Study of sub-surface sediments from northern Indian Ocean: Oceanic responses to climatic changes

Abstract

The mean diameter and variation in isotopic composition (delta sup(18)) in thest of Orbulina universa d'Orbigny have been measured in a sediment core collected from 3869 m water depth near the Carlsberg Ridge, northern Indian Ocean. It has been found that changes in test's mean diameter precede isotopic responses by about 1000 years in the samples from this core. The distribution of illite and smectite-suggests that fresh water discharge from the River Indus, due to ice melting in the Himalayan region, played a more important role in reducing salinity than did melting ice in the Antarctic region or the intrusion of low salinity water from the Bay of Bengal