Methane hydrate in sediments of Lake Baikal

The probability of the gas hydrate occurrence in sedimentary succession of Lake Baikal was predicted based on the analysis of heat flow and bottom top ography of the lake. The lower boundary of gas hydrate distribution in the sedimentary sequence and the thickness of the hydrate-bearing layer were es timated. Multichannel seismic profiling in the Southern and Central basins (1989 and 1992) of the lake using the common-midpoint method revealed seism ic boundaries of the BSR type, which represent most reliable geophysical in dicators of the gas hydrate occurrence. An accumulation of gas hydrates was discovered in turbidite sediments 121 and 161 mbsf by drilling in the Sout hern Basin of Lake Baikal in the framework of the International "Baikal-Dri lling Project" (Hole BDP-97, water depth of 1427 m). This is the first disc overy of methane gas hydrates in freshwater basins. The results of the stud y of core samples performed in several institutions of the Russian Academy of Sciences using the X-ray phase, differential-thermal thermal-volumetric, and chromatographic methods confirmed an inference about the presence of C H4 . 5H(2)O gas hydrates in sediments.