Discuss the role of depostional processes in the production of coastal landforms
Case study: Ro wen spit
Ro wen spit is an example of a coastal landform which was formed by depostional processes. It is a composite spit which is made up of sand and shingle and lays south of Barmouths Harbour in Wales. It is a long and narrow stretch of land which was created by the sea and wind depositing sediment such as sand and shingle onto the land, creating the spit. Depending on the speed and energy of the wind(which is determined by the stretch) constructive and destructive waves are formed. At Ro wen spit, the fetch is fairly long meaning that the waves have time to build their energy up, creating constructive waves. The swash is strong so carries lots of sediment and the backwash is weak meaning that the energy is lost. Sediment is then deposited onto the beach, building and shaping it.
At Ro wen spit, there are two main sources of sediment. The first cominf from longshore drift as a result of thr South-West prevailing winds resulting in the net longshore drfit being towards the North. The sediment then builds up at Mawddach estuary where the coastline changes direction. (insert diagram below).
The secord source of sediment comes from pebbles brought by the sea level rise. In the last ice age sediment was brought down from the mountains as the glaciers melted and was deposited, moving the coastline to further out from its present position. As the glaciers melted, sea levels rose which resulted in cliff erosion and larger pebbles being trasnported by the roll over process to their present position today.
One of the landforms at Ro wen spit which was created by deposition is the curved end of the spit. The secondary winds encourage sand and shingle to curve around, along with the strong current which helps to stop the spit joining the mainland. The…