МИНЕРАЛОГИЯ И УСЛОВИЯ ФОРМИРОВАНИЯ ЗОЛОТО РУДНЫХ ПРОЯВЛЕНИЙ КОСТОМУКШСКОЙ СТРУКТУРЫ ПО ДАННЫМ ГАЗОВО-ЖИДКИХ ВКЛЮЧЕНИЙ

Abstract

In the Kostomuksha structure, gold ore mineralization is represented by Taloveis ore deposit, Faktomoye, Berendci, Zapadnaya Ruvinvaara, Niemijarvi, Vostochnoye, Kurgelampi ore occurrences; it was found also in the open-pit of Kostomuksha iron ore deposit. All these occurrences belong to different genetic types associated with zones of hydrothermal alteration in acid volcanites and banded iron ore formation, with halleflinta, with the Taloveis diorite-granite-porphyry complex and/or with metasomatized shear zones in spots favorable for the gold deposition. Minerals of gold-bearing massive pyrite ores are represented by pyrrhotitc, pyritc and less common chalcopyrite, with gold, molybdenite and bismuthinc. Gold-sulphide and gold-quartz ores of the Taloveis area contain pyrite and less common chalcopyrite, sphalerite, galena, arsenopyrite and gold; gold-quartz ores of the Main vein there carry pyrite of two generations, gold, chalcopyrite, galena, sphalerite and bismuthotellurides (tsumonite and sulphotsumonitc). In addition, arsenopyrite and scheelite were identified in the Berendei ore occurrence. Ores from Vostochny and Kurgelampi localities contain pyrrhotite, molybdenite and bismuthine. Para-genesis of pyrrhotite, arsenopyrite, chalcopyrite and gold is typical for quartz veins in the iron ore deposit. Study of fluid inclusions in quartz has allowed to define composition and density of the fluids. These data have confirmed the concept of the two-stage formation of Taloveis deposit: while beresitization at the early stage, and under decreasing pressure and temperature, with changing composition of the fluid, at the collision stage of the territory evolution - where submeridional quartz veins were formed.