Marine Geology and Coastal Surveys for Seabed Mapping and Mineral Resource Evaluation in India – An Overview

Abstract

Off-shore geoscientific studies and systematic mapping of the seafloor, both in Exclusive Economic Zone (EEZ) and Territorial Waters (TW) along east and west coasts in India, started with the acquisition of research vessels R. V. Samudra Manthan in 1983 and two coastal vessels in 1984. Since then Marine and Coastal Survey Division in Geological Survey of India has been acquiring geoscientific data on the sea bed sediments, seabed morphology , mineral resources, geochemistry and geophysical parameters. The three vessels have collected thousands of surface and subsurface samples from the Indian and international waters during their past over 30 years of service to the nation. As the seabed mapping/ reconnaissance had been completed for EEZ (23,05,143 km 2 ) during the first phase of marine geological mapping and exploration by GSI, the compilation and synthesis of this enormous wealth of geoscientific data is now attempted[63 maps from EEZ and 143 maps from TW]. The second phase of detailed marine geological exploration has been launched as ‘National High Resolution Seabed Mapping and Resource Evaluation within EEZ of India and Beyond’ during the flagging off of the newly acquired all-weather modern research vessel RV Samudra Ratnakar flagged off on 23 rd December, 2013 from the Port of Mangalore. Operational strategies such as marine surveys through progressively closer intervals, systematic ocean bottom probing and sampling, prognostication of natural resources based on conventional methods, conceptual modeling, etc.; are finalized for a focused approach for targeting and prioritizing offshore mineral resources within EEZ of India. Placer heavy mineral resources up to a depth of 1-1.5m thickness from the sea floor on the middle shelf have been identified in an area of 764 sq km with a proven reserve of 108 million tons. On the basis of the delineated OGP (~2,40,000 km 2 ) for the present, Focused Offshore Mineral Exploration (FOME) Cruises are planned to be taken up for Rare Earth Elements & Yttrium (REY), Seafloor Massive Sulphides (SMS), phosphorites, lime mud, gas hydrates, carbonate sand etc; onboard R.V. Samudra Ratnakar.