Geological Controls on Natural Gas Distribution In Bottom Sediments of the Continental Margin of the East Siberian Sea and Arctic Ocean

Bottom sediments of the geostructures along the continental margin of the East Siberian Sea and adjacent SE sector of the Arctic Ocean contain methane and its homologues in concentrations of 0.0007–0.1732 and 0.00001–0.03553 cm3/kg (in total); hydrogen and helium, 0.0007–0.5955 and 0.0011–0.2092; hydrogen sulfide, 0–0.0096; and carbon monoxide and dioxide, 0.0016–0.0975 and 0.09–15.54 cm3/kg, respectively, as well as argon, oxygen, and nitrogen in contents of 0.24–0.63, 0.1–3.2 and 76.5–96.4%. The established variability of isotope composition values of δ13C-CH4, C2H6, and CO2 (–60.2…–36.0, ‒26.2…‒16.8, and –27.8…–18.0 ‰) indicates the development of polygenetic natural gases in bottom sediments of the region. Moreover, the distribution of gases across the area and the section as a whole depends on the complex influence of the main gas-controlling factors: composition and organic saturation of the bottom and underlying sediments, the coal-bearing and oil-gas potential of the region, fold and fault tectonics, geostructural setting and magmatism, tectonomagmatic and seismic activity, depth of sediment bedding, and geocryological and other conditions for natural gas accumulation or degassing. Based on the data obtained, maps of the gas saturation distribution of bottom sediments in the region were constructed.