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The Role of Transverse Faults in Great Basin Extension: Transfer Faults Or N-S Extension?

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The Role of Transverse Faults in Great Basin Extension: Transfer Faults Or N-S Extension? UNLV Retrospective Theses & Dissertations 1-1-2005 The role of transverse faults in Great Basin extension: Transfer faults or N-S extension? Tandis S Bidgoli University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/rtds Repository Citation Bidgoli, Tandis S, "The role of transverse faults in Great Basin extension: Transfer faults or N-S extension?" (2005). UNLV Retrospective Theses & Dissertations. 1820. http://dx.doi.org/10.25669/5ag1-zwwy This Thesis is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in UNLV Retrospective Theses & Dissertations by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawrings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. ProQuest Information and Learning 300 North Zeeb Road. Ann Arbor, Ml 48106-1346 USA 800-521-0000 UMI’ Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. THE ROLE OF TRANSVERSE FAULTS IN GREAT BASIN EXTENSION: TRANSFER FAULTS OR N-S EXTENSION? by Tandis S. Bidgoli Bachelor of Science San Francisco State University 2002 A thesis submitted in partial fulfillment of the requirements for Master of Science Degree in Geoscience Department of Geoscience College of Sciences Graduate College University of Nevada, Las Vegas August 2005 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: 1429694 UMI Microform 1429694 Copyright 2006 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48105-1346 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Thesis Approval IJNTV The Graduate College University of Nevada, Las Vegas Jung—24- ,20_o§ The Thesis prepared by Tandis S. Bidgoli Entitled The Role of Transverse Faults in Great Basin Kytrensinn; TrangfpT Faults or N-S Extension? is approved in partial fulfillment of the requirements for the degree of Master of Science in Geoscience Examination Committee Chair Dean of the Graduate College . I Examination Committee Member Examination Committee Member Graduate College Facidty Representative 11 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ABSTRACT The Role of Transverse Faults in Great Basin Extension: Transfer Faults or N-S Extension? by Tandis S. Bidgoli Dr. Wanda J. Taylor, Examination Committee Chair Professor of Geology University of Nevada, Las Vegas New geologic map data (1:24,000 scale), geometric analyses, and kinematic analyses in the vicinity of the Crescent Spring fault zone (CSFZ), an E-W-striking fault zone in eastern Nevada, allow the recognition of four distinct extensional episodes. The episodes are pre-volcanic (pre-27 Ma), syn-volcanic (-27-18 Ma), Miocene (?) post-volcanic, and Miocene (?) - Pliocene or Quaternary post-volcanic extension. This extensional pattern, which is consistent with other fault studies along the broadly defined Timpahute lineament, has several important aspects. (I) Transverse faults of the CSFZ are normal faults that accommodated a distinct N-S extensional event. (2) The strain field within this part of the Great Basin reoriented at least twice during the Tertiary, from E-W extension to N-S extension and back to E-W extension. (3) The dominantly south- dipping, transverse normal faults moved crustal material southward, which may explain N-S shortening during large-magnitude E-W extension at the latitude of Las Vegas. (4) The eastern part of the Timpahute lineament is a regional transfer fault system that accommodated changes in the magnitude, timing, location, and direction of extension. Ill Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS ABSTRACT.................................................................................................................. ni LIST OF FIGURES....................................................................................................... vi ACKNOWLEDGEMENTS.......................................................................................... vii CHAPTER 1 INTRODUCTION................................................................................... 1 CHAPTER 2 REGIONAL GEOLOGY......................................................................... 6 Structural and Tectonic Background ......................................................................... 6 East-West-Trending Lineaments ............................................................................. 10 CHAPTERS STRATIGRAPHY................................................................................. 13 Paleozoic Stratigraphy ............................................................................................. 13 Sub-Tertiary Unconformity ..................................................................................... 14 Tertiary Stratigraphy ................................................................................................14 CHAPTER 4 METHODS............................................................................................16 CHAPTER 5 FAULT DESCRIPTIONS......................................................................18 -East-West-Striking Faults ...................................................................................... 18 -North-South-Striking Faults ..................................................................................21 CHAPTER 6 FOLD DESCRIPTIONS........................................................................ 24 CHAPTER 7 STRUCTURAL AND TECTONIC INTERPRETATIONS ................... 25 Mesozoic Contraction ..............................................................................................25 Prevolcanic Extension ..............................................................................................26 Synvolcanic Extension .............................................................................................30 Postvolcanic Miocene (?) Extension ........................................................................ 32 Postvolcanic Miocene (?) to Pliocene or Quaternary Extension ...............................35 CHAPTERS DISCUSSION........................................................................................37 Regional Transverse Zone .......................................................................................37 Implications of N-S Extension .................................................................................42 CHAPTER 9 SUMMARY AND CONCLUSIONS.....................................................51 IV Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIX I METHODS................................................................................................... 83 APPENDIX II ANALYTICAL DATA.............................................................................. 89 REFERENCES....................................................................................................................... 98 VITA...................................................................................................................................... 110 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LIST OF FIGURES Figure 1 Tectonic Setting of Nevada..................................................................................54 Figure 2 Transverse Structure Models ............................................................................... 56 Figure 3 Location Map with Major Structural Elements .................................................. 57 Figure 4 Major Elements of a Collapsed Caldera ..............................................................59 Figure 5 Tectonomagmatic
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