Geological survey of India is one of the pioneer organizations involved in exploring the oceans around India. Marine and Coastal Survey Division [M & CSD] of GSI [erstwhile Marine Wing (MW) / Offshore Mineral Exploration & Marine Geology (OME & MG)] has started coastal and marine surveys in a miniscule manner way back in early nineteen seventies by survey and mapping of selected parts of coastal waters using country boats and other small fishing crafts. The work mainly confined to collection of surface sediment samples and spot bathymetric data. With the acquisition of one ocean going vessel R.V. Samudra Manthan in 1983 and 2 coastal launches R.V. Samudra Kaustubh and R.V. Samudra Shaudhikama in 1984, GSI commenced systematic survey of the sea bed within Exclusive Economic zone (EEZ). In pursuance of the Charter of Geological Survey of India, the main emphasis of marine survey has been on seabed mapping and exploration for non-living resources in the offshore sector in the EEZ and in the international waters. The various thrust areas identified to cater to the needs and challenges of the Nation and fulfilling the short term and long term socio-economic needs. They encompass baseline data collection (geological & geophysical), assessment of offshore mineral potential, geochemical scan for hydrocarbons, basic research and development in furtherance of understanding of various processes of earth science, industrial and port development, evaluation of natural processes and thereby mitigating the damages due to natural hazards, historical and archaeological evolution of coastal areas.
Marine and Coastal Survey Division (M&CSD) of Geological Survey of India has carried out 738 cruises within the EEZ of India since 1983 using three Research Vessels: RV Samudra Manthan, RV Samudra Shaudhikama and RV Samudra Kaustubh to generate baseline marine-geoscientific data. Seabed mapping carried out so far lead to exploration for economic heavy minerals (HM) in the Territorial Waters (TW) of India which has resulted in delineation of promising resources. Similarly, estimation of construction grade sand off Kerala has been delineated. Further, vast resources of high grade calcium carbonate mud (Lime Mud) occur along the outer continental shelf and continental slope off Gujarat and Maharashtra are being evaluated in detail. The seabed mapping on reconnaissance scale had been completed for an area of 19,84,578 km2 out of the total EEZ area of 20,14,900 km2 during the first phase of marine geological mapping by GSI. The compilation and synthesis of this enormous wealth of geoscientific data helped to identify areas for regional exploration which is now being attempted. In order to meet the ever growing demand for mineral resources, the delineation of Obvious Geological Potential (OGP) Areas for offshore minerals in EEZ of India was considered imperative for strategizing future course of detailed marine geological studies and prioritizing the concerted action plans for offshore mineral exploration. On the basis of the delineated offshore OGP, Focused Offshore Mineral Exploration (FOME) Cruises are being taken up for Polymetallic Deposits (PMD) that include REE, Co, PGE, Gold etc, phosphorites and lime mud, heavy mineral placers and construction grade sand.
