Marine sediments and palaeoclimatic variations since the Late Pleistocene: An overview for the Arabian Sea

Abstract

A large number of surfacial and sub-surface sediments from the Arabian Sea have been studied to enhance our understanding of palaeoclimatic variations over the Indian region. Bsically the surficial sediments have been studied for their living (foraminifera) and non-living (minerals) components to identify the parameters which can be used to reconstruct palaeoclimate. It is concluded that for the latter the important components are carbonate content, the mean size of quartz grains, content of felspars and the diagenetic texture of limestone. In benthic foraminifera, dimorphic ratios, morphometric variations and barnacle fluling on relict foraminifers are found to be useful indicators of climate, as are morphology (size) and percentage of planktonic specimens in the total assemblage in addition to oxygen isotope variations in planktonic foraminifera. Using sub-surface sediments as the source, and the above techniques as tools, a number of palaeoclimatic reconstructions have been made for the Arabian Sea Region. These studies dealing mostly with sea level changes and the palaeomonsoon are classified in Stream 1 and Stream 2 according to the objectives of Past Global Changes (PAGES) studies under the International Geosphere Biosphere Program (IGBP)