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.