KINEMATIC AND TEMPORAL EVOLUTION OF THE SOUTHERN APPALACHIAN FORELAND FOLD­THRUST BELT: CONSTRAINTS FROM STRUCTURAL, MAGNETIC AND RADIOMETRIC ANALYSES by James Stephen Hnat A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Geology) in The University of Michigan 2009 Doctoral Committee: Professor Ben A. van der Pluijm, Co­Chair Professor Rob Van der Voo, Co­Chair Professor Roman Hryciw Associate Professor Todd Ehlers Assistant Professor Nathan Niemi © James Stephen Hnat 2009 To Amanda, with love and thanks ii ACKNOWLEDGEMENTS Many people provided me with support and friendship during my time here as a graduate student. Firstly, I must thank Ben van der Pluijm for allowing me the opportunity to work with him, for his constant encouragement and for the insightful discussions we have had pertaining to geology, great television shows and life in general. I am deeply grateful to Rob Van der Voo, whose patience, support and education over the years has helped me develop into a scientist and for serving as a role model. I genuinely appreciate the significant effort of patiently reviewing this dissertation by my other committee members Roman Hryciw, Todd Ehlers and Nathan Niemi. This dissertation would not have been remotely possible without the many geologists I worked with who have local geologic knowledge and who graciously helped me during my fieldwork. Pete Lemiszki, from the Tennessee Geological Survey, generously provided me with assistance for all phases of my research in Tennessee. The help of Ed Osborne (Alabama Geological Survey), Jon Goodwin and Bob Mumm (Illinois Geological Survey) and Ray Daniel and Ryan Pinkston (Kentucky Geological Survey) is also appreciated. I am thankful for the many discussions with the modern titans of Appalachian geology, Bill Thomas and Bob Hatcher, both of whom provided help with many aspects of this dissertation. iii Josep Parés is thanked for assistance in the paleomagnetic lab, along with the great conversations and friendship. Ar‐Ar dating would not have been possible without Chris Hall. I am thankful to the many graduate students and postdocs from the PaSTeL group over the years. Eric Tohver, John Solum, Jeff Rahl, Phil McCausland, Belén Oliva‐Urcia, Philip Ong, Maodu Yan, Sam Haines, Sara Tourscher, Sasha Abrajevitch, Daming Wang, Matt Domeier, Anja Schleicher and Charlie Verdel all deserve mentioning as each provided me with both guidance and friendship. I also appreciate the friendship of my fellow graduate students, Franek Hasiuk, Matt Manon, Sarah Rilling, Matt Densmore and Darius Dixon, who all gave me a reason to look forward to Thursdays. I owe thanks to two of my previous educators, my 8th grade earth science teacher, Emory Keith, and my undergraduate advisor, Paul Ryberg, both of whom inspired me to pursue a career in the earth sciences. My family’s love and support over the years was essential to my development as a scientist. My grandfather, perhaps unwittingly, planted the seeds for my love of science and discovery at an early age. I will always appreciate the effort my parents made during my high school years to drive their nerdy kid to and from various science team practices. Finally, I am eternally grateful to my wife, whose love, support and encouragement has provided me with the strength to trudge through this whole process. iv TABLE OF CONTENTS DEDICATION ............................................................................................................................................... ii ACKNOWLEDGEMENTS ....................................................................................................................... iii LIST OF FIGURES ..................................................................................................................................... ix LIST OF TABLES ..................................................................................................................................... xiv LIST OF APPENDICES ........................................................................................................................... xv ABSTRACT ................................................................................................................................................ xvi CHAPTER I INTRODUCTION ............................................................................................................. 1 OROGENIC CURVATURE .................................................................................................................... 1 AGE OF DEFORMATION ..................................................................................................................... 7 OUTLINE OF DISSERTATION ........................................................................................................... 9 REFERENCES ....................................................................................................................................... 13 CHAPTER II DIFFERNTIAL DISPLACEMENT AND ROTATION IN THRUST FRONTS: A MAGNETIC, CALCITE TWINNING AND PALINSPASTIC STUDY OF THE JONES VALLEY THRUST, ALABAMA, US APPALACHIANS ..................................... 18 ABSTRACT ............................................................................................................................................. 18 INTRODUCTION .................................................................................................................................. 19 STRUCTURAL SETTING ................................................................................................................... 21 Appalachian foreland thrust belt ........................................................................................... 21 Jones Valley thrust fault ............................................................................................................. 24 Displacement along the Jones Valley thrust fault ........................................................... 25 UNIT DESCRIPTION .......................................................................................................................... 31 PALEOMAGNETISM AND MAGNETIC SUSCEPTIBILITY ................................................... 32 Methods ............................................................................................................................................. 32 Paleomagnetic results ................................................................................................................. 34 Relative timing of magnetization ........................................................................................... 39 AMS Results ..................................................................................................................................... 41 CALCITE TWINNING ......................................................................................................................... 47 Methods ............................................................................................................................................. 47 Results ................................................................................................................................................ 49 DISCUSSION .......................................................................................................................................... 49 CONCLUSION ....................................................................................................................................... 55 v ACKNOWLEDGEMENTS .................................................................................................................. 57 REFERENCES ....................................................................................................................................... 58 CHAPTER III REMAGNETIZATION IN THE TENNESSEE SALIENT, SOUTHERN APPALACHIANS, USA: CONSTRAINTS ON THE TIMING OF DEFORMATION ....... 65 ABSTRACT ............................................................................................................................................. 65 INTRODUCTION .................................................................................................................................. 66 TENNESSEE SALIENT ...................................................................................................................... 71 Regional Structure ........................................................................................................................ 71 Previous Paleomagnetic Work ................................................................................................ 74 PALEOMAGNETIC ANALYSIS OF THE TENNESSEE SALIENT ........................................ 76 Methods ............................................................................................................................................. 76 Chickamauga Limestone Results ............................................................................................ 77 Rome Formation Redbed Results .......................................................................................... 84 Red Mountain Formation Redbed Results ......................................................................... 90 DISCUSSION .......................................................................................................................................... 96 Age and Relative Timing of Magnetization in the Tennessee Salient ....................