What are abyssal plains in the Atlantic Ocean?

Abyssal plains are vast, remarkably flat areas of the seafloor located at depths between 3,000 and 6,000 meters (10,000 to 20,000 feet). In the Atlantic Ocean, these features are particularly common and extensive, forming the upper surfaces of thick sediment deposits that fill broad depressions in the ocean floor.12

These plains are created by the accumulation of land-derived sediment, which smooths out preexisting irregular or mountainous topography. This process is driven by turbidity currents—dense, sediment-laden slurries that flow down continental slopes and deposit material into the deep basins. Between these events, fine-grained clay and the remains of microscopic organisms settle slowly through the water column.1

While the Atlantic floor is dominated by the Mid-Atlantic Ridge, the basins to the east and west contain both rugged abyssal hills and these extremely smooth abyssal plains. The Sohm Plain in the North Atlantic, for example, covers approximately 900,000 square kilometers.21