The landscape of Scratchy Bottom, like much of this area, was formed by glacial melt water flowing to the sea. The high ground to the West is Swyre Head. The reef of Portland Stone off here was formed by complex folding that took place in this area around 30 million years ago, when the Continents of Africa and Europe collided forming the Alps.
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Durdle Door Beach in Winter
Coastal erosion in action from rough winter seas at Durdle Door Beach
Chalk, Upper Greensand, Gault, Wealden Beds, Purbeck Beds, Portland Stone
Shingle on Sand and Rock
Coastal Features: The Great Unconformity and The Cretaceous Blanket, Chalk Cliff Erosion, Chalk Beach
The beach beneath the sand at Scratchy Bottom comprises of chalk containing bands of flint. This is clear evidence that the cliffs here have been twisted upright by the complex folding that took place in this area around 30 million years ago, when the Continents of Africa and Europe collided forming the Alps.
The Great Unconformity and The Cretaceous Blanket
The sediments which make up the Jurassic Coastline were deposited in the following order, Triassic, Jurassic and Cretaceous, with the oldest rock, the Triassic sitting at the at the bottom of the pile.
Part way through the Early Cretaceous Period the sea levels dropped and the layers of rock were tilted to the East by earth movements. Overtime the exposed rocks were eroded before sea levels rose again, depositing more Cretaceous sediments.
The combined tilting and erosion explains why the Jurassic Period is completely missing in East Devon and why areas of cliff all along the coastline are capped with Cretaceous rocks which are millions of years younger than the sediments laying directly beneath them.
Chalk Cliff Erosion
Erosion of coastal Chalk cliffs is slow. Chalk is relatively hard, and only becomes unstable when the sea has carved a cave into its base, destabilising the weight of cliff above. The sea then has to wash away the cliff fall before the process can start all over again. The milky coloured seawater found at the base of Chalk cliffs, particularly around fresh falls, is evidence of coastal cliff erosion in progress.