Query: History of the pebbles
Query
I was recently laughed at by friends by suggesting the pebbles had been brought along the coast intentionally and built up (like at Seaford) to ward off sea damage to the coastline developments. If they’re natural, I also don’t understand why they stop at the tideline? I’d really appreciate it if anyone can explain either the history, or if natural, how such a significant difference can be seen in photographs over just 80 years?
Quietly Curious, 01-08-2003
Response
The pebbles on the south coast are the remnant of the chalk debris (which includes flints) which was eroded from the chalk landscapes of southern Britain by snow meltwater flows at various times in the past two million years. The last time this occured was about 10,000 years ago.
The chalk was deeply frozen and in the short summer defrosts the surface layer of snow and partly defrosted chalk would slump under gravity to lower levels. As the glaciers went into retreat from the English Midlands, and as more snow water was released, rivers, and then sea level rose. The Channel formed (as we know it) about 9,000 – 8,000 years ago and Britain was separated from European mainland. Marine activity swirled away the chalky muds of the channel area and left the flint debris behind.
Currents and wave activity gradually rounded the flints into sub-angular pebbles. Currents and storm conditions drove some of this ashore as a fringe to wave activity, leaving a large quantity in the deep channel. It is this deposit that is being pumped up for ‘marine aggregate’ (concrete.roads etc) and is pumped ashore for coastal defence measures as at Seaford.
The pebbles are separate from the shore platform that underlies them and the highly mobile shingle is moved in a largely easterly direction for 20/24 hours of the day. It does not move either side of high water. It all ends up at Dungeness eventually.
There is a worrying finding by Sussex University geographers which has become apparent recently, and that is the fact that the shingle is a decreasing resource and that rising sea levels on the south coast, linked to increased storm activity, and dwindling shingle, means a bleak time ahead for coastal dwellers.
Geoffrey Mead, sent to website mailing-list, 05-08-03
Comments about this page
At last! I have always thought that the pebbles were the result of erosion caused my nature, even as a boy. Some people think that they were put there by man but can you just imagine the man power and machinery needed for such a task! Even now you can see the pebbles embedded in the cliff face and from time to time there is collapse of the cliff face. It is patently obvious.
The beaches on the French side are the same. Must be natural.
The original question suggests ‘a significant difference … in photographs over just 80 years’. This photograph (from a web search) has very similar looking shingles from over 100 years ago:
http://www.oldukphotos.com/graphics/England%20Photos/Sussex,%20Brighton%20Beach%20and%20Pier%20circa%201890%27s.jpg
I wrote the long ‘shingle’ pieces [unbelievably!] 16 years ago. I am not sure what the question is from the last entry. The flint shingle is from the same sources and has had the same marine erosion processes then as now…and for the last 10,000 years! I am rather mystified by the image of a Victorian seaside that comes with the article above, which I have never seen before and am sceptical that it is actually Brighton. Any responses gladly received.
Hi Geoffrey, it doesn’t look like any of Brighton’s Piers …
A beautiful photograph on that link. I’m glad to have seen it : but of Hastings Pier, I think, with the pier of St. Leonards in the far distance.
Looks like Hastings. Lovely picture, though.
The image is Hastings Pier!
A reply to the reply of Mr Meads ! Thank you for your very clear and thoroughly informative reply, that has educated me.
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