The clay size fraction of the sediments from ODP Site 758 located in the southern Bay of Bengal on top of the Ninetyeast Ridge were studied to better understand South Asian Monsoon induced silicate weathering over the last 27 million years. The radiogenic Sr, Nd and Pb isotope data were measured by multi-collector ICP-MS and the the clay mineral abundances were calculated from X-Ray diffraction measurements. The age model used here incorporates age constraints from both ODP Site 758 and new data from a new multiple hole drill site nearby (International Ocean Discovery Program Site U1443).

Clay mineral abundances in weighted peak area percentage.The repeatability of the semi-quantitative clay mineral measurements was approximately 2%.