A trench.
Trench
Subduction of the ocean floor takes place at trenches.
The prominent sea floor feature found in the central Atlantic ocean is called the Mid Atlantic Ridge.
Trenches are deep ocean features of subduction zones.
your answer is subduction
deep-ocean trench
deep-ocean trench
trenches
subduction is the answer.
Subduction
subduction
The ocean is 4 billion yars old, however due to subduction, the oldest sediment found in the ocean's floor is 180 million years old.