Lack of cross-shelf transport of sediments on the western margin of India: Evidence from clay mineralogy

Abstract

The distribution of clay minerals on the inner shelf, outer shelf and in a 6 month sediment trap on the western continental shelf of India has been studied. Marked compositional differences in the inner shelf clays (montmorillonite dominated) and the outer shelf clays (illite dominated) are noted. Inner shelf clay sources are the contemporary rivers draining the west coast of India while the outer shelf clays appear to have been derived from the Indus River. Though fine sediments have been transported long distances along the shelf, cross-shelf transport appears to be minimal. Confirmatory evidence of qualitative differences in outer and inner shelf clays is provided by sediment trap clay mineralogy on the outer shelf. Clay bound pollutant discharge is likely to be confined to the inner continental shelf