. Intraformational solution collapse breccia in the 45 Simonson Lower Alternating Member. 16. Photomicrograph of intraformational breccia showing 47 angular, laminated dolomudstone clast and surrounding carbonate matrix. 17. Generalized depositional model for Simonson Lower 49 Alternating Member and western equivalents. Figure Page 18. Isopach map of Simonson Brown Cliff Member. 51 19. Generalized depositional model for the Simonson Brown 54 Cliff Member and western equivalents. 20. Isopach map of Simonson Upper Alternating Member. 59 21. View to the northeast of the contact between the Simonson 60 Dolomite and overlying limestone cliffs of the Guilmette Formation in the Egan Range. 22. Sharp and conformable contact between Guilmette Formation 61 and underlying Simonson Dolomite UAM. 23.