Composition of Narbada and Tapti estuarine particles and adjacent Arabian Sea sediments

Abstract

Composition of suspended matter collected from Narbada and Tapti estuarine waters and of the sediments from the near-coastal and open shelf and slope regions of the Arabian Sea is reported. Metal/Al ratios, which essentially indicate the clay composition, remain unchanged (within ± 20%) from one end of the estuary to the other and in the near-coastal sediments indicating that the adsorption-desorption reactions are within the scatter (within ± 20%) itself. In the anoxic open shelf and slope regions, Ni, Zn and U are enriched whereas Mn is depleted. Aughigenic deposition of Ni and Zn as sulphides, U in the +4 valence state and diffusion of reduced Mn (Mn⁺²) are the most probable causes. Suspended fluxes of Al, Fe, Mn, Cu, Ni, Zn and U and their deposition rates in the Coastal Arabian Sea Regions during the past 1100 yr are estimated.