Geochemical characteristics of the Kal-e Kafi Cu-Mo-Au porphyry deposit, Central Iran

The Kal-e Kafi intrusive suite, located about 65 km northeast of Anarak Village in Central Iran is host to the significant un-tapped (virgin) Mo-bearing porphyry deposit. Trend-lines, fitted by linear regression, are plotted for values of vertical zonation coefficient (Kz) vs. elevation for the porphyry Cu-Mo deposits of Kal-e Kafi, Sungun (Iran), Aktogay (Kazakhstan), and Tekhut (Armenia). The slope of the trend-line at Kal-e Kafi deposit is much closer to horizontal, compared to the other deposits, signifying that the ore-body is preserved at subsurface. Geochemical anomalies, based on 121 samples, have been delineated and plotted over the 1:50,000 scale geological map of the study area. Contoured geochemical anomalies exceed 10,000 ppm for Pb, 2500 ppm for Zn, 20,000 ppm for Cu and 500 ppm for Mo. Previous work carried out by Technoexport used the “Cu-Mo Ore-Mineralization Vertical Zonation Coefficient” and the “Cu-Mo Ore-Mineralization Vertical Intensity Coefficient” to define fertile ore-bearing host rocks. The anomalies for Pb, Zn, Cu, and Mo, besides those determined by the abovementioned coefficients calculated by Soviet geologists, coincide with ore deposits used in this study. Grade-depth log interpretation of drill hole reveals that, at shallower depths, there are patterns of supergene sulfide enrichment, while at deeper intervals, primary sulfide stockwork mineralization occurs. Elevated Au/Ag values at same-depth intervals could be characteristic of the abovementioned mineralization types. Therefore, from a geochemical perspective, they could be considered as Pb-Zn-Cu±Au supergene sulfide enrichment and Cu-Mo±Au primary sulfide stockwork mineralization zones.