Please enable JavaScript.
Coggle requires JavaScript to display documents.
1.1 Coastal Landscapes (Sediment cells (A sediment cell is a stretch of…
1.1 Coastal Landscapes
-
Sediment cells
A sediment cell is a stretch of coastline and it's associated nearshore area within which the movement of coarse sediment, sand and shingle is largely self-contained.
-
There are 11 large sediment cells off the coast of England. The boundaries of a sediment cells are determined by the topography (the arrangement of the natural and artificial physical features of an area.) and shape of the coastline
-
Breaking waves
-
After a wave break, water moves up the beach as swash, driven by the energy from the breaking of the wave. The speed of this will decrease as it moves up the beach due to friction and the uphill gradient. When it has no more energy, it moves back down the beach as backwash. The energy from this movement comes from gravity and occurs perpendicular to the coastline, down the steepest slope angle.
Geology
Lithology
This describes the chemical and physical composition of rocks. Some rocks like clay have weak lithology, with little resistance to erosion, weathering and mass movement
Structure
This concerns the properties if individual rock types. (joints, cracks, bedding planes, permeability)
Structure influences the platform of regional coasts. Rock outcrops that are uniform or run parallel to the coastline are concordant coastlines.
Where rocks lie at right angles to the coast, they are discordant coastlines, which form headlands and bays.
Currents
-
Rip currents transport coastal sediment. They are caused by tidal motion or by waves breaking at right angles to the shore.
Ocean currents are generated by the Earth's rotation , convection and are set in motion by the movement of winds across the water surface. Warm ocean currents transfer heat energy from low latitudes towards the poles. Cold ocean currents transfer water from the poles towards the Equator. These are driven by offshore winds as have less of an effect on coastal landscapes.
Offshore
Constructive waves bring sediment to the shore from offshore locations and deposit it (marine deposition). Currents and tides do the same.
Wind also blows sediment from other locations. This is generally fine sand as wind has less energy than water.