Pebbles at Whiteford (4)

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.

“Blood” oozing from beach at Whiteford

It looked like blood but of course it wasn’t! Red liquid seemed to be oozing from the sand high on the shore towards the north end of Whiteford Sands on the Gower Peninsula in South Wales, approaching Whiteford Point. I have seen the phenomenon before and wrote about a possible explanation in  the post “Rusty pebbles at Whiteford”. Only on that occasion the seepage was more orange in colour and clearly ferruginous in nature. Yesterday, the liquid seemed much more concentrated and red, like blood, quite spectacular, but perhaps just a trick of the light. These photographs are as taken and not edited in any way as I am uploading them direct from my i-pad. I believe that the iron responsible for colouring the water draining down the shore is derived from an iron pan caused by decomposition of an ancient peat bed beneath the sand. It is possible to see the layers of peat and clay where they are exposed just below the seepage rivulets. The peat and clay layers are increasingly interesting as more logs and stumps of preserved trees and bushes are weathering out. More about these features in later posts.

Oyster Shells at Whiteford (25.07.13)

Oyster shell (Ostrea edulis Linnaeus) on the beach at Whiteford Sands

Click on the pictures to enlarge them and view the descriptions.

Oyster shell (Ostrea edulis Linnaeus) on the beach at Whiteford Sands

Oyster shell (Ostrea edulis Linnaeus) on the beach at Whiteford Sands

Oyster shell (Ostrea edulis Linnaeus) on the beach at Whiteford Sands

Oyster shell (Ostrea edulis Linnaeus) on the beach at Whiteford Sands

Oyster shell (Ostrea edulis Linnaeus) on the beach at Whiteford Sands

Oyster shell (Ostrea edulis Linnaeus) on the beach at Whiteford Sands

Oyster shell (Ostrea edulis Linnaeus) on the beach at Whiteford Sands

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