The amazing thing about the weathered timbers in the old breakwater constructions at Church Cliff in Lyme Regis was the woodgrain. Sinuous curves of ridges and grooves in the water-etched wood seemed to mimic the waves themselves, sometimes gentle, and sometimes with crashing surf. Tiny pale barnacles living in the grooves resembled sunny day sparkle spots on the waves, and were keeping company with small marine snails and black lichen taking advantage of the relative security offered by the wooden hollows.
I noted an interesting phenomenon at Weymouth in Dorset recently. The rusty iron panels of the pier structure exhibited tide-marks or tide-lines of dried sea foam from a previous high water. I have never seen that before. The contrasting colours, patterns, and textures of the creamy lines against the multi-coloured oxidising metal made interesting compositions.
Wikipedia says about sea foam:
Sea foam, ocean foam, beach foam, or spume is a type of foam created by the agitation of seawater, particularly when it contains higher concentrations of dissolved organic matter (including proteins, lignins, and lipids) derived from sources such as the offshore breakdown of algal blooms. These compounds can act as surfactants or foaming agents. As the seawater is churned by breaking waves in the surf zone adjacent to the shore, the presence of these surfactants under these turbulent conditions traps air, forming persistent bubbles that stick to each other through surface tension. Due to its low density and persistence, foam can be blown by strong on-shore winds from the beachface inland.
Thick mats of seaweed wash ashore on beaches along the Jurassic Coast. Dead seaweed is often automatically viewed as horrid, unsightly, and a nuisance – but if you pause and look, there is beauty in it. There are many types of seaweed to be discovered in the masses on this strandline. Their fronds intertwine in a kind of accidental natural weaving. Each species has its own characteristic shape, texture, and pattern. Their combined presence forms greater abstract designs of infinite variety, the individual fronds making strands or threads as in a tapestry. The puckered patterns of the crinkly Sugar Kelp stand out as the most decorative features of the assemblage. The colours change from deep olive brown to golden yellow and cream as the algae decompose. The textures range from leathery to satiny, from slimy to crispy depending on moisture content. Opaque and hardening on exposure to air; or translucent and soft when floating in shallow water rock pools.
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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