The Age of Gold Mineralization in the Yana–Kolyma Metallogenic Belt, Northeastern Russia: First Data of Re–Os Isotope Geochronology of Native Gold.

The first results of the study of the Re–Os isotope system of native gold from the orogenic Malo-Tarynskoe, Khangalas, and Bazovskoe deposits located in the central part of the Yana–Kolyma metallogenic belt are reported. The concentration of Re in the studied gold samples varies from 0.168 to 6.997 ppb, while the concentration of Os ranges from 0.068 to 1.443 ppb. The obtained data allowed us to calculate the isochrone age, which is consistent with the 40Ar–39Ar and K–Ar ages of sericite from these deposits within the error. The results indicate that the studied gold deposits were formed in the range of 147.8–137.1 Ma, synchronously with the Late Jurassic–Early Cretaceous orogenic processes in the Yana–Kolyma metallogenic belt and on the eastern margin of the Siberian Continent. The initial Os isotope ratios in the studied samples and fractions of gold from the Malo-Tarynskoe, Khangalas, and Bazovskoe deposits, (187Os/188Os)i = 0.1844–0.2475, suggest a significant role of a nonradiogenic component normally associated with mantle sources. [ABSTRACT FROM AUTHOR]