LEAD ISOTOPES IN GOLD DEPOSITS OF THE EASTERN SAYAN (RUSSIA)

The Eastern Sayan is a prospective gold ore district in Eastern Siberi a. It contains the rather large Zm-Holba gold deposit and several othe r ore deposits and occurrences that are confined to the Gargan Block o f the pre-Riphean basement. The results of comparative studies of the lead isotope system of ore galenas from ore deposits and occurrences o f the Urik-Kitoi gold ore district and from feldspars and rocks of the spatially related magmatic and metamorphic rocks are presented. The o btained isotopic-geochemical data suggest that the main ore source was the Late Archaean continental crust, remobilized during the Early pal eozoic metamorphism and granite formation processes, which stimulated ore formation.