Genetic and spatial links between porphyry and epithermal hydrothermal systems: A case study from Western Srednogorie, Bulgaria

Porphyry and epithermal deposits provide significant amounts of copper, molybdenum, gold, silver, and other elements. They form in the upper crustal levels and are related to sulfur- and water-rich intermediate to silicic magmatic sources of hydrothermal fluids. Western Srednogorie magmatic region is a part of the “Srednogorie volcano-intrusive zone” with Late Cretaceous age, assigned later to the Apuseni-Banat-Timok-Srednogorie metallogenic zone. The region is defined by several epithermal (Zlatusha, Milin Kamak, Pishtane, Krusha) and some porphyry (Bratushkovo, Dragotintsi) ore deposits and occurrences. Ore mineralization is related to the evolution of subduction generated magmas. In restricted areas of the Western Srednogorie, epithermal deposits are spatially associated with porphyry ones, as is the case with the epithermal Pishtane and porphyry Dragotintsi. This study provides field and some petrological data on the links between both deposits.