Maastrichtian Dinoflagellates and Palynomorphs from Subsurface Deccan Inter-Trap Sediments, Khandala-Ashta Area, Wardha District, Maharashtra

Abstract

A 164 m thick Deccan volcano sedimentary sequence comprising five flows, separated by four inter-Trap beds and overlying the Lameta Formation, has been encountered in borehole KA-I , drilled by the Directorate of Geology and Mining (DGM) for the coal exploration in Khandala-Ashta area of Wardha District, Maharashtra. Of these, the inter trap between the two lowermost flows has yielded a rich spore-Pollen assemblage that is dominated by angiosperms and pteridophytes. The presence of palynotaxa such as Azolla cretacea, Ariadnaesporites sp., Gabonisporis vigourouxii, Triporoletes reticulatus and Aquilapollenites bengalensis, suggests a Late Cretaceous (Maastrichtian) age for the sediments. The palynomorphs are associated with a rich dinoflagellate assemblage mostly comprising of Palaeoperidinium and Selenopemphix. The study indicates that the changing climatic and depositional scenario owing to Deccan volcanic eruption has possibly offered the suitable ecological niche for the first appearance of dinoflagellates and gradual domination of the angiosperm flora in the non-Marine ecosystem during Late Cretaceous in India.