Further Refinement of India's Proterozoic Paleogeography and Geochronology

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The paleogeography of the Earth before the formation of the Pangea supercontinent is poorly known. The goal of this research project is to better understand Proterozoic paleogeography and, in particular, the older supercontinents of Gondwana, Rodinia and Columbia. East Gondwana (Australia, Antarctica, India, Madagascar and Sri Lanka) is considered a critical piece of the Gondwanan, Rodinian and Columbian supercontinents. The main hypotheses regarding the exact timing of East Gondwana amalgamation to be tested in this study are: (a) the cratonic core of East Gondwana was the original continent formed during the Archean time; (b) East Gondwana was assembled during the Mesoproterozoic; and (c) East Gondwana assembly took place in conjunction with the assembly of greater Gondwana during the Neoproterozoic. This project focuses on India where relatively undeformed and unmetamorphosed Proterozoic rocks are exposed making it possible to fill some critical gaps in India?s drift history through the combined use of paleomagnetism and U-Pb geochronology. Specific targets include two of the Purana basins in India along with dikes intruding the Dharwar, Singhbhum and Bundelkhand cratons.Paleomagnetic data in combination with reliable age information can provide evidence for the orientation of geologic features such as orogenic belts and dikes used in developing supercontinent amalgamation hypotheses. Results from this research on the Indian subcontinent will be used to improve and develop global paleogeographic models. Result will provide important constraints on past climate change (including the most severe glaciations in earth history), the relationship between global continental configurations and the evolution of life in the Cambrian, and mantle dynamics leading to the formation and breakup of supercontinents. This research will provide first order constraints for snowball earth climate models, the Ediacaran Cambrian radiation and the loci of non-renewable mineral deposits that typically form during continental collision and breakup.This project is co-supported by the Tectonics program of the Division of Earth Sciences, and sponsored also by the Office of International Science and Engineering (Africa, Near East, and South Asia Program).