The Bastar craton,central India: A window to Archean – Paleoproterozoic crustal evolution |
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| Institution: | 1. National Taiwan Normal University, Department of Earth Science, 88 Tingzhou Road Section 4, Taipei 11677, Taiwan;2. School of Studies in Geology and Water Resource Management, Pt. Ravishankar Shukla University, Raipur 492010, Chhattisgarh, India;3. University of Western Australia, School of Earth Sciences, 35 Stirling Highway, 6009, Australia;4. National Institute of Technology, Department of Applied Geology, Raipur, Chhattisgarh 492010, India;5. Govt. V.Y.T.P.G. Autonomous College, Department of Geology, Durg, Chhattisgargh 491001, India;1. Centre for Earth, Ocean & Atmospheric Sciences (CEOAS), University of Hyderabad, Hyderabad 500 046, India;2. School of Earth Sciences and Resources, China University of Geosciences Beijing, 29 Xueyuan Road, Beijing 100083, China;3. Centre for Tectonics, Resources and Exploration, Department of Earth Sciences, University of Adelaide, SA 5005, Australia;4. Department of Geology, Northwest University, Xi''an 710069, China;5. Department of Geology, University of Delhi, Delhi, India;1. School of Earth and Environmental Sciences, University of Portsmouth, Burnaby Bldg., Burnaby Rd., Portsmouth PO1 3QL, UK;2. Department of Applied Geology, Indian School of Mines, Dhanbad 826004, India;1. School of Earth Sciences and Resources, China University of Geosciences, Beijing, 29 Xueyuan Road, Beijing 100083, China;2. Centre for Tectonics, Resources and Exploration, Department of Earth Sciences, University of Adelaide, SA 5005, Australia;3. Department of Earth System Sciences, Yonsei University, Seoul 03722, Republic of Korea |
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| Abstract: | The Bastar craton in central India, surrounded by cratonic blocks and Paleoproterozoic to Neoproterozoic orogenic belts, is a window to investigate the Archean-Paleoproterozoic crustal evolution and tectonic processes. Here we propose a new tectonic classification of the craton into the Western Bastar Craton (WBC), Eastern Bastar Craton (EBC), and the intervening Central Bastar Orogen (CBO). We present petrologic, geochemical and zircon U-Pb, REE and Lu-Hf data from a suite of rocks from the CBO and along the eastern margin of the WBC Including: (1) volcanic successions comprising meta-andesite and fine-grained amphibolite, representing arc-related volcanics along a convergent margin; (2) ferruginous sandstone, in association with rhyolite, representing a volcano-sedimentary succession, deposited in an active trench; and (3) metamorphosed mafic-ultramafic suite including gabbro, pyroxenite and dunite invaded by trondhjemite representing the section of sub-arc mantle and arc root adjacent to a long-lasting subduction system. Petrologic studies indicate that the mafic-ultramafic suite crystallized from an island arc tholeiitic parental magma in a suprasubduction zone environment. The chondrite-normalized and primitive mantle normalized diagrams of the mafic and ultramafic rocks suggest derivation from MORB magma. The mixed characters from N-MORB to E-MORB of the studied samples are consistent with subduction modification of a MORB related magma, involving partial melting of the metasomatized mantle wedge. Our zircon U-Pb age data suggest that the cratonic nuclei was constructed as early as Paleoarchean. We present evidence for active subduction and arc magmatism through Mesoarchean to Neoarchean and early Paleoproterozoic, with the trench remaining open until at least 2.3 Ga. Two major crust building events are recognized in the Bastar craton: during Mesoarchean (recycled Paleoarchean subduction-related as well as juvenile/depleted mantle components) and Neoarchean (accretion of juvenile oceanic crust, arc magmatism including granite batholiths and related porphyry mineralization). The final cratonization occurred during latest Paleoproterozoic, followed by collisional assembly of the craton and its incorporation within the Peninsular Indian mosaic during Mesoproterozoic. In the global supercontinent context, the craton preserves the history of Ur, the earliest supercontinent, followed by the Paleo-Mesoproterozoic Columbia, as well as minor thermal imprints of the Neoproterozoic Rodinia and associated Grenvillian orogeny. |
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| Keywords: | Geochemistry Zircon U-Pb geochronology and Lu-Hf isotopes Crustal evolution Tectonic implications Bastar craton |
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