Characteristics and controlling factors of submarine fluid escape in Tethys tectonic domain

Seabed fluid escape may significantly change the seafloor topography, resulting in some geomorphic features such as pockmarks, mud volcanoes and cold seep plumes. The Tethys tectonic domain, the most hydrocarbon-rich domain in the world, hosts substantial fluid escape-related structures that can act as good indicators for offshore hydrocarbon exploration and global climate changes. Based on previous researches of major sea areas in the Tethys tectonic domain, this paper systematically summarized the characteristics of the seabed fluid flow, which shows that the seabed fluid escape activities of the Tethys tectonic area are mostly distributed in passive continental margins and back-arc rift basins. Seafloor manifestations of fluid escape including submarine cold seeps, pockmarks and mud volcanoes, are widely distributed in the Mediterranean Sea, the Black Sea and the South China Sea, however, massive carbonate-related structures are the prominent seabed fluid escape features in the Persian Gulf and the northwestern shelf of Australia. Seabed fluid flow is a dynamic process in the Tethys tectonic domain. The main marine and geological factors controlling fluid escape include active faults, sediment overpressure, seismic activities, sea-level changes, tidal activities and seabed landslides. Fluids are sourced from different intervals (thermal, biogenesis, and natural gas hydrate decomposition) in different sea areas, and the migration of fluids is mostly through fault planes, mud volcanoes and gas chimneys to the seafloor. To summarize and establish the model and theory of seabed fluid escape, it is suggested that more attention should be paid to the investigation and detection of the development areas of the seabed fluid escape activities in the Tethys tectonic domain. Moreover, the further analysis of the mechanism of the fluid escape-related geomorphic features, as well as the marine and geological controls in the special oceanic regions will provide basic support for the subsequent research.