Abstract:

The north of the South China Sea is the important basement of marine hydrocarbon and the first selection region of the gas hydrate investigation in China.Based on the geochemical results of sediments at site HD196 in Dongsha islands, the features of major elements show the tendency of two sections, and just consistent with the change of the ion content of pore water and methane in the sediment. Meanwhile, the change of the ion content of pore waters at the site has the same characteristics as that at other sites where the gas hydrate has been discovered. Furthermore, the geological condition of the region shows that the P-T enviorment, gas source conditions and tectonic settings could provide suitable thermodynamic condition for the formation of gas hydrates in the site. Therefore, there may be gas hydrates below the site, and further work will lead to a breakthrough in the exploration of the gas hydrate.

Key words: gas hydrate, geochemistry, Dongsha Islands, the South China Sea