Distribution of major and trace elements of a sediment core from the eastern Arabian Sea and its environmental significance

摘要

A sediment core recovered from the southeastern Arabian Sea off the Indian subcontinent was analysed to understand the distribution of major (Fe, K, Mg, Al, Ca and Sr) and trace elements (Mn, Ni, Cu and Co) as well as their environmental significance. According to the results, variation of Fe, K, Mg and Al during early Holocene period is reflective of the strengthened southwest monsoon and resulting fluvial input of terrigenous materials to the study region. The concentration profile of Ca, Sr and total organic carbon during late Holocene reveals increased productivity and coastal upwelling during recent periods. The profile of redox-sensitive metals indicates the role of terrigenous sources in the variation of these elements apart from the scavenging-releasing effects of Fe-Mn-oxides/hydroxides as well as decrease in oxygen level in sediment-water interface from early Holocene to late Holocene period. The study suggests that two factors are predominantly responsible for observed geochemical variations-terrigenous and biological contribution.