Building India: Clues from the Singhbhum Craton & Southern India

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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.