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Photos from Sandpoint, North Somerset

These are phtos from a visit I made in August 2006 to look at the volcanic features from the Carboniferous period and the Pleistocene raised beach, both mentioned in geological books on the area.

The first photo is of the Pleistocene raised beach. This rests on a wave-cut platform around 6m above the current high water of spring tides.The bouldery material, which is surrounded by abundant broken shells, is believed to be from the Ipswichian Interglacial (that's the interglacial before the last glacial) and the material directly on the wave-cut platform at the base from periglacial conditions in early Ipswichian, or late Wolstonian (not the last glacial, but the one before that) times.

The raised beach

Looking West along the point away from the raised beach. The cliffs are Black Rock Limestone of the Tournaisian Series of the Carboniferous.The mud to the right sits on a wave-cut platform at about mid-tide level. I vaguely remember reading that it's considered this platform, and others in the area, are too extensive to have been eroded in the relatively short space of time since sea levels started to rise at the end of the last glacial. Instead, the sea has just re-commenced a process started in a previous interglacial when sea levels were similar.

Looking west

Pillow lava. Again Carboniferous.

Pillow lava

Pillow lava, as above, can be seen in the foreground. Behind, are beds of volcanic tuff, with occasional thin beds of limestone. The cliff at the back is Black Rock Limestone. To the top left the raised beach can be seen against a vertical limestone cliff. For scale, the white boulder on the pillow lava is about 1.5m off the beach below. Although the apparent dip of the bedding is to the right, there is a larger component dipping down away from the point the picture was taken.

Various features

Volcanic tuff (volcanic airfall material) cut by a calcite vein.

Tuff

Lapilli -- coarser volcanic airfall material within the tuff.

Lapilli

Follow the wall to the right, and just beyond is the raised beach seen from a different angle. The grass in the foreground is about at the raised beach level, and the slope behind probably conceals the cliff face which would have been contemporary with the beach.

The top of the cliff

An active geomorphological feature -- terracettes. Caused by soil creep, and probably enhanced by sheep walking along them.

Terracettes

2006