ABSTRACT
The work of the sea is focused at the coastline, probably the most active and diverse of Earth's geomorphological features, found in every tectonic and climatic setting. The coastline is the outermost limit of permanent land, which separates the broader coastal hinterland from shore and marine environments. Wave form is the outcome of offshore features of approaching waves, modified by water depth in the inshore zone, coastline geometry and wind-induced wave direction. Tidal ebb and flow stimulate tidal currents with substantial fluxes of water, energy and sediment around the coastline. Deltas extend the coastline most obviously where tide and wave energy are low, in protected shelf seas, and do little to reshape the delta. In a general sense, any natural or human action on the coastline is likely to alter, or realign, the precise 3-D position of the land-sea boundary.
