Archean crustal evolution of the Bundelkhand Craton: evidence from granitoid magmatism
Published:December 14, 2020
Vinod K. Singh, Sanjeet K. Verma, Pradip K. Singh, A. I. Slabunov, Sumit Mishra, Neeraj Chaudhary, 2020. "Archean crustal evolution of the Bundelkhand Craton: evidence from granitoid magmatism", Archean Granitoids of India: Windows into Early Earth Tectonics, S. Dey, J.-F. Moyen
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This study presents petrological and geochemical data on Neoarchean granitoids from the northern and central parts of the Bundelkhand Craton to discuss its crustal evolution and tectonic history. The study deals with two granitoid suites, i.e. tonalites–trondhjemites–granodiorites (TTG) and sanukitoids. TTGs are characterized by high SiO2, Na2O and mostly low to moderate Mg#. They display enrichment in light rare earth elements, low to moderately fractionated heavy rare earth elements (HREE) and low Sr/Y ratios, suggesting their high-HREE character or low-pressure origin from melting of a mafic protolith. The sanukitoid samples show relatively low SiO2, high K2O (2.1–4.6 wt%), Pb, Sr and Ba, and moderate to low Mg#, Cr, Ni. These granitoids probably generated from partial melting of hydrous mafic rocks followed by interaction with a mantle peridotite. Geochemical characteristics, tectonic discrimination using ratios like (Ce/Pb)PM, (La/Nb)PM and (Th/Nb)PM and regional rock association suggest that the Neoarchean TTGs and sanukitoids were emplaced in a subduction setting. Combining the existing knowledge base, a schematic model for generation and evolution of crust from Paleoarchean to Neoarchean has been proposed for the Bundelkhand Craton.
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Archean Granitoids of India: Windows into Early Earth Tectonics
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Granitoids form the bulk of the Archean continental crust and preserve key information on early Earth evolution. India hosts five main Archean cratonic blocks (Aravalli, Bundelkhand, Singhbhum, Bastar and Dharwar). This book summarizes the available information on Archean granitoids of Indian cratons. The chapters cover a broad spectrum of themes related to granitoid typology, emplacement mechanism, petrogenesis, phase-equilibria modelling, temporal distribution, tectonic setting, and their roles in fluid evolution, metal delivery and mineralizations. The book presents a broader picture incorporating regional- to cratons-scale comparisons, implications for Archean geodynamic processes, and temporal changes thereof. This synthesis work, integrating modern concepts on granite petrology and crustal evolution, offers an irreplaceable body of reference information for any geologist interested in Archean Indian granitoids.