Abstract
Based on an analytical review of factual materials, the article discusses the peculiarities of the distribution of gas hydrates in the development zones of mud volcanism of the Mediterranean, Black and Caspian seas, which are direct indications of sedimentary gas complex. A comparative analysis of the composition of hydrate-forming fluids, sources and depths of gas hydrates distribution was performed. The article provides information on gas seeps and pokmarks. The presence of gas seepsand pokmarks in the water column and at the bottom of the Southern Caspian is assumed.