Variation of paleo-productivity and terrigenous input in the eastern Arabian Sea during the past 100 ka

Abstract

A 4.1m long sediment core from the Eastern Arabian Sea (EAS) is studied using multiple geochemical proxies to understand the variation of productivity and terrigenous matter supply during the past 100 ka. The temporal variation in element concentration and fluxes of CaCO3, organic carbon (Corg) and Barium excess (Baexc), together, in general indicate a higher productivity during the cold climate and highest during the Last Glacial Maximum (LGM) in particular. This cold climate-increased productivity coupling may be attributed to the shoaling of nutricline due to enhanced convective mixing resulting from the intensified winter monsoon. Increased linear sedimentation rates and fluxes of Al, Fe, Mg, Ti, Cr, Cu, Zn, and V during the cold period also suggest increased input of terrigenous matter supporting intensified winter winds. However, the presence of large abundance of structurally unsupported elemental content (e.g.: Mg-86 percent, Fe-82 percent and Al-53 percent) indicate increased input of terrigenous material which was probably enhanced due to intense winter monsoon.