PALEOGEOGRAPHIC RECONSTRUCTION OF PART OF EASTERN GONDWANALAND: PETROFACIES AND DETRITAL GEOCHRONOLOGIC STUDY OF PERMO-CARBONIFEROUS GONDWANAN SEQUENCES OF INDIA AND BANGLADESH by Nur Uddin Md. Khaled Chowdhury A thesis submitted to the Graduate faculty of Auburn University in partial fulfillment of the requirements for the Degree of Master of Science in Geology Auburn, Alabama December 13, 2014 Keywords: Gondwana, Permo-Carboniferous, Petrofacies, 40Ar/39Ar Geochronology, India and Bangladesh Approved by: Ashraf Uddin (Chair), Professor of Geology and Geography Charles E. Savrda, Professor of Geology and Geography David T. King, Jr., Professor of Geology and Geography Willis E. Hames, Professor of Geology and Geography Abstract PALEOGEOGRAPHIC RECONSTRUCTION OF PART OF EASTERN GONDWANALAND: PETROFACIES AND DETRITAL GEOCHRONOLOGIC STUDY OF PERMO-CARBONIFEROUS GONDWANAN SEQUENCES OF INDIA AND BANGLADESH This study has been carried out focusing on petrofacies and geochronology of Permo-Carboniferous Gondwanan sequences of Barapukuria, Dighipara, and Khalaspir coal basins in the Bengal Basin and Jharia Basin in the Eastern India in order to better reconstruct regional detrital and tectonic histories of Late Paleozoic Gondwanan basins of South Asia. Sandstone petrographic studies of Permo-Carboniferous Gondwanan sequences reveal differences in sandstone modes between sediments from India and the Bengal Basin. Modal compositions vary among various basins and among sandstones from different stratigraphic levels of the same basin. These compositional differences may be attributed to differences in source rocks. Heavy mineral assemblages in Gondwanan sequences of Bangladesh and India are dominated by a few mineral groups, including garnet, apatite, zircon, rutile, tourmaline, sphene, epidote, siderite and opaques. Microprobe studies of garnets show all analyzed grains are almandine rich and indicate sources from amphibolite facies, granulite facies, and pegmatites. Ca-Fe(tot)-Mg plots suggest that tourmaline grains ii were derived from Ca-poor metapelites, metapsammites, and quartz tourmaline rocks, with one exception. The exceptional sample from Dighipara appears to have derived from Ca-rich metapelites, metapsammites, and calc-silicate rocks. Laser 40Ar/39Ar analyses of detrital muscovites show mostly polymodal distributions of cooling ages indicating multiple source terranes. Age distributions for Indian sediments significantly differ from those of the Bengal Basin samples. Age distributions from Bengal samples strongly fall in a narrow zone of Cambro-Ordovician (470 – 520 Ma). In contrast, Indian samples are more scattered (480 – 1830 Ma) and include more Neoproterozoic cooling ages. However, Indan samples also include significant age distributions of Cambro-Ordovician. Within the Indian basin, the age distributions of the older Talchir Formation significantly differ from those of the younger Barakar sandstones. Stratigraphic changes in the modes of age distributions for muscovites may reflect changes in source terranes through time. Similarities between the ages of the present study to published geochronology of the Kuunga orogen, Shingbhum craton, Meghalayan craton, and/or Eastern Ghats Mobile Belt are interpreted to indicate these regions are the most probable sources of Gondwanan sediments in Bengal Basin and the Jharia Basin of eastern India. iii Acknowledgments It is my pleasure to thank all those who assisted directly and indirectly with my thesis. I am pleased to thank the almighty God who has been with me all the way and given me the scope to study about the mystery of the Earth. It was a really enjoyable experience to work with Dr. Ashraf Uddin, my thesis advisor. I appreciate all his help and support that he provided to me for last two years. Dr. Uddin helped me not only as the principal advisor but also as a real guardian to get the best outcome of this research. I would also like to express my heartfelt thanks to Dr. Charles E. Savrda, David T. King, Jr., and Willis E. Hames for their contributions to this research as my thesis committee members. Dr. Savrda helped with significant editing in this thesis. Dr. Hames helped me understand many aspects of detrital geochronology. I am grateful to Dr. King, for giving me a better handle on stratigraphy. Also, I would like to thank all other faculty members of Geology and Geography at Auburn University. Auburn University, American Association of Petroleum Geologists, and the Geological Society of America provided financial assistance without which this research would not have been possible. I would like to express my heartfelt gratitude to Dr. Abhijit Basu from Indiana University and Dr. Sukanta Dey, Indian School of Mines for their help in collecting samples from the Jharia Basin, India. Mrs. Munira Akhter, former director general of Geological Survey of Bangladesh (GSB) and Mr. Akhtarul Ahsan iv (Rohan) helped me tremendously to collect sediment core samples from Bengal Basin. I very much appreciate their help. I want to thank Mr. Chris Fleisher of University of Georgia for his help with microprobe analysis. I am also grateful to Ms. Sheila Arington and Delaine Tease for their support with administrative work. I thank Dr. Zeki Billor for his guidance in muscovite separation. I also want to thank Ruhollah Keshvardoost and Ziaul Haque for their enormous support and help during this work. I would also like to thank all graduate students and my colleagues, for their help and support. Finally, I would like to thank my parents, without whom nothing would have been possible for me, and my siblings for all their continuous support and encouragement. v Table of Contents Abstract…………………………………………………………………………………………………….………..………….ii Acknowledgements……………………………………………………………………………………….………………iv List of Tables…………………………………………………………………………………………………….……………xi List of Figures…………………………………………………………………………………………………………….…xiii List of Abbreviation………………………………………………………………………………….……..…….……..xx Chapter 1: Introduction………………………………………………………………………………………….………1 1.1 Introduction………………………………………………………………………………………..……1 1.2 Location of the Study Area……………………………………………..……………………..…3 1.3 Previous Works………………………………………………………………………………………...5 1.4 Objectives…………………………………………………………………….…………………………..8 Chapter 2: General Geology of the Study Area..…………………… …………………………………....10 2.1 Introduction……………………………………………………………………………………..…….10 2.2 Distribution and Tectonic Evolution of Gondwanan Sequences of Peninsular India………………………………………………………………….………………………..11 2.3 Jharia Basin……………………………………………………………………………….……………17 2.3.1 Structural framework of Jharia Basin………………………………..……….17 2.3.2 Stratigraphy of the Jharia Coal Basin……………………………….…………21 vi 2.4 Gondwanan Sequences of Bangladesh…………………………………………………...23 Chapter 3: Sandstone Petrography……………...………………………………………………………….…..27 3.1 Introduction………………………………………………………………………………….………..27 3.2 Methods…………………………………………………………………………………………………28 3.3 Petrography………………………………………………………………………………….………..31 3.3.1 Petrography of Talchir Formation Jharia Basin, India…………..…….31 3.3.2 Petrography of Barakar Formation Jharia Basin, India……………….34 3.3.3 Petrography of Barapukuria Coal Basin, Bangladesh..………….…….37 3.3.4 Petrography of Dighipara Coal Basin, Bangladesh………………….….39 3.3.5 Petrography of Khalaspir Coal Basin, Bangladesh……………………...42 3.4 Sandstone Modes………………………………………………………………………………....45 3.5 Petrofacies Evalution ……………………………………………………………………………..47 Chapter 4: Heavy Mineral Analyses…………….………………………………………………………………..52 4.1 Introduction……………………………………………………….………………………………….52 4.2 Methods…………………………………………………………………………………………………54 4.3 Results…………………………………………………………………………………………………...57 4.4 Provenance…………………………………………………………………………………………....69 Chapter 5: Microprobe Analyses………………………………………………………………………………..…73 5.1 Introduction…………………………………………………………………………………………...73 vii 5.2 Mineral Chemistry………………………………………………………………………………....74 5.3 Sample Preparation………………………………………………………………………………..75 5.4 Electron Microprobe……………………….……………………………………………………..76 5.5 Results…………………………………………………………………………………………………...79 5.5.1 Garnet……………………………………………………………………………………….79 5.5.2 Tourmaline……………………………………………………………………………..…84 5.5.3 Chrome spinel……………………………………………………………………………86 5.6 Provenance…………………………………………………………………………………………….87 5.6.1 Garnet……………………………………………………………………………………….87 5.6.2 Tourmaline……………………………………………………………………………..…88 5.6.3 Chrome spinel……………………………………………………………………………88 Chapter 6: Whole Rock Geochemistry…..…………...….…………………………………………………....89 6.1 Introduction…………………………………………………………………………………………...89 6.2 Methods…………………………………………………………………………………………………90 6.3 Results……………………………………………………………………………………………………91 6.3.1 Major elements…………………………………………………………………………91 6.3.2 Trace elements and rare earth elements……………………………………96 6.4 Weathering and Diagenesis in the Source Terranes………………………………..97 6.5 Provenance and Tectonic Settings………………………………………………………..100 viii Chapter 7: Detrital 40Ar/39Ar Geochronology..…………...….…………………………………………..104 7.1 Introduction………………………………………………………………………………………….104 7.2 40Ar/39Ar Geochronology of Detrital Muscovite …………………………………105 7.3 Analytical Techniques ……………………………………………………………………….…106 7.3.1 Analytical principles…………………………………………………………………106 7.3.2 Sample irradiation……………………………………………………………………106 7.3.3 Age determination…………………………………………………………………..108 7.4 Methodology………………………………………………………………………………………..108 7.5 40Ar/39Ar Results…………………………………………………………………………………..110 7.6 Provenance Interpretation……………………………………………………………………119 Chapter 8: Summary and Discussion……………….…………………………………………………………122