Geochemical and geophysical investigations in Exmoor and the Brendon Hills

A programme of geochemical and geophysical study was started in 1971 to assess the mineral potential of the Exmoor area. Drainage geochemistry over both Exmoor and the Brendon Hills indicated areas of anomalous metal concentrations in stream sediments which call for further investigation. Some of these anomalies undoubtedly relate to vein style mineralisation, but others probably reflect a stratiform distribution of ore metals. Barium anomalies have also been recognised and these are presumed to indicate previously unrecorded veins of barite. Investigation of an aeromagnetic anomaly which trends WNW - ESE over the upland areas resolves it into shallow and deep components. The source of the more deepseated magnetic anomaly remains uncertain but two diamond drill holes showed the shallow source to be pyrrhotite mineralisation in the form of disseminations and veinlets. Detailed soil geochemistry was carried out over some of the aeromagnetic anomalies.