Proterozoic Stratigraphy of Southern Indian Cratons and Global Context

Abstract

Abstract Precambrian cratons in India host large intracratonic basins with thick Proterozoic successions ranging in age from c.1900 to c.700 Ma, though the tempo of sedimentation and age range vary from basin to basin. The stratigraphy of the major basins in southern India including Cuddapah–Kurnool, Pranhita–Godavari (P–G) valley, Chattisgarh, Kaladgi–Badami, and Bhima basins is reviewed in this chapter in the light of recent sedimentological studies. Earlier attempts of intrabasinal and regional correlations are examined in the light of recently available geochronological data. Unconformity bound sequences in each of these basins show cyclic sedimentation where early rifting stage with coarse alluvial fan, fan-delta, and fluvial deposits, is followed by extensive tidal–intertidal to shallow marine mixed siliciclastic-carbonate sedimentation, with occasional change-over to deep-water carbonate platform or turbidite deposition, during the basin subsidence stage, and apparently influenced by major relative sea-level changes. The oldest sedimentation beginning c.1900 Ma is recorded in the Cuddapah basin in the Eastern Dharwar craton with two cycles of sedimentation in the Paleoproterozoic roughly coinciding with global proliferation in passive margin sedimentation. The older sedimentary sequence in the Kaladgi–Badami basin along the northern margin of the western Dharwar craton probably also started at the same time. The oldest sequence in the P–G valley basin is c.1680 Ma, with at least two more cycles in the Mesoproterozoic, and sedimentation closing in a final cycle dominated by fluvial sedimentation in the Neoproterozoic. Bulk of the sedimentation in the Chattisgarh and other satellite basins in the Bastar craton took place between c.1450 and 1000 Ma, with the development of stromatolite-bearing as well as deep-water carbonate platforms. Precise tectonic models of internal deformation of some of the Paleoproterozoic–Mesoproterozoic sequences, prior to deposition of younger groups, are an unresolved issue, but there are records of subduction-related activity both in the upper Paleoproterozoic and Mesoproterozoic outboard of the Indian cratons, which probably had little influence on the then passive margin sedimentation constituting bulk of the intracratonic basin fills in southern Indian block. Docking of the Eastern Ghats orogenic belt with supposed connections with parts of Antarctica (or Australia) during the amalgamation of Rodinia, along Dharwar–Bastar craton margins led to the cessation of passive margin Neoproterozoic sedimentation as recorded in the Kurnool basin and the P–G valley basin, whereas suturing of the North Indian cratonic block and the southern Indian block led to demise of the sea lane north of Bastar and Dharwar cratons.