Offshore Transport and Sorting Particles picked up by wave motion move downslope, but the deeper the water, the less energy is involved in wave motion, so smaller and smaller particles are moved farther off shore. This results in size sorting of sediment, with grain size decreasing away from coast. Shaping of Coasts Coast represents the boundary between sea and land. When waves hit the coast, they can erode by breaking up rocks into finer particles and abrading other rocks by flinging rocks, sand and water against them. Over time, the effects can be large.
Sediment is moved and redeposited to increase the size of continental shelves.
The effects on the land surface can be seen by examining the shore profile. Beaches occur where sand is deposited along the shoreline. A beach can be divided into a foreshore zone, which is equivalent to the swash zone, and backshore zone, which is commonly separated from the foreshore by a distinct ridge, called a berm . Behind the backshore may be a zone of cliffs, marshes, or sand dunes. Rocky Coasts - Where wave action has not had time to lower the coastline to sea level, a rocky coast may occur.