Origin of the Neoarchean granites from the southeastern margin of the Western Ghats greenstone belt, Dharwar Craton: Implications for crustal evolution in the Western Dharwar Craton

• Published in: Journal of Earth System Science Vol. 131; no. 4; p. 240
• Main Author: Boraiaha, Chandan Kumar
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 19.11.2022; Springer Nature B.V
• Subjects: Belts; Biotite; Cratons; Earth and Environmental Science; Earth Sciences; Geochemistry; Geology; Granite; Lava; Magma; Melting; Metamorphism; Mica; Muscovite; Plate boundaries; Quartz; Rhyolites; Rocks; Sediments; Size distribution; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Volcanic rocks; Volcanoes; Western Ghats; India; Narasiparvatha Formation; crustal evolution; crystal size distribution (CSD); Peraluminous granites; WDC
• ISSN: 0973-774X; 0253-4126; 0973-774X
• DOI: 10.1007/s12040-022-01976-0

The field, crystal size distribution, mineral-chemistry and bulk-rock geochemical study on the felsic magmatic rocks (granite and associated rhyolites) of the Western Ghats belt, Dharwar Craton, has been presented for the first time in this contribution. These Neoarchean felsic magmatic rocks occur as massive plugs and lensoidal bands running for several meters to kilometres, with a general trend of NNW–SSE. These rocks are characterised by the ubiquitous presence of biotite and muscovite and are devoid of amphiboles. These rocks show evidence of textural coarsening but show no evidence of magma mixing or assimilation. The petrogenetic studies indicate that the partial melting of tonalite–trondhjemite–granodiorite (TTG) crust together with a considerable amount of Al-rich sediments has resulted in the peraluminous granitic melt source. This melt, subsequently, was mobilised to shallow crustal levels where it was emplaced along the axial planes of F1 folds before it was erupted on to the surface, giving rise to rhyolites. The similarities in the field, mineralogical and geochemical characteristics amongst ~2.61 Ga old felsic volcanic rocks of the different greenstone belts in the Western Dharwar Craton (WDC) suggest that they were all derived from the partial melting of >3.1 Ga felsic crust with a minor input of metasedimentary units at mid-crustal levels. The felsic volcanic rocks show evidence of emplacement in the active plate boundary, the interior of WDC.