Paper Number: 2851
Proterozoic tectono-magmatic
processes in Aravalli- Delhi Mobile belt, NW India and its implication
to Columbia and Rodinia Supercontinents
Tiwari, S.K.1, Biswal, T.K.1
1Department of Earth sciences, Indian Institute of Technology Bombay, sudheer030192@gmail.com
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The northwestern part of Indian peninsula consists of Precambrian terrane that bears the imprints of Supercontinents assembly like Columbia and Rodinia. The age of Columbia Supercontinent is Paleoproterozoic to Mesoproterozoic whereas Rodinia Supercontinent belongs to Neoproterozoic age. The Aravalli- Delhi Mobile belt is a key component in paleogeographic reconstruction of both Proterozoic Columbia and Rodinia accretion, break up and their dispersal. Columbia has assumed to be amalgamated during 2.1 Ga to 1.85 Ga time period and Rodinia amalgamated during 1.1 Ga to 750Ma.
Geochronologic, paleomagnetic, tecono- magmatic and petrologic data suggest that the Aravalli- Delhi mobile belt experienced its close packing during ~1.90- 1.85 Ga as observed by the Aravalli orogeny in a continental arc setting. Globally this event is related to the amalgamation of different block of Aravalli- Delhi Mobile belt which creates a part of the Columbia Supercontinent. The attempted breakup of Columbia Supercontinent starts in ~1.80- 1.70 Ga through extensional tectonic regime which is related to intrusion of granitic bodies (e.g. Khetri ~ 1.80 Ga) in northern part of Aravalli- Delhi mobile belt and also synchronous with granulite metamorphism represented by Sandmata granulite (~1.72 Ga) in Sandmata Complex. This indicates juvenile addition to the crust through emplacement of magmas, and resultant crustal growth during the late Paleoproterozoic. The changes in Paleolatitudes of Indian landmass during ~ 1.70- 1.30 Ga is correlated with global plate movements and final breakup of Columbia.
After breakup of Columbia Supercontinent the dispersed Indian landmasses consisted of three smaller microcontinental blocks namely North Indian block, South Indian block and Marwar block amalgamated during Grenvillian orogeny (~1.5- 1.0 Ga). The amalgamated North Indian block and Marwar block of Aravalli- Delhi Mobile belt is part of Rodinia Supercontinent. Various tectono- magmatic and metamorphic events took place in South Delhi Terrane of Aravalli- Delhi Mobile belt during ~885- 632 Ma which is related to the final phase of assembly and breakup of Rodinia Supercontinent. The emplacement of G1 (885.3±6 Ma to 826.6±8 Ma), G2 (793±21 Ma to 780.1±9 Ma), G3 (758±45 Ma to 750±21 Ma) granites of Ambaji area and Malani magmatic event (~ 750- 650 Ma) of Neoproterozoic age of South Delhi Terrene bear testimony for such tectonic frame within a global scenario of Rodinia Supercontinent.
Thus the Aravalli- Delhi Mobile belt preserves an integral cycle of Columbia and Rodinia Supercontinent amalgamation, break up and its dispersal.