Pebbles, shells, and a feather on the beach near Whiteford Point

A sand bar spreads southeast from Whiteford Point in Gower, South Wales. At low tide in the Burry Estuary, it is part of a very extensive sandy area over which cockle and mussel fisherman can traverse in vehicles from places further along the north Gower coast. The sand depth is variable and mostly envelops a spit of pebbles. Sometimes the pebbles are entirely hidden. Sometimes they are partially exposed. Intermixed with the pebbles are seashells – cockles, mussels, whelks, and oysters are the most commonly occurring. There is a wide range of colours and textures in the pebbles and they are particularly interesting because of the range of rock types they represent.

As you take a 360 degree scan of the horizon from this isolated expanse of sand and pebbles, there is not a single rocky outcrop in sight. So where have these beach stones come from? The collection includes sedimentary rocks from the locally occurring Carboniferous limestone and Devonian sandstones, mudstones, and conglomerates – like the bedrock exposed at Rhossili and at Broughton Bay. It also includes samples from higher up in the Carboniferous strata such as the Millstone Grits, sandstones, and shales, and Coal Measure layers. These strata underlie the Burry Estuary into which this spit extends, east Gower, and the Swansea district and way beyond. There are many rock types with which I am not familiar but I notice that some are metamorphic and igneous in nature. So how have all these rocks ended up on this spit, far from their place of origin?

Part of the answer is undoubtedly the effect of sea drift, currents, and storms carrying weathered and broken stones along the shores of Carmarthen Bay and into the estuary or inlet – but a significant proportion of the stones are thought to have been brought to the area from considerable distances away by glaciation, and deposited by the melting of an ice sheet, possibly in the late Devensian era about 24,000 years ago. Most of these stones lie hidden in a mass beneath the Whiteford Dunes but some are exposed high on the shore at the foot of the dunes, and beneath the disused iron lighthouse on Whiteford Point. Over time the waves have dislodged the often frost-shattered stones from the surface of the deposit, and washed them further along the beach around the Point to form pebble spits and banks, in the process smoothing and rounding them into the pebbles visible today.

Click here for more posts about Whiteford Sands, Whiteford Point, and Whiteford Burrows.

11 Replies to “Pebbles at Whiteford (4)”

  1. What a sea of pebbles and shells! My kind of place, to just sit down anywhere and have a look! There would be one or two missing by the time I’d finished!

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  2. Really? It must be a rather child-like way of being – children (and scientists!) are always curious about the world around them and asking odd questions.

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  3. This sandy-pebbly spit at Whiteford in Gower is one of my favourite places and I love it best when I have it all to myself. It is like being on a beautiful remote island – full of curiosities if you know where to look or have the eyes to see. It is just a few steps away from the Wales Coastal Path which is increasingly popular; and near to Whiteford Burrows which was highlighted in The Times newspaper only this bank holiday weekend as one of twenty best British coastal walks on beaches, cliffs and dunes. Sometimes, nowadays, I find the footprints of other visitors!

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  4. Great photos of the pebbles at Whitford.
    I am interested in the types and origins of the pebbles and especially the possibility of the presence of metamorphic rocks.
    I would have thought that their origin is rather difficult to explain, even if transported as the result of glaciation. If they are recorded in the academic literature, perhaps you could let me have the reference.
    I will certainly revisit the lovely as soon as I can get back to a safer UK.

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  5. Hello, Robert. Sorry for the delay in replying. Although I have read about these long-distance travels of some beach stones and pebbles on Gower beaches, in general accounts of the geology of the area, it is surprisingly difficult to access the original literature on which the comments are based. I have done a Google search for publications and come up with a few possibly useful sources, but I am personally only able to get hold of the article abstracts. The full paper is often only available for a fee or if you have some sort of academic institutional access to websites. That said, there is a paper (for example) ‘Late Pleistocene deposits at Broughton Bay, Gower, South Wales: evidence for deposition at a non-marine Devensian ice margin’ by Campbell and Shakesby on Science Direct [https://www.sciencedirect.com/science/article/abs/pii/S0016787808801174] in which the authors state in the abstract “Facies variations within in situ till were caused by vertical transfer of materials within the basal ice layer, as marine and estuarine sediments were entrained from the floor of Carmarthen Bay by southward-moving ice. These basal sediments, together with more far-travelled, englacially-transported material, were deposited contemporaneously on west Gower, at or near the maximum limit of the Late Devensian Welsh ice sheet.” I can send more similar references later.

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  6. Hi Jessica. Many thanks for your long response to my question about the presence of metamorphic erratics at Whitford, which I believe is difficult to explain looking at geology of Wales and the route of glaciers during the Pleistocene.
    I will try to dig out the reference you mention.
    With regard to some of the pebbles that you highlight as metamorphic rocks it would be useful to look at these in more detail, I would very tentatively suggest that, at least, some are in fact Carboniferous, fluvial, sandstones and gravels, with irregular black carbonaceous laminae.
    I look forward to returning to UK, from the otherside of the world and once more stretching my legs on my beautiful Gower.

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  7. Yes, only a couple of stones looked to my eye a bit like schist. They certainly looked different from all the others, and I had recently been to Guernsey and looking at very old rocks something like it. It will be great when we can all travel again, and Gower is definitely going to be the first port of call, although I do not think that I will be able to walk so far as Whiteford Point any more.

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