Abstract The collision of Siberia and the Kazakstan microplate with the eastern side of the Fennoscandia continent in the Permian amalgamated the last major continental fragments to produce the supercontinent Pangaea, which persisted into the Jurassic ( Fig. 13.1 ). During the last phases of this collision, during the latest Permian–Early Triassic, extrusion of massive amounts of flood basalts occurred in Siberia, to the east of the Urals ( Otto & Bailey 1995 ). Some have proposed this event as one of the key processes controlling the largest extinction in Earth’s history at the Permian–Triassic boundary ( Wignall 2001 a ; Benton & Twitchett 2003 ). During the Triassic, England and Wales lay beyond the western termination of the Tethys Ocean, which was divided into a northern part, the Palaeotethys, and a southern part, the Neotethys ( Fig. 13.1 ). Between these oceans occurred the Cimmerian terrains; several now widely separated continental fragments which had rifted from the northern fringe of Gondwana in the Permian ( Stampfli & Borel 2002 ). The Triassic witnessed the northward drift of these Cimmerian terrains, and the northward subduction of the Palaeotethys, which was mostly completed by the Late Triassic.

Abstract This paper presents a new interpretation of well-known outcrops on the south coast of the Bristol Channel at Watchet in southern England. It is prompted by our recent experience of high-quality three-dimensional seismic datasets from areas such as the Gulf of Mexico and Brazil which are dominated by salt tectonics. Previous structural interpretations of the Watchet outcrops were explained in terms of extension, inversion and strike-slip tectonics. We suggest that some of the structures in the area are not easily explained by any of these mechanisms, but that they are collapse structures associated with salt withdrawal and imply salt diapirism during the Late Triassic and Early Jurassic.