In paleogeographic reconstructions of the Columbia and Rodinia Supercontinents,the position of the Greater India landmass is ambiguous.This,coupled with a limited understanding of the tectonic evolution of the mobile belts along which the mosaic of crustal domains in India accreted,impedes precise correlation among the dis-persed crustal fragments in supercontinent reconstructions.Using structural,metamorphic phase equilibria,chronological and geochemical investigations,this study aims to reconstruct the tectonic evolution of the Chottanagpur Gneiss Complex(CGC)as a distinct crustal block at the eastern end of the Greater Indian Protero-zoic Fold Belt(GIPFOB)along which the North India Block(NIB)and the South India Block(SIB)accreted.The study focuses on two issues,e.g.dating the Early Neoproterozoic(0.92 Ga)accretion of the CGC with the NIB con-temporaneous with the assembly of Rodinia,and documenting the widespread(＞24,000 km2)plutonism of 1.5-1.4 Ga weakly peraluminous,calc-alkalic to alkali-calcic and ferroan A-type granitoids(±garnet)devoid of mafic microgrannular enclaves and coeval mafic emplacements in the crustal block.These dominantly within-plate granitoids arguably formed by asthenospheric upwelling induced partial melting of garnet-bearing anatectic quartzofeldspathic gneisses that dominate the Early Mesoproterozoic basement of the block.The major and trace element chemistry of the granitoids is similar to the 1.35-1.45 Ga A-type granitoids in Laurentia/Amazonia emplaced contemporaneous with the 1.5-1.3 Ga breakup of the Columbia Supercontinent.This study suggests the Chottanagpur Gneiss Complex occured as a fragmented crustal block following the breakup of the Columbia Supercontinent;the crustal block was subsequently integrated within India during the Early Neoproterozoic oblique accretion between the NIB and SIB contemporaneous with the Rodinia Super-continent assembly.

Nicole Sequeira;Abhijit Bhattacharya;Elizabeth Bell

Department of Geology and Geophysics,Indian Institute of Technology,Kharagpur 721 302,India;School of Earth,Ocean and Atmospheric Sciences,Goa University,Taleigao,Goa 403516,India;Department of Earth,Planetary and Space Sciences,University of California,595 Charles Young Drive East,Los Angeles,CA 90095-1567,USA

地学前缘（英文版）

[1]Nicole Sequeira;Abhijit Bhattacharya;Elizabeth Bell-.The～1.4 Ga A-type granitoids in the"Chottanagpur crustal block"(India),and its relocation from Columbia to Rodinia?)[J].地学前缘（英文版）,2022(02):405-429

Chottanagpur,Supercontinents,Gneiss,Protero,GIPFOB,NIB,temporaneous,plutonism,alkalic,ferroan,microgrannular,emplacements,anatectic,quartzofeldspathic,Laurentia,Amazonia,occured

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