Cainozoic, introduction, Wales
From: Howells, M F. 2007. British regional geology: Wales. Keyworth, Nottingham: British Geological Survey.
Towards the end of Cretaceous times, Europe began to be affected by compressional forces as the ocean (Tethys) that had separated Europe from Africa for most of Mesozoic times began to close and the Alpine orogeny was initiated. The culmination occurred in early Eocene to possibly Miocene times when the Alps and Carpathian mountain chains formed at the southern edge of the European craton. Broadly contemporaneous with these events was the opening of the north-east Atlantic with intense igneous activity in north-west Britain and, in the North Sea, extensive subsidence and sedimentation. However, within the craton, between these major tectonic expressions, the Alpine effects in Wales were mainly in the rejuvenation of basement structures and broad crustal warping.
At the end of the Cretaceous, an episode of mass extinction saw the demise of many marine faunas and, more famously, the dinosaurs. The cause has been attributed to a major meteorite impact followed by an intense and prolonged period of climatic change. However, there is little evidence of this catastrophic event in the geological column about Wales where, as in most basinal areas, sedimentation across the boundary was uninterrupted.
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