Subduction is one of such processes that causes thick sequences of sedimentary layers to accumulate along the boundaries of continental and oceanic plates.
Continental and oceanic plates meets at a subduction zone which is a convergent margin.
At this zone, the dense oceanic plate subducts or dives into the weak and less dense asthenosphere below.
As it subducts, the ocean floor sediments on top is peeled off and the slab of lithosphere pulls down.
This causes an accretionary wedge between the two zones.
Most the sediments will eventually get metamorphosed into a metamorophic rock.
