TECTONIC SUBSIDENCE ANALYSIS OF GONDWANAN BASINS IN PENINSULAR INDIA – JHARIA AND RANIGANJ BASINS OF EASTERN INDIA

The Peninsular India, once constituted East Gondwana, received sediments that started in the latest Carboniferous, perhaps through the relaxation of Gondwana, and ceased in the Jurassic through the break up of India from the rest of Gondwana. These thick sedimentary strata are preserved in many discrete fault-bounded basins. The origin, nature, and timing of subsidence in these basins are poorly understood. The Jharia and Raniganj basins, part of the Damodar Valley Basin system of Eastern India, preserve thick Gondwanan sequences, allowing one to study these enigmatic basins. Litho- and bio-stratigraphic data compiled from published literature are utilized to construct tectonic subsidence curves to better understand the basin's evolution history. Tectonic subsidence was minimal during the Talchir deposition (Gzhelian-early Sakmarian (latest Carboniferous-Early Permian)). Rapid subsidence started and peaked in the Early Permian (Sakmarian) during coal-rich Barakar deposition and continued through the Middle and Late Permian (Guadalupian-Lopingian) deposition of Barren Measures and Raniganj formations. Magnitudes and patterns of subsidence curves conform with an intracratonic rift basin that developed during the Gondwanan rifting. Future works on other Gondwanan basins of Peninsular India would provide insight into a better understanding of East Gondwana's break-up and rift-drift stages.