Morozkinskoye gold deposit (southern Yakutia): age and ore sources

The paper presents the results of the comprehensive isotope geochemical (Re-Os, Pb and δ34S) study of sulfide mineralization of the Morozkinskoye deposit. The ore zones of the deposit are localized in the syenite massif of Mount Rudnaya, which is located within the Central Aldan ore region (southern Yakutia). Gold mineralization is represented by vein-disseminated or vein type mineralization and is manifested in acidic low-temperature metasomatites – beresites (Qz-Ser-Ank-Py). For the first time we obtained an age estimate of the gold mineralization ~ 129 ± 3 Ma, which the synchronism of the hydrothermal ore process in the beresites, which formed the Morozkinskoye deposit, and magmatic crystallization of the syenites of Mount Rudnaya (~130 Ma). The osmium initial isotopic composition of the studied sulfides indicates a mixed mantle-crustal source of sulfide mineralization. New lead isotopic data of syenites indicate the predominance of mantle lead and an insignificant role of the lower – crust lead, while the isotopic composition of pyrite denotes the presence of the upper crustal material in the ore genesis. The sulfide δ34S values vary from –2.3 to +0.6 ‰ and indicate a predominantly magmatic source of sulfur in the ores.