Hypogenic Caves in the UK

The UK has a wide variety of hypogenic caves, including transverse maze caves, relict hydrothermal caves, gypsum mazes and hypogenic karst associated with water rising up deep thrust faults. While few of these are particularly extensive, they offer insights into the mechanisms of speleogenesis and mineralisation. The best developed hypogenic caves in the UK are in the Carboniferous limestones of northern England where at least nine network maze caves with plan lengths exceeding 1 km are known, almost all of which are accessible only via disused mine workings. In South Wales, relict hypogenic cave networks have been documented from cave systems surrounding the South Wales Coalfield. Hydrothermal cave systems are also known in the Bristol region in southern England, the Derbyshire Peak District and North Wales where they are associated with Pb–Zn mineralisation. In all three of these areas, active deep phreatic groundwater circulation is ongoing. Elsewhere in the UK, transverse artesian groundwater flow through Permo-Triassic gypsum in the Ripon area has led to the development of hypogenic cave systems and numerous sinkholes. This chapter documents for the first time all the known hypogenic cave systems found in the UK, discusses their modes of formation and outlines the potential for future discoveries.