Geophysical criteria for prospecting Au-Cu-Mo-porphyry stockwork deposits: case study of Kadilampi site in Western Karelia

The goal of the project is to study the Kadilampi granite massif located in therussian extension of Yalonvaara-Ilomantsi-Tuulos greenstone belt. It is known to host a cognominal Au-Cu-Mo-porphyry ore occurrence. To select geophysical criteria for prospecting similar massifs, experiments with the use of magnetometry, IP electrical profiling, resistance, and IP electrotomography methods were conducted. The granite massif was identified in host schist by the distribution patterns of the geomagnetic field and its resistance. The silicified stockwork zone with mineralization is faint negative according to IP parameter, but it creates elevated resistance anomalies upon electrical profiling. Based on the detailed study, using electrical tomography with reverse three-electrode set-ups, stockwork morphology was determined much more accurately. The most promising prospects with low-sulphide mineralization were delineated. The interpretation of the obtained geophysical data correlates well with drilling records. The proposed approach can be used for prospecting ore-bearing granite bodies and for identification of stockwork zones with Au-bearing Cu-Mo-porphyry mineralization.