Granites of the Middle Jurassic Ariadnenskii Ultrabasite-Basite Intrusion in the Jurassic Accretionary Prism (Sikhote-Alin, Russia)

The paper presents first geochronological and petrogeochemical data on the Middle Jurassic granites of the metalliferous Ariadnenskii ultrabasite-basite intrusion in the Sikhote-Alin Orogenic Belt. These granites with U–Pb zircon ages of 165.2 ± 1.1 and 165.48 ± 1.1 Ma are highly differentiated A-type rocks formed as a result of the melting of terrigenous rocks during the intrusion of an ultrabasite-basite OIB melt into an accretionary prism. The results obtained confirm the hypothesis of a possible rise of asthenospheric material from under a sinking oceanic plate in an unusual geodynamic setting.