Appendices
The Variscan Orogeny is a mountain forming event which cause faulting and folding through the British Isles, which has then intern reactivated faults and caused synforms and antiforms to be created. This report talks about the structure, success and geological history and impact that this event has had on the British Isles mainly focusing on the Variscan front which ran through West Wales and the Bristol District. Also with some reference to post-Variscan activity.
Introduction
The Variscan orogeny occurred during the late Carboniferous to early Permian (290Ma) and is a mountain forming event. The mountains ranges which were formed are the mountains in Portugal and western Spain and south west Ireland and none formed in the UK. The variscan orogeny had effected Devon, Cornwall, Pembrokeshire, Vale of Glamorgan, Bristol…show more content… Geological History
The geological history in this area is that Silurian rocks were lain and deformed by the Caladonian orogeny and then Old Red Sandstone was lane down followed by the Carboniferous Limestone. This was then folded and faulted by the Variscan Orogeny, causing the antiforms and synforms in the area and the east to west trend of the fold axis. During the Varsican Orogeny the coal measures were formed giving the area hydrocarbon potential. After the Variscan Orogeny an unconformity occurred and then the Jurassic and Triassic rocks were seen as Breccia Conglomerates in the Ogmore and Portishead area.
In the Mendips the oldest rock is Old Red Sandstone, followed by Carboniferous Limestone. During the Variscan orogeny this got faulted and folded not an antiform. The Carboniferous Limestone has then been eroded down, with the sediments falling to the side of the hill (Fig.1) forming in Dolomitic Conglomerate and finally Keuper Marl is formed on top