Seaweed Strands with Crinkled Kelp

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.

Rock Pattern & Texture at Kimmeridge Again

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For information about the geology of this location please look at:

John C. W. Cope Geology of the Dorset Coast, Geologists’ Association Guide No. 22, Geologists’ Association, 2012, pp 159-167, ISBN978 0900717 61 1.

West, Ian. Kimmeridge Bay, Dorset. Geology of the Wessex Coast of Southern England. An on-line information resource.

M. A Woods (compiler) Geology of south Dorset and south-east Devon and its World Heritage Coast, British Geology Survey, NERC, 2011, pp 61 – 67, ISBN 978 085272654 9.

 

 

Rock Strata from Kimmeridge Cliffs – Part 2

Detail of cliff strata from Kimmeridge Bay

The second selection of photographs showing details of the rocks in the Upper Kimmeridgian Clay cliff mudstone and shale strata with iron staining on the east side cliffs of Kimmeridge Bay in Dorset, England on the World Heritage Jurassic Coast.

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Rock Strata from Kimmeridge Cliffs – Part 1

Detail of cliff strata from Kimmeridge Bay

The first selection of photographs taken at Kimmeridge Bay in Dorset, England, yesterday (27 March 2015) showing details of the natural patterns, textures, and colours of the rocks. The rocks are described as rhythmically inter-bedded blocky, organic-poor mudstone and fissile, organic rich shale.

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

Detail of cliff strata from Kimmeridge Bay

For information about the geology of this location look at:

John C. W. Cope Geology of the Dorset Coast, Geologists’ Association Guide No. 22, Geologists’ Association, 2012, pp 159-167, ISBN978 0900717 61 1.

M. A Woods (compiler) Geology of south Dorset and south-east Devon and its World Heritage Coast, British Geology Survey, NERC, 2011, pp 61 – 67, ISBN 978 085272654 9.

Patterns of cracks at Kimmeridge

 

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Natural patterns of cracks in the surface layers of a shale rock platform on the seashore at Kimmeridge Bay in Dorset, England.

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Kimmeridge Rocks 7-9

Cliff strata at Kimmeridge Bay

The wide bands of hard limestone exposed by the weathering cliffs at Kimmeridge Bay all have special names to distinguish them in their alternating sequence with the softer shales. The layers are inclined to the horizontal and their line can be traced gently sloping from one side of the bay to the other in the stacked strata of the cliff.

I believe this particular layer is called the Washing Ledge Dolostone Bed, which is part of the Aulacostephanus autissiordorensis Zone of the Lower Kimmeridge Clay from the Jurassic Period. It is a ferroan dolomite with a narrow, dark grey, central bituminous shale band (also called a central oil-shale parting). The limestone is stained yellow and red by the oxidation (rusting) of the iron minerals on the exposed surface of the rock. The colour contrasts dramatically with the grey shales around it.

Reference

West, Ian. Kimmeridge Bay, Dorset. Geology of the Wessex Coast of Southern England. An on-line information resource.

Cliff strata at Kimmeridge Bay

Cliff strata at Kimmeridge Bay

COPYRIGHT JESSICA WINDER 2013

All Rights Reserved

Kimmeridge Rocks 4-6

Cliff strata at Kimmeridge Bay

The cliffs at Kimmeridge Bay in Dorset, UK, are characterised by alternating hard and soft strata. Multiple thin layers of softer shale rock are sandwiched between wide bands of harder limestone. When the shales crumble and erode out, the heavy limestone becomes unsupported, often projecting as a jagged sill from the cliff face, and dangerously prone to falling onto the beach.

In each of these photographs a projecting ledge of limestone has broken away fairly recently, perhaps in the last decade. The vertical surface is more or less flush with that of the shales above and below it in the sequence. In the last picture, Kimmeridge Rocks 6, you can see that the shales below the hard band have started to erode back once more (indicated by the dark shadow on the right cast by the overhanging limestone).

Cliff strata at Kimmeridge Bay

Cliff strata at Kimmeridge Bay

COPYRIGHT JESSICA WINDER 2013

All Rights Reserved 

Kimmeridge Rocks 1-3

Wet rock colour and texture

Rock textures at Kimmeridge Bay on Dorset’s Jurassic Coast where water runs down the cliff face. Deep orange-red iron deposits on the surface of the grey limestone are revealed by recent rock falls; and granular calcium precipitation coats rock where water falls persistently.

Wet rock colour and texture

Wet rock colour and texture

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Natural pattern of seaweed on rock (5)

Weed2KimMar05aBlog5 Natural arrangement of Sea Oak seaweed dried onto limestone rock pavement, Kimmeridge, Dorset, UK, on the Jurassic Coast World Heritage Site (5) 

A frond of the brown seaweed Sea Oak, Halidrys siliquosa (Linnaeus) Lyngbye on limestone rock platform at Kimmeridge, Dorset, UK, on the Jurassic Coast.

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Natural arrangement of seaweed on rock (3)

P1090689fBlog3 A natural arrangement of brown seaweeds, with Egg- and Toothed Wrack, washed ashore onto the rocky strandline at Kimmeridge Bay, Dorset, UK on the Jurassic Coast World Heritage Site (3) 

A natural arrangement of mostly brown seaweeds, with Egg- and Toothed wrack, washed ashore on the rock platform at Kimmeridge Bay, Dorset, UK – part of the Jurassic Coast. Some of the seaweeds are drying out to give a drier, crisper texture with wonderful golden-yellow colours that contrast with the olive-brown leathery textures of the underlying layers of seaweed on the strandline.

COPYRIGHT JESSICA WINDER 2011

All rights reserved