Late Miocene discoasters from Sawai Bay Formation, Neill Island, Andaman Sea, India

Abstract

Twenlyone speciesof discoasters are documented from the East Coast and Nipple Hill section~ of Sawai Bay Formation. Discoaster pentaperforatus is proposed as new and three species are described under open nomenclature. Discoaster berggrenii and Discoaster quinqueramus are the most common forms in the assemblage. The calcareous nannofossil assemblage containing critical Discoaster species suggests assignment to Discoaster berggrenii Subzone (CN9A) of Okada and Bukry (1980), corresponding to lower part of Discoaster quinqueramus zone (NN11) of Martini (1971).