Mineral exploration in the area around Culvennan Fell, Kirkcowan, south-western Scotland

Reconnaissance geochemical and geophysical surveys were carried out in the area of Culvennan Fell to investigate the possibility of porphyry copper mineralisation associated with the Culvennan diorite. Work was concentrated on the west of the intrusion where numerous dykes, mainly of intermediate composition, and three small bodies of intrusion breccia intrude folded greywacke, quartz-wacke, silty mudstone, siltstone and calcareous mudstone of the Silurian Gala Group. A zone of high chargeability was defined within which there are areas of low resistivity and narrow magnetic anomalies. The cause of these anomalies is most likely to be stratabound concentrations of sulphides within the sedimentary succession and the dykes, and there is no evidence to show that the high chargeability is associated with porphyrystyle mineralisation. The results of the geochemical survey substantiate this, though minor secondary concentrations of metals and weak, local copper-arsenid-iron-lead mineralisation were indicated.