Neogene Extension and Regional Rotation of the Central Mojave Desert, California
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Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1994 Neogene Extension and Regional Rotation of the Central Mojave Desert, California. Timothy Michael Ross Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Ross, Timothy Michael, "Neogene Extension and Regional Rotation of the Central Mojave Desert, California." (1994). LSU Historical Dissertations and Theses. 5701. https://digitalcommons.lsu.edu/gradschool_disstheses/5701 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. 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Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. NEOGENE EXTENSION AND REGIONAL ROTATION OF THE CENTRAL MOJAVE DESERT, CALIFORNIA A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Geology and Geophysics by Timothy Michael Ross B.S., California State University, Fresno, 1985 M.A., University of California, Santa Barbara, 1988 May 1994 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ACKNOWLEDGEMENTS I would like to thank my committee members for encouragement of my study and a thorough critique of my dissertation. In particular, my advisor, Roy K. Dokka, deserves particular thanks for guidance, monetary support and providing a relaxed atmosphere in which to study. Chad McCabe provided a paleomagnetic laboratory, where I spent many long days, and countless discussions of the fine particulars of paleomagnetism. Christopher J. Travis and David MacConnell helped with fieldwork and lively discussions on the Mojave. Giovanni Sella, Peter George and many other graduate students at LSU provided the camaraderie which makes graduate studies bearable. Jim, Pam and Scott Barber allowed me to stay at their house and sleep in a comfortable bed while doing fieldwork. My family (Lynn and Jim Ross, Deward and Lilly Dixon, Phyllis and John Ross, Kelly Olday and Richard Ross) have given me the encouragement and support through these long years in which to complete the long road to a Ph. D. Dan Lux of the University of Maine graciously allowed me to visit and investigate geochronology using his 40.Ar/39Ar laboratory. Mike Woodbume identified mammal fossils collected in my field area and provided helpful and interesting discussions of the stratigraphy and tectonic history of the Mojave Desert. I thank Louisiana State University for supporting me with a Regents Fellowship. I have also received support from Exxon, Chevron, the LSU Department of Geology and Geophysics and NSF grants to Chad McCabe (EAR 8816571 and EAR 8816826) and to Roy K. Dokka (EAR 8721022 and EAR 9004339). Giovanni Sella helped as a liason with LSU and presented this doccument on my behalf to the proper authorities. Most importantly, I owe much thanks to my wife, Dr. Joan Esther Fryxell, for support, ii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. encouragement and love. Slartibartfast (Paul Griffin Ross) helped to speed things along. iii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS ACKNOWLEDGEMENTS............................................................................................ ii LIST OF TABLES............................................................................................................ viii LIST OF FIGURES.......................................................................................................... ix LIST OF PLATES............................................................................................................. xi ABSTRACT....................................................................................................................... xii CHAPTER 1: GENERAL GEOLOGY OF THE MOJAVE DESERT AND INTRODUCTION TO THIS DISSERTATION.......................................................... 1 Introduction ............................................................................................................... 1 General Geology of the Mojave Desert ................................................................. 1 Early Miocene Regional Extension .............................................................. 3 Strike-Slip History ......................................................................................... 3 Vertical-Axis Rotations .................................................................................. 5 This Study ................................................................................................................. 6 Organization of This Dissertation ........................................................................... 7 CHAPTER 2: GEOLOGY OF THE SOUTHWEST CADY MOUNTAINS 8 Introduction ............................................................................................................... 8 General Geology ............................................................................................. 8 Descriptive Geology of the Southwest Cady Mountains ..................................... 11 Basement ......................................................................................................... 11 Formation of Poe ............................................................................................ 12 Stratigraphic Description ......................................................................... 12 Interpretation of Depositional Environment ......................................... 14 Age and Correlation ................................................................................. 16 Formation of Troy Peak ................................................................................. 17 Stratigraphic Description ......................................................................... 17 Interpretation of Depositional Environment ......................................... 18 Age and Correlation ................................................................................. 18 "Barstow Formation" ..................................................................................... 20 Stratigraphic Description ......................................................................... 20 Interpretation of Depositional Environment ......................................... 23 Age and Correlation ................................................................................. 23 Quaternary Cover ............................................................................................ 24 iv Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Interpretation of Depositional Environment .......................................... 24 Structural Relationships ........................................................................................... 26 Early Miocene Extension ............................................................................... 26 Structural Position