Palaeofloristics of Lower Gondwana exposure in Hingula area, Talcher Basin, Odisha, India: an inclusive study on biomarkers, megafloral and palynofloral assemblages

Abstract

ABSTRACT This paper deals with an integrated work on the study of megafossils, palynoflora, and biomarkers in the Hingula Opencast Coal Project, Talcher Basin, Odisha, India. The macrofloral assemblage recovered from the lower grey shale bed of the investigated outcrop comprises Schizoneura gondwanensis, equisetaceous stem (Equisetales), Neomariopteris hughesii (Filicales), 19 species of Glossopteris, Vertebraria indica and stem cast (Glossopteridales). The megafloral assemblage and lithology (fine to medium-grained feldspathic grey shale) of the litho-column strongly suggest that the sediments belong to the Barakar Formation of late Early Permian (Artinskian-Kungurian) age. The palynofloral assemblage identified from the upper carbonaceous shale bed of the same outcrop is characterised by the dominance of Striatopodocarpites spp. and sub-dominance of Faunipollenites spp. Stratigraphically significant taxa of this palynoassemblage show its affinity towards the Late Permian (Wordian-Capitanian) age. The first-ever biomarker study of Talcher Basin has been undertaken as a part of the present investigation, which reveals the occurrence of short to long-chain hydrocarbons, indicating the presence of aquatic, microbial, and higher plant input. The predominance of n-C25 in most of the samples indicates moderate-to-high water levels. Similarly, the prevalence of pristane over phytane depicts suboxic to oxic basin conditions during deposition.