Characteristics of features formed by gas hydrate and free gas in the continental slope and abyssal plain of the Middle Caspian Sea

Abstract

Physicochemical conditions are proper to form gas hydrate and free gas in the Caspian Sea which are considered both for geohazard assessment and future possible source of energy. Gas migration, hydrate formation and decomposition cause different types of features to form in the seabed and sediments which can be affected by geological and physical conditions of sea. In this study, high-resolution marine seismoacoustic profiles were interpreted to investigate features formed by gas hydrate and free gas and assess their characteristics in the continental slope and abyssal plain of the middle Caspian Sea. A mud volcano, gas chimneys, pockmarks, gas pipes, sediment disturbances, a crater, a giant landslide and a big gentle diapir were investigated and reported in the present study. The geological and physical conditions including bathymetry, tectonic activity, sediments supply and water depth are different in the continental slope and abyssal plain, thereby the features of these two environments were compared to understand the effect of different conditions.

Keywords:

• Hydrate
• free gas
• seismoacoustic
• Derbent Basin
• active tectonic

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Authors thank the Iran National Science Foundation (project 96003650) and Russian Foundation for Basic Research (project 17-55-560003) provided financial support for this research in the frameworks of the joint project «Comparative research of fluid dynamics of the Middle and South Caspian sedimentary basins». Also authors thank the Shirshov Institute of Oceanology for providing valuable seismic data in framework of Governmental fund 0149-2019-0006.