Problems of the Genesis of Deposits of the Ozerninsky Polymetallic Ore Cluster, Western Transbaikalia, Russia

The Ozerninsky ore cluster is a geological megastructure with unique rich and diverse mineralization. It hosts more than 20 deposits of lead, zinc, iron, copper, barite, and gold, including the Ozernoe polymetallic deposit, which has the largest Zn reserves of Russia. Our studies showed that many morphological features of ores of this deposit, which is ascribed to a hydrothermal–sedimentary type by most researchers, are ambiguous and include the signatures of metasomatic origin of sulfide mineralization. In addition to Pb–Zn deposits, the Ozerninsky ore cluster also contains complex gold–polymetallic, iron oxide (hematite–magnetite), and copper–barite deposits, the origin of which remains discussible. The presence of abundant exogenic gold deposits requires necessary estimation of gold potential of various types of endogenic ore mineralization as potential sources of noble metals. In spite of relatively long period of studies of the Ozerninsky ore cluster (more than half a century), many questions of proportions between various mineralization types, age and genesis of ores, and geodynamic formation settings of the deposits are still a matter of debate. The solution of these questions requires more detailed geochronological and lithological–stratigraphic studies in combination with study of mineral composition of ores, their isotopic–geochemical characteristics, and physicochemical formation conditions.