Late Artinskian–Kungurian biodiversity of the Sirka area, South Karanpura Coalfield, Jharkhand, India and their palaeoclimatic connotations

Permian deposits are widely distributed in the Indian peninsula and are potential sources of coal and petroleum. This article deals with the reconstruction of the palaeoclimate, palaeovegetation, palaeoecology and depositional settings of Permian strata in Sirka Colliery of South Karanpura Coalfield based on megafloral and palynological investigations. The mega^_ and micro^_floral assemblages reported from coal-bearing strata of the Barakar Formation demonstrate that the late early Permian floras were dominated by Glossopteridales, Cordaitales, Coniferales, Filicales and Peltaspermales in the investigated area. The late Artinskian and Kungurian are assigned to the palynoassemblages I and II, respectively based on their palynoassemblages. The recovered megafloral assemblage showcases a striking diversity of Glossopteridales including 25 species of the genus Glossopteris, and it is devoid of typical Karharbari Formation floristic components, such as Buriadia, Gangamopteris, Noeggerathiopsis, and Euryphyllum. Thus, the megaflora suggests that the upper Barakar Formation is late Artinskian and Kungurian in age, corroborating the age resolved from palynoflora. The megafloral assemblage is dominated by petiolate Glossopteris leaves of intermediate mesh form with acute apices, acute cuneate bases, strong persistent midribs and entire margins. This recommends a moderately warm temperate humid climate during the deposition of these coal beds. The dominance of non-striate bisaccate in lower beds (palynoassemblage I) and an abundance of striate bisaccate pollen grains in upper strata (palynoassemblage II) infer a climate shift from cool temperate to moderately warm humid condition during the late Artinskian- Kungurian transition. The concurrence of thick coal beds with diverse plant assemblages suggests the prevalence of woody forest vegetation adapted to mire habitats during the deposition of the sediments. The presence of Filicales and Peltaspermales also suggests a swampy environmental setting during the accumulation of the studied unit. On a broader scale, this study contributes to the understanding of Permian palaeoclimatic transitions and vegetation dynamics in Gondwana basins, providing insights into the global climatic patterns and ecosystem responses during the Permian. These findings have implications for the broader reconstruction of palaeoenvironments in Gondwana, aiding in the exploration of Permian coal and hydrocarbon resources in similar basins worldwide.