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University of Florida Thesis Or Dissertation PALEOMAGNETISM AND GEOCHRONOLOGY OF THE PRECAMBRIAN MAFIC DYKE SWARMS OF INDIAN SUB-CONTINENT AND SEDIMENTARY FORMATIONS OF MONGOLIA AND KAZAKHSTAN IN CENTRAL ASIA – UNDERSTANDING THE PRECAMBRIAN PALEOGEOGRAPHY AND TECTONIC EVOLUTION OF INDIA AND CENTRAL ASIAN MICROCONTINENTS By VIMAL ROY PRADHAN A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2011 1 © 2011 Vimal Roy Pradhan 2 To my parents, wife and my son for their unconditioned love, motivation, patience, sacrifice, encouragement and support without which this dissertation would not have been possible. 3 ACKNOWLEDGMENTS I would like to express my sincere appreciation to Dr. Joseph G. Meert, the chairperson of my graduate supervisory committee, for his scientific guidance, encouragement during my graduate study, and financial support. I would also like to extend my gratitude to the members of my committee, Dr. Neil Opdyke, Dr. David Foster, Dr. Ray Russo and Dr. James Fry, for consistently guiding me through this research and offering fantastic advice and critical review. I especially want to thank Joe for encouraging creative scientific thinking and teaching me so many interesting things about Paleomagnetism, field geology and scientific writing. Words are not enough to thank my parents, Shanti Sharma and Harish Chandra Pradhan, and my wife Ritu Sharma, for all of their help along the way and being supportive during my difficult times. Special appreciation goes to my elder brother Krishan Roy Pradhan and sister-in-law Meera Sharma, my father-in-law Lalit Mohan Sharma and mother-in-law Pushpa Sharma for their love and encouragement at every step that has influenced my success. I want to thank all of my friends in geology- we have really been through everything together, those from the very beginning of my undergraduate geology in India and the ones here at UF with the highest ambitions. There are some very crucial people that contributed significantly to the science involved in this research- in lab training, analyses, field work, scientific discussion and review. They are George Kamenov, Kainian Huang, Shawn Malone, Warren Grice, Daniel Gorman, Trond Torsvik, Laura Gregory, Erfan Ali Mondal, Linda Sohl and Luke Gommermann. I especially thank Dr. Manoj Pandit and Dr. Paul Mueller for their consistent guidance and help in the successful completion of this program. I want to thank the Geological Sciences faculty for guiding me for the past five years and 4 teaching me vast amounts of geology. Finally, I thank my best friends throughout the past few years who have always lended a seemingly interested ear to my enthusiasm for science, and with whom I have had some of the greatest experiences- Alex Hastings and Jennifer Gifford. Funding for this research was provided by the National Science Foundation grants EAR04-0901; EAR05-08597 and EAR09-10888 to Dr. Joseph Meert. 5 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 9 LIST OF FIGURES ........................................................................................................ 10 LIST OF ABBREVIATIONS ........................................................................................... 14 ABSTRACT ................................................................................................................... 16 CHAPTER 1 INTRODUCTION .................................................................................................... 18 2 A CAUTIONARY NOTE ON THE AGE OF THE PALEOMAGNETIC POLE OBTAINED FROM THE HAROHALLI DYKE SWARMS, DHARWAR CRATON, SOUTHERN INDIA ................................................................................................. 21 Introductory Remarks.............................................................................................. 21 Paleomagnetism of the Harohalli Alkaline Dykes .................................................... 23 Geochronology of the Harohalli Dykes.................................................................... 25 Discussion .............................................................................................................. 27 Summary ................................................................................................................ 29 3 INDIA‘S CHANGING PLACE IN GLOBAL PROTEROZOIC RECONSTRUCTIONS: A REVIEW OF GEOCHRONOLOGIC CONSTRAINTS AND PALEOMAGNETIC POLES FROM THE DHARWAR, BUNDELKHAND AND MARWAR CRATONS .................................................................................... 39 Introductory Remarks.............................................................................................. 39 Geologic Setting ..................................................................................................... 40 The Aravalli and Bundelkhand Cratons ............................................................ 41 The Dharwar Craton ......................................................................................... 43 Methods .................................................................................................................. 45 Paleomagnetic Methods ................................................................................... 45 Geochronologic Methods.................................................................................. 46 Paleomagnetic and Geochronologic Results .......................................................... 47 Gwalior Traps ................................................................................................... 47 Paleomagnetic Results ..................................................................................... 48 Ananatapur Dykes Region ...................................................................................... 49 Geochronologic Results ................................................................................... 50 Paleomagnetic Results ..................................................................................... 51 Malani Igneous Suite Basement and Early Plutonism ............................................ 52 Discussion .............................................................................................................. 55 6 Paleoproterozoic Results (2.5Ga–1.6Ga) ......................................................... 55 Mesoproterozoic Results (1.6Ga-1.1Ga) .......................................................... 58 Neoproterozoic Results (1000-570 Ma) ............................................................ 62 Summary ................................................................................................................ 64 4 PALEOMAGNETIC AND GEOCHRONOLOGICAL STUDIES OF THE MAFIC DYKE SWARMS OF BUNDELKHAND CRATON, CENTRAL INDIA: IMPLICATIONS FOR THE TECTONIC EVOLUTION AND PALEOGEOGRAPHIC RECONSTRUCTIONS ...................................................... 85 Introductory Remarks.............................................................................................. 85 Geological Setting and Previous Work ................................................................... 87 Sampling and Methodology .................................................................................... 90 Paleomagnetic Methods ................................................................................... 90 Geochronological Methods ............................................................................... 91 Results .................................................................................................................... 93 Geochronological Results ................................................................................. 93 Paleomagnetic Results ..................................................................................... 94 Rock Magnetic Results ..................................................................................... 95 Discussion .............................................................................................................. 96 ~ 1.1 Ga Paleomagnetism ................................................................................ 96 Age implications for the Bhander-Rewa sequence of the Upper Vindhyan ................................................................................................. 97 India in Rodinia supercontinent at 1100 Ma ............................................... 99 ~ 2.0 Ga Paleomagnetism .............................................................................. 106 Tectonic evolution of the Aravalli and Dharwar protocontinents ............... 106 Implications for Columbia ......................................................................... 107 Summary .............................................................................................................. 112 5 GEOCHRONOLOGIC AND PALEOMAGNETIC CONSTRAINTS ON THE LATE NEOPROTEROZOIC – EARLY PALEOZOIC VOLCANO-SEDIMENTARY UNITS OF THE CENTRAL ASIAN OROGENIC BELT MICROCONTINENTS. .... 132 Introductory Remarks............................................................................................ 132 Geological Setting ................................................................................................. 137 Lesser Karatau Microcontinent Block ............................................................
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