Sharkham Iron Mine
Designations: SSSI, Proposed CGS/RIGS
The former mine workings reveal a form of mineralisation that is virtually unique to the region
GCR block / key theme: Mineralogy
Associated SSSI: Berry Head to Sharkham Point SSSI
Geological / geomorphological features: [Provisional] Sharkham Iron Mine is a remarkable but little known geological site. The deposit is characterised by hematite replacement of Devonian limestones, associated with limestone breccias and localised developments of botryoidal goethite, limonite and hematite. Some surfaces show patches and radiating crystals of white and pink barite. The source of the iron was almost certainly from Permian ‘red beds' in the area, probably via circulating hot fluids migrating along fractures. The process of replacement is likely to be similar to that known in South Wales, where iron minerals replace zones in Lower Carboniferous limestones close to an unconformity with Triassic red-beds. Although the former opencast workings are largely filled in, good exposures remain in the coastal slope.
Reasons for proposal as a CGS / RIGS sites: The former mine workings reveal a form of mineralisation that is virtually unique in the region, and which postdates the better known Variscan phase of metallogenesis in south-west England. An important site with an associated cultural significance, although requiring improvements to access to realise its full educational potential.