Seafloor Geophysical Study in Search of Gas Hydrates/Gas Related Evidences in the Deep Waters of the Western Continental Margin of India

Abstract

New data have been collected using the multibeam echosounder (Hydrosweep) and high resolution sub-bottom profiler (Parasound) systems in deep water of the Western Continental Margin of India (WCMI) during the 41st cruise of R/V Academic Boris Petrov from 17 to 26 November, 2006. The six meters gravity coring along with CTD (Conductivity-Temperature-Depth) measurements are also carried out. Two sites in the Saurashtra and Kerala-Konkan offshore basins have been covered to find out features related to gas hydrates during this short cruise. High resolution multibeam echosounder and, sub-bottom profiling delineate the fine-scale structure of the sedimentary layer of about 50-100 m thickness below the seafloor. Gravity corer is operated at five stations, out of which four gravity cores of more than 5 m length are recovered successfully. Gas and pore waters from cores have been collected for performing the laboratory studies. The Rosette system is used for temperature and salinity measurement in the water columns. The gravity cores collected on sites show the evidence of sediment fluidization and contain certain amount of gas. The gas is collected from sediments using the technique developed in the V.I.Vernadsky Institute of Geochemistry and Analytical Chemistry for the chemical and isotopic analysis for future research. The preliminary results show that the continental slope and rise of the oceanic margin of the Western India are prospective for exploration of gas hydrate. The more definite conclusion can be drawn after carrying out laboratory studies.