Biogeochemical exploration for massive sulphide deposits in areas of dense vegetation: an orientation survey around the Kanköy Deposit (Trabzon, northeastern Turkey)

The eastern Pontides region is a mountainous terrain favourable for massive sulphide deposits. Besides the known deposits, it is highly likely that there are others to be discovered. This paper, therefore, describes the results of a soil and biogeochemical sampling program to assess the suitability of biogeochemical methods for the exploration of hidden deposits in temperate terrains. Soil sampling in the Pontides is shown to be a reliable follow-up method. It produced a significant geochemical response characterised by extensive Cu and Zn but localised Pb anomalies. Lead therefore is the element which can be used to pinpoint the mineralisation due to its relatively less mobile character. Hydromorphic dispersion enhanced the anomalies indicating that base of slope samples would produce reliable results. Of the plant species sampled, Corylus avellana (hazelnut tree) with deep penetrating roots shows comparable results to soil sampling and could be used to delineate the mineralisation. Rhododendron luteum may also be of help. In both species Pb shows limited dispersion and accumulates in the plants near the mineralised site whereas Cu and Zn tend to move away downslope. This shows that biogeochemical sampling could, with proper attention to species selection, be successfully used as an alternative method in the search of massive sulphide deposits in mountainous terrains with a high rainfall such as the eastern Pontides.