Building India: Clues from the Singhbhum Craton & Southern India

该奖项旨在了解印度次大陆的地质历史及其形成的复杂性。像许多大陆一样，印度是由几个地理和地理上截然不同的元素组成的，这些元素被焊接在一起，形成了今天的印度半岛。该项目的主要调查人员正在研究印度两个研究较少的地区(印度东北部的Singhbhum Craaton和印度南部的Dharwar Craton及其周边地区)。该项目结合了古地磁和地质年代学研究，为我们提供了这些陆块在哪里以及何时并入印度的信息，以及它们在元古代(25亿至5.4亿年前)与其他陆块的关系。据推测，印度次大陆或其一些次区域可能是两个古老的超级大陆罗迪尼亚和哥伦比亚的一部分。这项研究的目的是破译这些超级大陆是如何由于板块构造而聚集和随后分散的复杂性，并检查与生物圈和气候伴随的变化的任何潜在联系。该项目将提供有关印度境内大陆区块与哥伦比亚和罗迪尼亚大陆之间缝合/裂谷地带的时间和位置的关键信息。这项工作涉及一个由来自美国、印度和加拿大的科学家组成的国际团队。除了该项目的研究目标外，该奖项还支持STEM学科的本科生和研究生的培训。主要调查人员正在努力通过招收地球科学专业中任职人数不足的群体的学生，来扩大代表不足群体在科学、技术和经济研究方面的参与。该项目的研究成果将通过顶级期刊、会议、在K-12教育机构的演讲和其他公共宣传努力来传播。我们对罗迪尼亚和哥伦比亚等元古代超大陆的了解是基于一个相对较小(但不断增长)的古地磁数据库。东冈瓦那(澳大利亚、南极洲、印度、马达加斯加和斯里兰卡)是超级大陆模式的关键部分。只有印度和澳大利亚含有相对未变形和未变质的岩石，被认为是对古地磁研究有用的。我们在这项提议中的目标是通过结合使用古地磁学和地质年代学来填补印度漂移史上的关键空白。这些结果为研究人员提供了重建过去大陆组装的关键纽带。反过来，这些重建将被评估它们对全球气候变化、演化、地幔动力学和矿产勘探的影响。这项建议的主要重点是从印度南部Singhbhum克拉通和当地的一系列岩墙中获得高质量的古地磁数据。这些数据将包括地质年代学数据和现场测试，以完全限制岩石中的磁化年龄。这项建议中使用的方法已经被证明在提高我们对印度-S与其他陆地关系的了解方面是有效的。这一提议将从Singhbhum克拉通(印度中东部)和最南端的达瓦尔克拉通(印度南部)获得年代准确的古地磁极，以努力：(A)扩大印度元古界古地磁和地球年代学数据库(其条形码)；(B)利用古地磁测试整个印度中部构造带南北克拉通之间的克拉通相干性；(C)确定已在巴斯塔尔和达瓦尔克拉通建立的~1.9Ga辐射岩墙群的范围；以及(D)确立印度在罗迪尼亚和哥伦比亚超大陆的地位。这些想法将通过收集印度境内目标地区的古地磁和地质年代学样本来检验。

This award is focused on understanding the geological history of the Indian subcontinent and the complexities of its formation. Like many continents, India is composed of several geographically and geologically distinct elements that were welded together to form modern-day Peninsular India. The principal investigators for this project are examining two regions in India that are poorly studied (Singhbhum craton-northeast India and the southern Indian Dharwar craton and surrounding region). The project involves a combination of paleomagnetic and geochronologic studies that provide us with information regarding where and when these continental blocks were incorporated into India along with their relationship to other landmasses during the Proterozoic Eon (2.5 billion to 540 million years ago). It is hypothesized that the Indian subcontinent or some of its sub-regions may have been part of two ancient supercontinents called Rodinia and Columbia. This research is aimed at deciphering the complexities of how these supercontinents were assembled and subsequently dispersed due to plate tectonics, as well as examining any potential links to concomitant changes in the biosphere and climate. This project will provide key information regarding the timing and location of the suture/rift zones between continental blocks within India and the larger landmasses of Columbia and Rodinia. The work involves an international team of scientists from the United States, India, and Canada. In addition to the research objectives of the project, the award is supporting the training of undergraduate and graduate graduate students in a STEM discipline. The principal investigators are working to broaden participation of underrepresented groups in STEM by recruiting students from under-represented groups in the Geosciences. The research results from this project will be disseminated through top journals, meetings, presentations at K-12 educational institutions and other public outreach efforts. Our knowledge of Proterozoic supercontinents such as Rodinia and Columbia are based on a relatively small (but growing) paleomagnetic database. East Gondwana (Australia, Antarctica, India, Madagascar and Sri Lanka) is a critical piece of the supercontinental models. Only India and Australia contain rocks that are relatively un-deformed and un-metamorphosed considered useful for paleomagnetic studies. Our goal in this proposal is to fill in critical gaps in India's drift history through the combined use of paleomagnetism and geochronology. The results are providing researchers with key tie points in reconstructing past continental assemblies. These reconstructions, in turn, will be evaluated for their effects on global climate change, evolution, mantle dynamics and mineral exploration. The key focus of this proposal is to obtain high-quality paleomagnetic data from a series of dykes in the Singhbhum craton and localities in southern India. These data will include geochronological data and field tests to fully constrain the age of magnetization in the rocks. The methodologies employed in this proposal have already proven effective in improving our knowledge of India?s relationship to other landmasses. This proposal will obtain well-dated paleomagnetic poles from the Singhbhum craton (east-central India) and the southernmost Dharwar craton (south India) in an effort to: (a) expand the Proterozoic paleomagnetic and geochronological database for India (its barcode); (b) use paleomagnetism to test cratonic coherence between the north and south Indian cratons across the Central Indian Tectonic zone during the Proterozoic; (c) establish the extent of a proposed ~1.9 Ga radiating dyke swarm already established in the Bastar and Dharwar cratons and (d) establish the position of India in the supercontinents of Rodinia and Columbia. These ideas will be tested by collecting paleomagnetic and geochronologic samples from the targeted regions within India.