Major, trace, and rare earth elements in the sediments of the Central Indian Ocean Basin: Their source and distribution

Abstract

The distribution maps of elements show that highest concentrations of Mn, Cu, Ni, Zn, Co, and biogenic opal in the surface sediment occurs between 10 degrees S and 16 degrees S latitude, where diagenetic ferromanganese nodules rich in Mn, Cu, Ni, and Zn are present. The studies highlight that the excess element concentration (detrital unsupported) such as Mn, Cu, Ba, Ni, Co, Pb, and Zn have contributed greater than 80% of their respective bulk composition. These excess elements exhibit strong positive correlation with each other suggesting their association with a single authigenic phase such as Mn oxide. Biogenic opal contributes 30-50% of the total silica in the siliceous sediment. Aluminum, Fe, and K have contributed greater than 60 % from terrigenous detrital source compared to their bulk composition. Calcium, Sr, and P depict a common source such as biogenic. Bulk element concentration such as Li, V, Cr, Sc, and Zr are positively correlated with Ti indicating their terrigenous detrital source. REE in these sediments are mostly carried by authigenic phases such as manganese oxide and biogenic apatite