Z.V. KRUPENIK (VSEGEI)

Gold-­bearing metasomatite of the Yalonvara Pertinjarvi greenstone structure (Western Karelia)

The relationship between gold mineralization and metasomatic haloes is characterized on the example of the Pertinjarvi and Soanvara prospective areas of the Yalonvara­-Pertinjarvi greenstone structure (Western Karelia). The main type of ore-­bearing metasomatites of area are beresites. The spatial and genetic connection of beresites with acidic volcanics of the yalonvarskaya suite have been established. Petrographic characteristics of beresites and beresitized rocks have been given. The zonation of metasomatic haloes has been characterized. A second type of metasomatic transformation, represented by a garnet-­epidote-­biotite-­quartz mineral paragenesis, superimposed on the outer zones of the haloes of beresitization was established. Two types of gold mineralization have been allocated. The first one, represented by rich ores, is localized in quartz veins and hydrothermal breccias. The second type, with a low gold content, is confined to the periphery of the haloes of beresitization, in the thin veins (stockwork) with garnet­-epidote-­biotite selvages.
Keywords: Karelia, greenstone belt, Archean, metasomatoz, beresite, volcanic rocks, metasomatic zonation, gold mineralization.