Report on geophysical and geological surveys at Blackmount, Argyllshire

Blackmount, on the southern fringe of Rannoch Moor is largely drift covered but, where exposed, the underlying Precambrian Moine psammite contains granitic veins which probably stem from the adjacent (Devonian) Moor of Rannoch granite. These veins are generally pyritiferous and, at one locality, carry small amounts of molybdenite. Blackmount is also traversed by the Ericht-Laidon Fault, which, in theory, and by analogy with a similar fault to the south-east (the Tyndrum Fault), could be a site of significant sulphide mineralisation. Magnetic, very low frequency electro-magnetic (VLF EM), slingram EM and induced polarisation measurements carried out in the area of the veins suggest that the mineralisation has little or no lateral or depth continuation. Similar surveys were successful in locating the Ericht-Laidon Fault beneath drift, but suggest no associated mineralisation down to the greatest depth investigated.