Category:18. Wales (Cymru)
This account provides a broad perspective of the geology of Wales, which comprises a diverse landscape that includes the mountains of Snowdonia and the Brecon Beacons, the upland plateau of Central Wales and the flatter landscapes of the valleys and coastal areas, including the Gwent Levels south of Newport, Vale of Glamorgan and island of Anglesey. Figure P902274 provides a geological sketch map of this region showing the rock types occurring in relation to the major towns and cities. This account outlines the geology to a depth of at least a kilometre and summarises the current and historical use of the geological resources in the area.
The geology near the surface is well known from abundant natural outcrops of rock, such as coastal cliffs and mountain crags, as well as quarries and mines. However, there are few deep boreholes in Wales so that, at greater depths, the understanding of the geology is largely conceptual, based on projection of surface measurements and observations to depth. Exceptions to this are the former coal-mining areas of North and South Wales, where a number of deep shafts and boreholes have provided insights into the deep structure. Geophysical seismic surveys have provided some information on the rocks by sending sound waves through the ground but they are very limited and only cover parts of the South Wales Coalfield and Vale of Glamorgan.