Journal of the Marine Biological Association of India

Volume 39 Issue 1&2

Late Quaternary paleoceanographic features as deduqed from calcium carbonate and faunal changes of planktonic foraminifers in core samples from northeastern Arabian Sea

K. Kameswara Rao, K.V. Jayalakshmy and A.D. Singh

Two pelagic core samples, ARB-52 and ARB-54 from 2240 m and 800 m depths respectively from the Arabian Sea off Bombay were analysed for determining climatic changes during the past 30,000 yr. based on the interpretation of change in calcium carbonate and planktonic foraminifers, with implications on paleoceanography of the Arabian Sea during late Quaternary. Paleoclimatic curve besed on per cent variations of carbonate is substantiated by the faunal characteristics. Low value of cold- water/warm-water faunal ratio was correlated with carbonate maximum. Frequency distribution of 10 selected species showed that 2 species, Globorotalia menardii complex (warm-water species group) and Neogloboquadrina pachyderma (coolwater species) were found to be reliable as climatic indicators. 'Mo faunal zones, Z and Y were observed for the cores. Furthermore, faunal composition of the glacial and post-glacial periods in both the cores showed some similarity to the present-day fauna of the northern Indian Ocean. This faunal affinity suggests that changes in near-surface water temperatures during the last glacial period did not induce major alterations in the fauna and the fact that sea swfaa temperahues were slightly warma in the Arabian Sea during Last Glacial Maximum reinforced the above point of observation. 



Date : 30-12-1997