Published:January 01, 2015
The Bastar Craton of India is composed of Archaean nuclei of tonalite–trondhjemite–granodiorite gneisses, enveloped by an older granite–greenstone belt (>3000 Ma) with banded iron formation (BIF), and an auriferous younger granite–greenstone belt with BIF. Available geological, geochemical and geochronological data indicate multiple episodes of orogeny with high-grade metamorphism at 3200–3300, 2600–2700, 2100–2200, 1900–2000, 1800–1850, 1500–1600 and 1400–1450 Ma, and continental rifting and basin development marked by emplacement of mafic dyke swarms at c. 2900 (subalkaline mafic dykes; BD-1A), 2480 (high-Mg mafic dykes; BD-1B), 2100 (Fe–tholeiite dykes; BD-2A), 1880 (Fe–tholeiites dykes; BD-2B), 1776 and 1422 Ma. Associations of extensive bimodal volcanics and riftogenic sediments are found in the Neoarchaean and Palaeoproterozoic basins of the craton. Evidence of Palaeoproterozoic (Huronian) glaciation and associated ‘cap carbonate’ followed by deposition of fine clastics with manganese ore is found in the Palaeoproterozoic Sausar Group. The lithological association of the Sausar Group is comparable to the carbonate–tillite association of the Huronian Supergroup, Snowy Pass Supergroup, Transvaal Supergroup and Turee Creek Group. The geological evolution of the Bastar Craton matches that of Western Australia and South Africa. Such similarities can be analysed to develop a unified Palaeoproterozoic assembly for these provinces.
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Precambrian Basins of India: Stratigraphic and Tectonic Context
This Memoir provides a comprehensive review of the Precambrian basins of the four Archaean nuclei of India (Dharwar, Bastar, Singhbhum and Aravalli-Bundelkhand), encompassing descriptions of the time–space distribution of sedimentary–volcanic successions, the interrelationship between tectonics and sedimentation, and basin histories. Studies of 22 basins within the framework of an international basin classification scheme deepen an understanding of the basin architecture especially for cratonic basins. Most Indian sedimentary successions formed as cratonic to extensional-margin rift and thermal-sag basins, some reflecting mantle plume movement, subcrustal heating or far-field stress. This Memoir shows that Phanerozoic plate-tectonic and sequence stratigraphic principles can be applied to the Precambrian basins of large Archaean provinces. The differences between the stratigraphic architecture of the Indian Precambrian and examples of Phanerozoic basin-fill successions elsewhere are ascribed to variable rates and intensities of the controls on accommodation and sediment supply, and changes inherent in the evolution of the hydrosphere–atmosphere and biosphere systems.