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Early Neoproterozoic tectonics in the Godhra-Chhota Udepur sector: Evidence for two-stage accretion in the Great Indian Proterozoic Fold Belt

Show simple item record Banerjee, A. Sequeira, N. Cogne, N. Prabhakar, N. Bhattacharya, A. 2022-04-12T05:51:08Z 2022-04-12T05:51:08Z 2022
dc.identifier.citation Lithosphere. 2022(8); 2022; ArticleID_9322892. en_US
dc.description.abstract The Great Indian Proterozoic Fold Belt (GIPFOB) is a curviplanar highly-tectonized zone of Precambrian crystalline rocks. In the GIPFOB, the N/NNE-striking western arm (the Aravalli Delhi Fold Belt, ADFB) and the E-striking southern arm consisting of the Chottanagpur Gneiss Complex (CGC) and the central/southern domains of the Satpura Mobile Belt (SMB) converge at the Godhra-Chhota Udepur sector. To investigate the tectonics of the sector, we combine the results of analyses of mesoscale and regional structures, U-Pb (zircon) geochronology, and monazite chemical dating to constrain the convergence. The sector is dominated by an ensemble of shallow-dipping granitoid mylonites (D2 deformation) and recumbently folded anatectic granulite-facies basement gneisses interleaved with allochthonous greenschist/epidote-amphibolite facies supracrustal rocks thrust top-to-the-south. The shallow-dipping carapace is traversed by a network of E-striking steep-dipping shear zones with sinistral and N-down kinematics (D3 deformation). The D3 shear zone hosted granitoids exhibit E-striking suprasolidus deformation fabrics and chessboard microstructures. In the shallow-dipping carapace, the partly overlapping stretching lineations associated with D2-D3 deformations share low-angle obliquities with the W/WNW plunging hinges of D2 recumbent folds and the upright/moderately-inclined D3 folds in the basement gneisses and the supracrustal rocks. The transition from thrust-dominated (D2) to wrench-dominated (D3) deformation involved flipping of Y and Z strain axes for similar orientations of orogen-parallel stretching caused by N-S shortening. U-Pb LA-ICP-MS (zircon) and monazite chemical dates suggest the D2-D3 deformation and felsic plutonism occurred at 0.95-0.90 Ga, the pre-D2 high-grade metamorphism in the anatectic gneisses at 1.7-1.6 Ga. The 0.95-0.90 Ga structures in the Godhra-Chhota Udepur are identical to those in CGC-SMB in the southern arm and terminate the N/NNE-striking structures in the ADFB. We suggest the GIPFOB comprises two Early Neoproterozoic accretion zones, e.g., the western arm (ADFB) and the younger (GC-SMB-CGC) southern arm. en_US
dc.publisher GeoScienceWorld en_US
dc.subject Earth Sciences en_US
dc.title Early Neoproterozoic tectonics in the Godhra-Chhota Udepur sector: Evidence for two-stage accretion in the Great Indian Proterozoic Fold Belt en_US
dc.type Journal article en_US
dc.identifier.impf y

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