What is an abysmal plain?

An abysmal plain refers to a large, flat area of the deep ocean basin. These plains are located at depths of around 3,000 to 6,000 meters (approximately 10,000 to 20,000 feet) below sea level, making them some of the most expansive and least explored ecosystems on Earth. They cover significant portions of the ocean floor, characterized by their relatively uniform topography and fine sediments that accumulate slowly over time.

The formation of abysmal plains often results from the deposition of sediments carried by ocean currents, which settle on the ocean floor, creating a smooth, flat surface. This distinctive feature contrasts sharply with other underwater geographical structures such as mountains, trenches, or volcanic islands, each of which has its distinct characteristics and formation processes that do not align with the flat, expansive nature of an abysmal plain.