Exploration of the continental margins of India

Abstract

In mid 1970's the National Institute of Oceanography, Goa, India prepared a plan for systematic regional, geological and geophysical surveys of the continental margins of India. This involved over 75,000 km of underway (bathymetric, side scan sonar, magnetic, gravity and seismic) surveys on tracks about 20 km apart, and collection of about 1500 seabed samples at about 10 to 20 km spacing. It was anticipated that the entire programme would require 22 ship's months. This programme received considerable impetus from sponsored surveys of other organizations, chiefly the oil industry, ports and harbours as well as industries disposing of their effluents in the marine environment. By now the entire western continental shelf and a large part of the continental slope have been covered by about 68,314 km bathymetric surveys, 12,720 km side scan sonar surveys 46,222 km magnetic surveys, 27,200 km seismic surveys (including 5, 489 km multichannel seismic), and 9,065km gravity surveys. Approximately 1500 seabed samples have been collected. These surveys, besides providing basic information on the morphology, sediments, and geochemistry of the sediments of the western continental margin of India, have also led to the estimation of resources of offshore ilmenite placers and low grade phosphorite deposits. The data collected are proposed to be depicted in a series of maps showing the morphology, sediments and geochemistry of sediments.