DEPOSITION OF MN-CU-NI-ENRICHED SEDIMENTS DURING GLACIAL PERIOD IN THE CENTRAL INDIAN BASIN

Two siliceous sediment cores collected from the Central Indian Basin h ave been analysed for organic carbon, biogenic silica, Al, Mn, Ni and Cu content. The concentrations of Mn, CU and Ni showed one order of ma gnitude variation (an enrichment by a factor of 20) down the core, wit h a pronounced maximum at depths of 78 cm and 26 cm, corresponding to 390 +/- 80 and 320 +/- 60 kyr BP, respectively. The depthwise variatio n of Mn content matches closely that of cold water subtropical fauna, with both the parameters showing inverse relationship with organic car bon. The observed variations are due to changes in the palaeo-oceanogr aphic conditions.