Comparative petrological analysis between the Permian coals of India and Western Australia: paleoenvironments and thermal history

Abstract

Abstract Permian sequences preserved in Western Australian basins (Collie, Perth and Canning) and the Gondwana basins of India (Damodar, Son-Mahanadi, Pench-Kanhan and Godavari Valley) have similar stratigraphic succession, faunal and floral assemblages, coal types and rank, and structure. As for coal types, petrographic analyses of Indian coals indicate that vitrinite, liptinite, inertinite and mineral matter content ranges from 37 to 56%, 8 to 14%, 24 to 35% and 12 to 18%, respectively. Western Australian coals show contents of vitrinite, liptinite, inertinite and mineral matter ranging from 31 to 67%, 6 to 10%, 20 to 57% and 6 to 7%, respectively. As for rank of coal, in India, high rank coals (Rvmax = 0.70–1.67%) occur in the Damodar Valley Basin. In this basin vertical rank gradients are higher, and uplift and removal of cover has occurred to a greater extent than in the other Gondwana basins of India. Some coals from Pench-Kanhan Valley Basin (Rvmax = 0.72–1.02%) and Son Valley Basin (Rvmax = 0.70–1.10%) have high reflectance values. Coals from other Gondwana basins occur at shallow depths and are of sub-bituminous rank (Rvmax = 1%) compared to other coals in the basin. Thus, the type and rank of the Permian coals indicate a similar depositional and thermal histories for the basin studied in India and Western Australia. This is consistent with the view that India and Western Australia were in close proximity before the break up of Gondwanaland.