Abstract:

Study on the sedimentary architecture and evolution of deep-water channel is one of the most interesting fields in sedimentology. Based on high-resolution threedimensional seismic data sets which cover 470 km², the sedimentary architecture and evolution of submarine channels are discussed in deep-water Rio Muni basin. Four conclusions can be drawn in this paper: (1) The sinuosity of submarine channels are main dominated by the sediment supply and the seafloor gradient. Two main types of submarine channels: straight channels and sinuous channels have been recognized in the study area. (2) The high sinuosity submarine channel indents the shelf margin and is linked to areas of high coarse-grained sediment supply. Their mophologies often show asymmetrical cross-sections, terraces, slumped edges, lateral migration and abandoned channel. (3) The submarine channels heading on middle or upper continental slopes have a low sinuosity. Straight channels- morphologies commonly include a U-shaped cross-section, smooth walls lacking slumps or terraces, aggradational evolution. The straight channels with low sediment supply were draped by hemipelagic deposition. (4)The sinuosity of a submarine increases as the shelf gradient decreases.

Key words: sinuous channel, straight channel, sedimentary architecture, Rio Muni basin