Sediment dispersal pattern off the Mahanadi-Nagavali continental shelf, northwest Bay of Bengal

Textural distribution patterns of seafloor sediments from the Mahanadi - Na gavali shelf, northwest Bay of Bengal, are used to evolve a model for the r egional sediment - dispersal system. Mean size trends, standard deviation, skewness and correlation of negative skewness with silt/clay ratios reveal certain patterns, each being specific to an area(s) of shelf. Sediment dist ribution patterns show that the near shore environment is occupied by sand and clayey sand, while the inner and middle shelf regions are covered by sa ndy silt, silty calcareous sand, silty clay, silty sand and sand-silt-clay. The outer shelf is largely covered by clayey silt. Relict carbonate deposi ts are preserved on the outer shelf at similar to 100 m off Rushikulya to B aruva. Palimpsest sediments cover the Sonapurapeta - Bavanapadu shelf at de pths of 0-60 m. Mud dispersal in the study area offshore is caused by transport components along and across the shelf. The Mahanadi-Devi River system is the principal source of sediment for the Mahanadi - Nagavali shelf. The Nagavali and Vam sadhara rivers are a minor source of sediment towards the southern part of the shelf, and their detrital inputs are largely deposited on the shelf adj acent to the river mouths. Sedimentsin the study area are transported and a dvected southward (bottom nepheloid layers ?). The Mahanadi - Nagavali shel f response to the present hydraulic regime is recorded in the, modern sand facies and the offshore mud facies, particularly the silty clays.