Further Refinement of India's Proterozoic Paleogeography and Geochronology

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。对盘古大陆形成之前的地球古地理知之甚少。该研究项目的目标是更好地了解元古宙古地理，特别是冈瓦纳、罗迪尼亚和哥伦比亚等更古老的超大陆。东冈瓦纳（澳大利亚、南极洲、印度、马达加斯加和斯里兰卡）被认为是冈瓦纳、罗丁尼亚和哥伦比亚超大陆的重要组成部分。关于东冈瓦纳合并的确切时间，本研究拟检验的主要假设有：(a)东冈瓦纳的克拉通内核是太古宙时期形成的原始大陆；(b)东冈瓦纳在中元古代聚集；(c)东冈瓦纳组合与新元古代的大冈瓦纳组合同时发生。这个项目的重点是印度，那里暴露着相对未变形和未变质的元古代岩石，这使得填补印度的一些关键空白成为可能。通过古地磁和U-Pb年代学的结合来研究中国的漂移历史。具体目标包括印度的两个Purana盆地，以及侵入Dharwar、Singhbhum和Bundelkhand克拉通的岩脉。古地磁资料结合可靠的年龄信息，可以为造山带、岩脉等地质特征的定位提供依据，用于提出超大陆合并假说。这项关于印度次大陆的研究结果将用于改进和发展全球古地理模型。结果将对过去的气候变化（包括地球历史上最严重的冰川作用）、全球大陆构造与寒武纪生命演化之间的关系以及导致超级大陆形成和分裂的地幔动力学提供重要的约束。这项研究将为雪球地球气候模型、埃迪卡拉纪寒武纪辐射以及通常在大陆碰撞和分裂期间形成的不可再生矿床的位置提供一级约束。本项目由地球科学部大地构造学项目联合支持，国际科学与工程办公室（非洲、近东和南亚项目）资助。

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).