Shallow and submarine identifications of gas hydrate in the Makran accretionary prism, northern Arabian Sea

The Makran accretionary prism located in the northern Arabian Sea is formed by the subduction of the Arabian plate beneath the Eurasian plate in a northerly direction at low speed and low angle,and there are abundant gas hydrate resources in the accretionary prism. Based on the high-resolution multi-channel seismic data,sub-bottom profile and multi-beam echo sounding data acquired by China in 2019, combined with the former investigation results,this paper discusses the shallow and submarine identifications of gas hydrate in the Makran accretionary prism. The seismic identifications mainly include bottom simulating reflector(BSR)and acoustic blank zone. The topographic and geomorphic signs include submarine pockmark,submarine slump,mound,mud volcano and cold seeps system. The water body signs mainly is flare. Gas hydrate samples have been drilled at the stations with water depth of 1000 m and 2900 m respectively. The abundant hydrate identifications of Makran accretionary prism may be related to the low velocity and low angle subduction geological background,which makes the hydrate identifications in this area show the characteristics of active continental and passive continental margins. Based on the distribution characteristics of identifications in the study area,the anticlinal ridges and theiradjacent areas in the central and western parts of accretionary prism are the gas hydrates prospective areas.