Geological-Genetic Model of Svetlinskoye Gold–Telluride Deposit (Southern Urals)

Research subject. The Svetlinskoye gold–telluride deposit, the largest operating deposit in the Southern Urals, localized within the Svetlinskoye thrust zone of the Kochkar Anticlinorium. Aim. To develop a new geological-genetic model of the deposit based on the results of long-term research at the Svetlinskoye open pit. Materials and methods. The results of geological and structural observations in the open pit, geochemical and mineralogical research, 40 Ar/ 39 Ar isotopic dating of potassium-bearing minerals were analyzed. A review of literature sources was conducted. Results. The formation of the deposit was preceded by the emergence of a deep thrust (D 3 ) related to the onset of the Uralian collision, which destabilized the geological environment. The tectonic couple “thrust–buckling” was in operation, leading to the formation of the Anticlinorium, heating of rocks in its core, plastic and quasi-plastic deformations, growth of dome structures, zonal highgradient metamorphism, and deep metasomatic alterations of rocks. At early stages, a shallow marine basin emerged in the footwall of the thrust, accumulating terrigenous-carbonate sediments with numerous submarine landslide phenomena. The marine basin closed in the С 1v due to the formation of the Anticlinorium and uplift of the territory. The Svetlinsky dome, on whose western slope the deposit is located, played a key role in the localization and transformation of the ore cluster. The growth of the dome led to the deformation and partial destruction of the thrust zone, forming systems of tectonic detachments (thrusts), which became the main fluid-conducting and ore-hosting structures. Dome formation, zonal metamorphism, and granitization were associated with the mobilization and redistribution of ore components (Au, Te). The main ore-forming processes occurred at the early post-collisional stage, in the interval of 289–277 Ma. Conclusions. The structural preparation and ore-mobilizing processes during the formation of the Svetlinskoye deposit took place at the collisional stage (380–290 Ma), while ore deposition and deposit formation occurred in the interval of 289–277 Ma. The Svetlinsky dome played the main role in the formation and localization of the deposit; its formation was likely related to the emergence of deep thrusts under the conditions of the Late Paleozoic collision. This model provides a satisfactory explanation for the gold mineralization of periand inter-dome structures in the Kochkar Anticlinorium, thus indicating their priority for prospecting.