Topic: Rivers & Coasts
Case Study: Coastal Area Case Study & Landforms
Location: The Dorset Coast, Southern England
Geographical Keywords • Marine erosion (Abrasion,
Hydraulic Action, Attrition, Solution)
• Weathering (Salt crystal growth, wetting/drying)
•
Mass Movement • Geology
•
Lithology
• Stack
• Arch
• Cove
•
Tombolo
• Transportation
•
Longshore drift
•
Deposition Case Study Detail Background The Dorset Coast has a number of very distinctive coastal features which from either erosion, transport and deposition of material along the coastline. The changing geology of the coast means that different features are found where the rock types change.
Arches and Stacks Near Studland Bay a more resistant outcrop of chalk rock is found which creates a headland. Here you can find
Old Harry Rocks; a collection of arches and stacks. The stacks begin as a crack or weakness in the rock which is eroded and weathered.
Overtime, the crack enlarges to form a cave and then an arch when it cuts through the headland. Eventually the roof of the arch collapses to leave a stack which can be further worn down to leave a stump and finally a wave- cut platform.
Cove Lulworth cove has been created because of hard and soft rock. Running parallel with the sea is a band of resistant limestone with softer sands and clays behind it. At Lulworth cove, erosion of a weakness in the limestone has cut through to the clays/sands . This has created a large cove as this rock is much more easily erodible.
Tombolo Moving West along the coast you find one of the longest stretched of beach in the country.
Chesil Beach is 18 miles long and has been created by the movement of sediment by longshore drift (know how this works. Longshore drift moves the material in an easterly direction towards Portland leaving lagoons behind some sections of beach. Overtime the beach has grown into a spit which has reached the Isle of Portland and formed a tombolo. Exam tip Learn how ab spitb forms too. Good examples (not in Dorset) include Spurn Head in Yorkshire and the Humber, and Hurst Castle Spit in Hampshire.
