Correlation of late Cenozoic marine sections in Andaman-Nicobar, Northern Indian Ocean, and the equatorial Pacific

Abstract

A large number of overlapping stratigraphic sections exposed on the Andaman-Nicobar Islands, Northern Indian Ocean, contain an almost complete Late Cenozoic (Early Miocene to Quaternary) sequence of tropical planktonic foraminiferal zones. A scheme of twenty zones is based on the ranges of planktonic foraminifera; the zones are defined and discussed in relation to the proposed Andaman-Nicobar stages of Srinivasan (1977b). Stratigraphic ranges of the planktonic foraminiferal species allow establishment of 24 datum levels useful for intra- and interregional correlations. Many of the Andaman-Nicobar datum levels are comparable with those established for the equatorial Pacific and are thus important for interregional correlation. The stratigraphic ranges of several species such as Globigerinatella insueta, Globigerinoides conglobatus, Globoquadrina conglomerata and Protentella bermudezi are significantly different from those reported from the equatorial Pacific. The ranges of these species are discussed in detail.