Further Refinement of India's Proterozoic Paleogeography and Geochronology

该奖项由2009年《美国复苏和再投资法案》(公法111-5)资助。盘古超大陆形成前的地球古地理鲜为人知。这项研究项目的目标是更好地了解元古界古地理，特别是更古老的超大陆冈瓦那、罗迪尼亚和哥伦比亚。东冈瓦那(澳大利亚、南极洲、印度、马达加斯加和斯里兰卡)被认为是冈德瓦南、罗迪尼安和哥伦比亚超级大陆的关键部分。关于东冈瓦那混杂作用确切时间的主要假设是：(A)东冈瓦那克拉通核是太古代形成的原始大陆；(B)东冈瓦那是在中元古代组装的；(C)东冈瓦那组装是在新元古代与大冈瓦那组装一起发生的。该项目聚焦于印度，那里出露了相对未变形和未变质的元古界岩石，从而有可能通过结合使用古地磁学和U-Pb年代学来填补印度S漂移史的一些关键空白。具体目标包括印度的两个普罗纳盆地，以及侵入达瓦尔、辛格汉德和邦德尔坎德克拉通的岩脉。古地磁数据与可靠的年龄信息相结合，可以为用于发展超大陆融合假说的造山带和岩脉等地质特征的定位提供证据。这项关于印度次大陆的研究成果将用于改进和发展全球古地理模型。这一结果将对过去的气候变化(包括地球历史上最严重的冰川)、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解体的地幔动力学提供重要的制约。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解体期间形成的不可再生矿藏的位置提供一阶约束。该项目由地球科学部的构造计划共同支持，并由国际科学与工程办公室(非洲、近东和南亚计划)赞助。

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).