Neogene paleoceanographic events in the tropical Indian Ocean: evidences from quantitative planktonic foraminiferal analyses and isotopic record

Detailed quantitative analyses of planktonic foraminiferal assemblages from DSDP Sites 214, 216 and 217 (Nineryeast Ridge) were carried out to determine the nature of fauna! turnover during the Neogene in the tropical Indian Ocean. The abundance distribution of dominant species indicates close similarities in faunal assemblages of low-latitude regions of the Pacific and Indian Ocean. Quantitative planktonic foraminiferal data integrated with isotopic record reveal intervals of major paieoceanographic events during 22 Ma, 14 Ma, 12 Ma-10 Ma, 6.2 Ma-5.2 Ma and 1.8 Ma. The intervals of major faunal turnover observed reflect global climatic and paleoceanogiaphic events coincident with regional tectonism.