Wave Erosion - energy is concentrated on headlands due to refraction (bending of waves)
& the energy is reduced in bays
Wave-cut Cliff - produced by wave action cutting away its base. The cliff develops as the
upper portions collapse after being undermined - may be evident in sea caves;
Continued erosion of sea caves produces sea arches & as they crumble stacks are created.
Rate of Wave Erosion
1) composition of coastal bedrock - igneous, metamorphic & hard sedimentary rocks are
relatively resistant while weak sedimentary (sandstone, shale) are easily eroded
2) degree of exposure
3) size of waves
4) tidal range - smaller the range, greater the erosion
Features of Depositional-Type Shores
Longshore Currents - a current located in the surf zone and running parallel to the shore
as a result of breaking waves.
Longshore Drift (large scale) & Littoral Drift (small scale) - movement of sediment by the
process just described
Numerous depositional features result from longshore drift & other processes
Spit - a linear ridge of sediment attached to the land at one end with the other end in the
direction of the longshore drift
Baymouth Bar (Bay Barrier) - ridge of sediment that cuts a bay off from the ocean; when
the longshore drift comes to an embayment, the waves lose some of their force as they
are refracted into the embayment & drop part of their sediment and a bar builds up
across the mouth of the bay.
Tombolo - a sand ridge that connects an island with another island or with the mainland.