abyssal plain
noun1
Geography, Natural sciences A large expanse of very flat and smooth ocean floor, usually found at depths of 4,600 to 5,500 meters (15,000 to 18,000 feet).
- Innocuous as it sounds, this note was a starting gun for a resource race on the planet’s last vast frontier: the abyssal plains that stretch between continental shelves deep below the oceans.2021 September 27, Jonathan Watts, “Race to the bottom: the disastrous, blindfolded rush to mine the deep sea”, in The Guardian: