Distribution of Phosphorus and Phosphatisation along the Western Continental Margin of India

Phosphate content in the bulk sediments range from 0.02 to 2.17% and on carbonate free basis it varies from 0.03 to 6.57%. The partition studies indicate that contribution from the acid resistant detrital minerals (HCl insolubles) is negligible. In the inner shelf, the phosphorus is mainly associated with iron (as ferric-phosphate?) and organic carbon. In the outer shelf/slope its association with carbonate suggests its authigenic/diagenetic origin. This is also supported by X-ray diffraction studies wherein the apatite peak is revealed in some samples. In general, sympathetic relationship of phosphorus with organic carbon in the study region indicates genetic relationship between these two elements, which is an important condition for phosphatogenesis. Further, these studies suggest that the outershelf/slope region between Bombay and Quilon is the promising area for detailed exploration for phosphorite deposits.