SURFICIAL FEATURES AND DISTRIBUTION PATTERNS OF THE COLD SEEP SYSTEM ON FORMOSA RIDGE

The Formosa Ridge cold seep system is one of the most active cold seep sites located at the passive continental margin of the South China Sea. Based on the bathymetric data and video data collected by the multibeam echo sounder system and high-definition cameras mounted on the Remotely Operated Vehicle, the seabed topographic features of the cold seep site and the surficial features of the cold seep system were described. The main surficial features of the cold seep system include authigenic carbonate crusts, chemosynthetic communities, and gas plumes. The development of carbonate structures with various morphological features caused the anomalous seabed topographic features of the cold seep site. The distribution of the chemosynthetic communities was controlled by the positions of seabed fluids venting or emission through the seabed, which correlate well with the fissures or fractures developed within the authigenic carbonate crust. However, not all fissures and fractures could serve as favorable conduits for the migration of seabed fluids. To some degree, the surficial features of the cold seep system could effectively influence the migration conduits of the seabed fluid flows.