Pembrokeshire Geology

Apr 15 22:29

by Hypocentre

As most of the geoblogosphere has been posting images from their spring field excursions I suppose I'd better post some of mine. Each year I run a field course to Pembrokeshire. I've done now for 13 of the last 14 years and I still don't get tired of doing it (although I do get tired doing it). The geology is superb with classic exposures, evidence of (at least) four orogenies and a really good story to tell.

This is the classic Lady Cave anticline near Saundersfoot showing the northward verging folding of the Variscan.

This is a peperite, on Pen Anglas, near Goodwick. Peperites are where magma intrudes into wet, sloppy sediment and effectively here there is a liquid-liquid contact rather than a liquid-solid one. For more on peperites see Chris Rowan's recent blog post.

The 'Three Chimneys' at Marloes Sands features in several publications on the Silurian. Here the Llandovery sediments of the Skomer Volcanic Group are almost vertical. Despite the cleavage being shallower than the bedding the rocks are the right way up (just).