1. Katedra Geomorfologii, Uniwersytet ?la?ski, B?dzińska 60,41‐200 Sosnowiec, Poland peter.thomas.walsh@gmail.com;2. Laboratoire de Géomorphologie et Gestion des Millieux Naturels, Université des Sciences et Technologies de Lille, 59655 Villeneuve d'Ascq Cedex, France yvonne.battiau@orange.fr;3. Sea Hollies, Chapel Lane, Freshwater East, Pembroke, SA71 5LB, UK sid.howells@virgin.net;4. School of Earth and Geographical Sciences, The University of Western Australia, Nedlands, WA 6009, Australia cliffol@cyllene.uwa.edu.au;5. Institute of Geography and Earth Sciences, Aberystwyth University, Ceredigion, SY23 3DB, UK mathew.rowberry@wits.ac.za
Abstract:
The thickest development of Carboniferous Limestone in Great Britain (about 1200 m) is in the Pembroke Peninsula of SW Wales. In various places, the regularity of the normally well‐stratified limestone is broken by zones of disturbance, which are spectacularly displayed in magnificent near‐vertical cliff sections. The zones generally occupy the whole of the 50 m‐high cliffs and are up to 300 m wide. The chief component of these zones is a chaotic, clast‐supported breccia, composed of angular limestone fragments welded together with varying degrees of firmness by sparry calcite veining or a normally sparse, red‐pink sandy or silty matrix. The breccias are very easy to distinguish and form a striking contrast to the grey cliff scenery hereabouts ( Figs 1, 2 ), yet they have not been discussed much—until now. Figure 1 Open in figure viewer PowerPoint Location map, showing localities mentioned in the text, the outcrop of the Carboniferous Limestone, the chief synclinal axes and the distribution envelope of the Gash Breccias (after Thomas 1971 ). 1. Flimston Bay; 2. Bullslaughter Bay (west); 3. Bullslaughter bay (east); 4. Trevallen; 5. Box Bay; 6. Draught; 7. Whitesheet Rock; 8. Lydstep Point; 9. St Margaret's Point; 10. Den Point; 11. Valleyfield Top; 12. Pembroke Castle.
