Upper Palaeocene Calcareous Nannoplankton from Cauvery basin, Southern India

Abstract

Phytoplankton analysis of a 240 meter deep bore hole, located in the Gopurapuram Village north-east of Vriddhachalam in Cauvery basin, revealed the presence of calcareous nannofossils and dinoflagellate cysts in the basal sample, whereas the samples higher up in the sequence yielded only dinocysts. The nannofossils assemblage includes eight genera containing 16 recognizable species. Out of these, Discoaster multiradiatus is discussed to mark the Standard Nannoplankton Zone NP 9 of Upper Palaeocene. The equivalent zone marker taxa of dinocysts, foraminifera and mega-algae also support an Upper Palaeocene age for these sediments.