 Abyssal fan

Abyssal fans, also known as deep-sea fans, underwater deltas, and submarine fans, are underwater geological structures associated with large-scale sediment deposition and formed by turbidity currents.They can be thought of as an underwater version of alluvial fans and can vary dramatically in size, with widths from several kilometres to several thousands of kilometres The largest is the Bengal Fan, followed by the Indus Fan, but major fans are also found at the outlet of the Amazon, Congo, Mississippi and elsewhere.