Composition of Black Sediments at Rhossili

Composition of black beach sediments viewed under the microscope

Natural patterns on a sandy beachImages of patterns on the beach caused by wave action winnowing out lighter black sediments from the heavier yellow sand grains have been shown in earlier posts. Here are three microphotographs of the black sediments from a small sample that I scooped up on the shore at the time. Sorry there is no scale because I haven’t fathomed out how to include one in the images yet.

Natural patterns in black detritus on the strandline at Rhossili beachHopefully these shots are clear enough to show that the numerous black particles are small fragments of waterlogged wood; shiny hard pieces of coal (coal dust); a few large pale seeds not yet identified; minute fragmented seashells such as mussels; and many white slender organic objects which I think are small fish rib bones but could be or include heart urchin spines. It was these bones that gave the dried sample in the petri dish an almost fibrous appearance. I am going to see if I can find someone from the world of archaeology who would be familiar with the analysis of this type of material – to see if I can get some more specific information about these black sediments from the beach at Rhossili in Gower.

Composition of black beach sediments viewed under the microscope

Composition of black beach sediments viewed under the microscope

Patterned Sand RB April 2017b

Patterns on beach sand

Patterned Sand 8 – 14: Naturally formed patterns of black sediment on yellow sand were photographed on the beach at Rhossili Bay, Gower, in April 2017. The black sediments were mainly composed of minute pieces of rotten wood, coal dust, and miniscule fish bones, with a small proportion of seeds. The images have been digitally colour-enhanced to emphasise the patterns of this natural abstract art.

Patterns on beach sand

Patterns on beach sand

Patterns on beach sand

Patterns on beach sand

Patterns on beach sand

Patterns on beach sand

Rippled Water BH 2016b

Rippled Water 7 – 15: Natural patterns of shallow wind-rippled water in sandy pools near the tidal island of Burry Holms, Rhossili, Gower, in South Wales. The original photographs have been colour-modified to highlight the lines of reflected sunlight that trace the surface sculpturing of the water.

Patterned Sand RB 2017a

Patterns on beach sand

Patterned Sand 1-7 – Naturally formed patterns of black sediment on yellow sand were photographed on the beach at Rhossili Bay, Gower, in April 2017. The black sediments were mainly composed of minute pieces of rotten wood, coal dust, and miniscule fish bones, with a small proportion of seeds. The images have been digitally colour-enhanced to emphasise the patterns of this wonderful natural abstract art.

Patterns on beach sand

Patterns on beach sand

Patterns on beach sand

Patterns on beach sand

Patterns on beach sand

Patterns on beach sand

Rippled Water BH 2016a

Natural patterns in wind-rippled water

Natural patterns in wind-rippled water

Natural patterns in wind-rippled water

Natural patterns in wind-rippled water

Natural patterns in wind-rippled water

Natural patterns in wind-rippled water

Rippled Water 1-6 – Natural patterns of shallow wind-rippled water in sandy pools near the tidal island of Burry Holms, Rhossili, Gower, in South Wales. The original photograph has been colour-modified to highlight the lines of reflected sunlight tracing the surface sculpturing of the water.

Flints Embedded in Studland Chalk

Flint nodule embedded in chalk

Flint nodules embedded in the low cliff between two minor faults in Studland Chalk Formation exposures at South Beach on Studland Bay, Dorset, England.  At the top of the cliff face is a layer of ironstone and iron-stained flints that has caused the rusty stain on the chalk below. Elsewhere the rocks are covered with a fine coating of green algae.

A couple of useful references for the geology of the area in which these photographs of the chalk and flints were taken:

Barton, CM, Woods, MA, Bristow, CR, Newell, AJ, Weathead, RK, Evans, DJ, Kirby, GA, Warrington, G, Riding, JB, Freshney, EC, Highley, DE, Lott, GK, Forster, A, and Gibson, A. 2011. Geology of south Dorset and south-east Devon and its World Heritage Coast. Special Memoir of the British Geological Survey. Sheets 328, 341/342, 342/343, and parts of 326/340, 327, 329 and 339 (England and Wales), 9–100.

Cope, JCW, 2012 Geology of the Dorset Coast, Geologists’ Association Guide No. 22, Guide Series Editor SB Marriott, The Geologists’ Association, 191-194. A serious guide for the more dedicated amateur and professional.

Ensom, P and Turnbull, M 2011 Geology of the Jurassic Coast, The Isle of Purbeck, Weymouth to Studland, published for the Jurassic Coast Trust by Coastal Publishing, ISBN 978-1-907701-00-9, pages 96-117. A beautifully illustrated beginner’s guide to the geology of the area – one of a series of excellent publications by the Jurassic Coast Trust.

Swanage Solid and Drift Geology (map), British Geological Survey (Natural Environment Research Council) 1:50,000 Series, England and wales Sheets 342 (East) and part of 343

Flint nodule embedded in chalk

Low chalk cliff with row of embedded flints

Flint nodule embedded in chalk

Line of flint nodules embedded in chalk

Flint nodule embedded in chalk

Line of flint nodules embedded in chalk

Flint nodule embedded in chalk

Line of flint nodules embedded in chalk

Flint nodule embedded in chalk

Flint nodule embedded in chalk