A review of intermediate sulfidation epithermal deposits and subclassification / Обзор эпитермальных отложений месторождений формации "средне-сульфидных" ("средне-серных") и их подклассификация

Intermediate sulfidation (IS) veins is one of the subtypes of epithermal deposits formed in subduction-related arc settings or post-collisional orogenic belts. The economic and scientific significance of IS deposits has been highlighting importance in Ag-Au-Pb-Zn exploration and study of porphyry-epithermal systems. This epithermal clan of deposits typically have a close relationship with andesitic-dacitic volcanic-subvolcanic rocks, and formed at a depth of ∼0.3 to as much as 1 + km. IS deposits are typically related to oxidized calcic to calc-alkaline magmatism. Fluid homogenization temperatures and salinities range between 150 and 350 °C, and 0 and 23 wt% NaCl equivalent, respectively. The O and H isotope compositions are consistent with a mixture of magmatic and meteoric water, with an increase in meteoric diluent as the hydrothermal system wanes. Most of the IS deposits in the world, particularly those in Circum-Pacific metallogenic belts, formed during Cenozoic time. Several Mesozoic and Paleozoic IS deposits in the Central Asian Orogenic Belt imply great exploration potential for preCenozoic IS deposits in this area <...>