This is a gallery of some of the rock textures and patterns found in material brought down to the seashore by land-slips on the eastern half of Ringstead Bay in Dorset, England. Some might say that the geology of this half of the bay is much more complex and interesting than the western half. In addition to a natural progression of strata from older rocks in the west to younger rocks in the east, there are faults and land-slips that result in much of this variable material appearing in mudslides at the top of the shore, and as boulders on the beach.
The pictures show details of the textures and patterns in some of the rocks and sediments that were laid down after the Ringstead Formation rocks that were illustrated in earlier posts. These later strata include those from the Jurassic Period Kimmeridge Formation (shales and clays), Portland Limestone Formation (Portland Freestone, Portland Cherty Series, Portland Sand), and the basal part of the Purbeck Formation. The layers can be seen in exposures west of Holywell House on top of the ‘cliff’; and boulders from them often end up rolling down to the beach below.
A bit further east the geologically more recent Cretaceous Period strata are exposed. These include the Gault, Greensand, and Lower, Middle, and Upper Chalk. All of these rock exposures are subject the slippage and land slide so that boulders frequently end up on the beach. I haven’t yet reached a complete understanding of the geology in this location. I have attached a description to each image that you can see if you click to enlarge the pictures. However, I cannot say with absolute certainty the identity of each of the rocks I photographed – but I am working on it with the help of the references listed below; and I’m hoping to visit the Dorset County Museum to look at their rock collections soon.
West, I.M. 2013. Ringstead Bay to White Nothe: Geology of the Wessex Coast (Jurassic Coast, Dorset and East Devon World Heritage Site). Internet field guide. By Dr. Ian West, Romsey, Hampshire and Visiting Scientist at Southampton University. http://www.southampton.ac.uk/~imw/Ringstead-White-Nothe.htm. Version: 19th December 2013
British Geological Survey (2011) Geology of south Dorset and south-east Devon and its World Heritage Coast, Compiled by M. A. Woods, Special Memoir for 1:50 000 geological sheets 328 Dorchester, 341/342 West Fleet and Weymouth and 342/343 Swanage etc, NERC, ISBN 978 85272 654 9.
Melville, R. V. and Freshney, E. C. (1982) British Regional Geology: The Hampshire Basin and adjoining areas, 4th edition, Institute of Geological Sciences, NERC, HMSO, ISBN 0 11 884203 X.
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