Late Cretaceous to Early Tertiary dinoflagellate cysts from the Krishna-Godavari basin-cyst morphology and review of biostratigraphical dating

N.C. Mehrotra; William A.S. Sarjeant

doi:10.54991/jop.1998.1273

Authors

N.C. Mehrotra Palynology Laboratory, K.D. Malaviya Institute of Petroleum Exploration, ONGC Ltd., 9 Kaulagarh Road, Dehra Dun 248195, India
William A.S. Sarjeant Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, SK, S7N 5E2, Canada

DOI:

https://doi.org/10.54991/jop.1998.1273

Keywords:

Dinoflagellate cysts, Fibrocysta variabilis, Biostratigraphy, Krishna-Godavari basin

Abstract

A restudy of some of the dinoflagellate type material of our earlier work (Mehrotra & Sarjeant, 1987) from well Narasapur-1, Krishna-Godavari Basin has been undertaken, in order to clear up some confusion created by the comments of Garg et al. (1995). The validity of Fibrocysta variabilis as a distinct species is amply demonstrated by further elaborating on its morphological characters, with the aid of some additional specimens from the Narasapur assemblage. Fibrocysta sp. is tentatively retained in this genus, till further specimens permit fuller understanding of its morphology. Our earlier age assignments of samples at various stratigraphic intervals-Late Cretaceous (Maastrichtian: 3621-3624 m, 3643-3649 m, CC-13) and Paleocene (now further refined to Thanetian: 2703-2706 m; including part of CC-10 at 2703 m)-are reaffirmed, utilizing additional information concerning the global ranges of other dinoflagellate species. Data on microforaminifera, spores and pollen are also presented, conforming with and strengthening these dates.