A probable mechanism of the formation of hydrocarbon deposits in the intraplate deformation area of the Indian Ocean’s lithosphere

Most of the hydrocarbon fields in the oceanic and thinned suboceanic crust are associated with deep-seated faults. This fact might be caused by methane formation under the serpentinization of the upper mantle rocks and its transfer to the sedimentary cover with hydrotherms. The northern part of the Indian Ocean deformation zone may be of considerable promise for the formation of deposits of such genesis. This is favored by the occurrence of the long-living hydrothermal activity over the deep-seated faults and by quite the thick sedimentary cover (over 1 km). In the course of cruise 32 of the R/V Akademik Kurchatov , a buried anticline formation with an acoustic anomaly of the bright-spot type was discovered 450 km southwards from Sri Lanka Island. This may point to the presence of a hydrocarbon accumulation in the sedimentary cover.