Data on the petrographic-geochemical and U-Th-Pb geochronological studies of granitoids of the Bukeschensky and Samyrsky massifs of small intrusions complex of the western part of the Yana-Kolyma gold belt are reported. The granitoids intruded terrigenous rocks of the Kular-Nera and Polousniy-Debin terranes and the Verkhoyansk fold and thrust belt. According to the U-Pb geochronological data obtained on zircons (SIMS SHRIMP-II), the granitoids were formed in the Early Cretaceous, in the interval of 144.5-143 Ma. Their geochemical characteristics are similar to the associated Late Jurassic (151-145 Ma) dikes of various composition of the Nera-Bokhapcha complex. The granitoids could have been formed from a mixed source with the participation of mantle (OIB- and E-MORB-type), subduction, or crustal components. The intrusion into the Early Cretaceous granitoids probably contributed to the final processes of migration and localization of gold in the Yana-Kolyma belt. Systems of tectonic faults of different orders, such as longitudinal (northwestern), Adycha-Taryn and others, and faults transverse to them (northeastern), also played in favor of this process.
