Culm Basin

To the south of the Mississippian platform carbonate successions of South Wales (Chapter 5) and Bristol, Mendips and Somerset (Chapter 6), Carboniferous rocks predominantly occur within the strongly deformed Culm synclinorial belt of Southwest England. The Culm Basin has a broad graben architecture, with an inner graben (Central Devon Sub-basin) flanked by half-grabens (Bideford and Launceston subbasins) (Fig. 4.1; Leveridge & Hartley 2006; Waters et al. 2009). The Bideford Subbasin is bounded to the north by the Brushford Fault, the Central Devon Sub-basin by the Greencliff Fault and the Launceston Sub-basin by the Rusey Fault. To the north of the Brushford Fault is the Northern Margin of the Culm Basin. The Tavy Basin has limited development of Famennian to Tournaisian strata. The High separating the Tavy Basin and Launceston Sub-basin includes a Tournaisian to ?Visean succession (Yeolmbridge and Laneast Quartzite formations). Remnants of Carboniferous strata also occur in the South Devon Basin.