Floral Diversity of South Karanpura Basin, Jharkhand, India and their Palaeoclimatic Implication with Special Reference to Palaeoenvironment

Abstract

Abstract The palaeofloristic study of Gondwana sediments recovered from Religara area, South Karanpura Basin illustrates the macrofloral diversity in the area. Three distinct megafloral assemblages I, II, III are reported from freshly exposed coaly shale and carbonaceous shale layers of lower Barakar, upper Barakar and Raniganj formations of the basin. The assemblage comprises 72 species and thirteen genera of which 28 are newly reported species, which clearly exemplifies the macrofloral diversity over Permian Period in the studied area. The retrieved floral assemblages justified the existence of two interrelated ecosystems i.e., terrestrial and marshy. A gradual shifting of leaf morphology in reticulate leaves of order Glossopteridales illustrates biostratigraphic age as well as the shifting of climate during the deposition of sediments. The dominance of narrow mesh Glossopteris flora with the presence of typical Karharbari flora in the lowermost fossil horizon, illustrating the biostratigraphic age as late Artinskian (lower Barakar Formation). Likewise, the middle and upper floristic zones are dominated by Glossopteris of intermediate mesh form and broad mesh form suggesting biostratigraphic age as Kungurian (upper Barakar) and Wordian-Changhsingian (Raniganj) respectively. Deposition of in-situ Vertebraria depicts the autochthonous coal deposits and existence of some patches of palaeosol in the investigated location. The present investigation aims to infer the biostratigraphy, palaeoclimate, palaeoenvironment, palaeovegetational reconstruction of the basin during late Artinskian –Kungurian and Wordian- Changhsingian times.