It is called a terrane (more specifically, a tectonostratigraphic terrane). An example of these sutured chunks of oceanic plate is found in south central South Carolina.
subduction is the answer.
It is called subduction.
Subduction.
Subduction.
i think that its subduction ...
That is called subduction.
Ocean trenches
Subduction of the ocean floor takes place at trenches.
subduction
A trench.
Subduction .
This is known as subduction.