Submarine Fan (IMAGE) University of Washington Caption Just past the continental shelf in the Gulf of Mexico – the shelf is marked with the blue line – a fan of sediment has formed on the seafloor made up of silt and debris that settles out of Mississippi River waters flowing into the gulf. These alluvial, or submarine, fans are found wherever rivers run into the ocean. Crop residues sunk in such fans would become covered with silt, further ensuring that carbon would be locked away for long periods. Credit S. Strand/UW/U.S. Geological Survey Usage Restrictions Image credit required License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.