An
abyssal plain is an underwater
plain on the deep
ocean floor, usually found at depths between 3000 and 6000 m. Lying generally between the foot of a
continental rise and a
mid-ocean ridge, abyssal plains cover more than 50% of the
Earth’s surface. They are among the flattest, smoothest and least explored regions on Earth. Abyssal plains are key geologic elements of
oceanic basins (the other elements being an elevated mid-ocean ridge and flanking
abyssal hills). In addition to these elements,
active oceanic basins (those that are associated with a moving
plate tectonic boundary) also typically include an
oceanic trench and a
subduction zone.