Ocean trenches
Subduction
At the subduction zone of two tectonic plates.
The deepest parts of the ocean floor are caused by plate tectonic subduction and occur where the sea floor sinks back into the mantle in a subduction zone. These areas are called deep sea trenches and the Challenger Deep in the Mariana Trench in the Pacific is the deepest known point in Earth's oceans.
Rift valleys, sea-floor spreading and mid-ocean ridge.
in a subduction trench, because of Harry Hess' theory of sea floor spreading. Meaning that the rock is formed new at the mid-ocean ridge, and moved out towards the coasts into a subduction zone years and years later.
It is called subduction.
subduction is the answer.
i think that its subduction ...
Subduction of the ocean floor takes place at trenches.
Ocean Trenches
That is called subduction.
trench
subduction
Subduction .
your answer is subduction
deep-ocean trench
deep-ocean trench