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The isotopic U–Pb ages are estimated for zircons (for the first time by the LA–ICP–MS method) from biotite (Eldzhurty) granites and for the first time from the rhyolites at the giant Tyrnyauz Mo–W deposit (North Caucasus). The weighted mean isotopic U–Pb age of zircon from the Eldzhurty granites is 2.10 ± 0.08 Ma, with variations from 1.78 to 2.53 Ma, whereas that of zircon from the rhyolites is 2.05 ± 0.04 Ma, with variations from 1.81 to 2.42 Ma. These data confirm the Neogene (Pleistocene) age of the rock crystallization, are in agreement with the emplacement sequence, and emphasize the short time span (~50 ky) between them. [ABSTRACT FROM AUTHOR]

The first data of a U–Pb isotopic study (LA-ICP-MS method) of zircon from leucocratic granites of the giant Tyrnyauz Mo–W deposit (North Caucasus) are presented. The emplacement of this granite separated the formation stages of Mo–W skarns and younger large stockworks with Mo-mineralization. Two types of zircons are distinguished among the grains identified. The first type is represented by rare tabular and short-prismatic crystals (xenocrysts) of an ancient zircon, with large variations of the U–Pb isotopic age (from about 300 Ma to almost 1500 Ma). The second type includes more abundant long-prismatic crystals of a young zircon; its weighted average U–Pb isotopic age (2.67 ± 0.04 Ma) corresponds to the time of leucocratic granite crystallization. [ABSTRACT FROM AUTHOR]

The Late Albian–Early Cenomanian epoch of Au-Cu porphyry ore mineralization has been distinguished within the Sikhote-Alin. The development of ore mineralization is associated with Albian–Cenomanian granitoids, synchronous to syn-strike-slip orogenesis and the formation of the continental lithosphere in the setting of transform continental margins. The development of Au–Mo–Cu and Cu–Au–W types of ore mineralization in the terrains of the Jurassic accretionary prism and the Early Cretaceous terrain of the epioceanic turbidite basin, correspondingly, was induced with the mantle–crustal synorogenic intrusions of granitoids. The U–Pb zircon dates (100–95 Ma, Albian–Cenomanian) of Au–Cu porphyry Malmyzh granitoids are given for the first time. The similar data available on the age of granitoids in Eastern and Southeastern Asia, which are associated with plutonogenic–hydrothermal deposits of Cu, Au, Sn and other metals, allow us to suggest that there is an Albian–Cenomanian metallogenic megabelt extending along the entire Pacific continental margin of Asia. [ABSTRACT FROM AUTHOR]