Classification of the Paleoproterozoic Gulcheru Formation: Implications on Early Paleogeographic and Tectonic Evolution of the Cuddapah Basin, India
Journal of the Geological Society of India
The Papaghni sub-basin of the Cuddapah basin is an arcuate NW-SE trending intracratonic basin, stretching from Kurnool in the NW to Guvvalacheruvu in the SE, in southern peninsular India. Despite of large number of researches, an understanding of the evolution of the basin is still elusive. The sub-basin preserves records of repeated opening and closing of Paleoproterozoic rifts along the zone of NW-SE trending axis in the East Dharwar craton. Present study was carried out along the southwestern margin of the Papaghni sub-basin, in and around Tadpatri-Gooty-Dhone area, where the successive litho-units are represented by two major unconformity-bound sequences. Each of these sequences are characterized by a distinctive set of litho-assemblage, deposited under diverse tectonic environments with highly variable modes and tempos of sedimentation in an extensional basin. The basin initiated at about 2 Ga and shortly evolved into a shallow sea, with development of wide siliciclastic shelf in an open marine condition, the Gulcheru Formation. Gradually, with time the siliciclastic shelf was replaced by an extensive stromatolitic carbonate platform, the Vempalle Formation. Dedicated fieldwork exemplifies that the initial basin-fill is characterized largely by several cycles of simple, but amalgamated and stacked fanglomerates (alluvial fan to fan-delta) systems developed from several single stream breaches onto the proximal setting of the basin, in a syn-rift setting. These fanglomerates display a fining upward sequence, which progressively passes up to high-energy coastal, tide-storm dominated shelf environments of post-rift setting. This study justifies the subdivision of the Gulcheru Formation into two formal lithostratigraphic members, the Daditota Member and the Karvipalle Member. The Daditota Member directly overlies the granitoid basement and grades upward to Karvipalle Member. Karvipalle Member, comprising predominantly of medium to finegrained, reddish brown and white quartz arenites of stable shelf deposits, distinctly differs from the conglomerate and very coarsegrained mass-flow dominated deposits of the Daditota Member. The Vempalle Formation overlies the Gulcheru Formation with a gradational contact and consists of stromatolitic dolomite, oolite and shale, developed in a ramp type carbonate platform setting. Gradual transition from siliciclastic to carbonate sequence points to passive margin setting developed during the breakup of the supercontinent Kenorland. Disposition of proximal to distal sequences and northeastern, eastern and southeastern paleocurrent of the sequences advocate a NW-SE shoreline and eastern paleoslope of the basin.
Majumder, Tuasha and Patranabis-Deb, Sarbani, "Classification of the Paleoproterozoic Gulcheru Formation: Implications on Early Paleogeographic and Tectonic Evolution of the Cuddapah Basin, India" (2020). Journal Articles. 183.