New age data for volcanic and plutonic complexes on the southwest of Primorye

Abstract

The paper deals with results of isotope-geochronological (U-Pb method based on zircon) study of volcanic rocks of the Talminsky complex as well as widespread intrusive formations from the southern part of the Laoeling-Grodekovo terrane in Southern Primorye, which are usually attributed to the Gamov and Gvozdevo complexes. The precision fresh U-Pb zircon ages obtained for the volcanic rocks of the Talminsky complex showed that their formation took place in a rather wide time interval (233-204 Ma) corresponding to the Carnian-Rhaetian stages of Late Triassic. U-Pb zircon dating of granitoids has revealed two phases of their intrusion. The first phase is dated late Permian–Middle Triassic (244-259 Ma) that coincides with the formation time of the Gamov complex. The existence of the second phase is a new discovery. Granitic rocks are dated to the Rhaetian stages of Late Triassic and assumed to be the intrusive facies of the Talminsky complex. As for granitoids of the Gvozdevo complex, the obtained ages refuted the Early Jurassic affiliation of these rocks.