i think that its subduction ...
subduction
Subduction .
subduction is the answer.
subduction
The first process is called sea-floor spreading (rifting when it happens on land) and the second process is called subduction. Both processes are part of plate tectonics.
New rock is added to the ocean floor through a process called seafloor spreading, where magma rises from the Earth's mantle at mid-ocean ridges, cools and solidifies to form new oceanic crust. This process helps expand the ocean floor and contributes to the movement of tectonic plates.
The process in which the ocean floor sinks into the mantle is called subduction. This occurs at convergent plate boundaries, where one tectonic plate slides beneath another. Subduction zones are associated with deep-sea trenches and volcanic activity.
A long narrow and very deep canyon where the ocean floor bends down toward the mantle is called an ocean trench. This is caused by two plates pulling apart.
Why do scientists look to the ocean floor to research the mantle? Because magma from the mantle flows out of active volcanoes on the ocean floor. These underwater volcanoes have given scientists many clues about the composition of the mantle.
A long narrow and very deep canyon where the ocean floor bends down toward the mantle is called an ocean trench. This is caused by two plates pulling apart.
A long narrow and very deep canyon where the ocean floor bends down toward the mantle is called an ocean trench. This is caused by two plates pulling apart.
In a process taking tens of millions of years, part of the ocean floor sinks back into the mantle at deep ocean trenches.