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The article discusses the geochronological study of the trachyrhyolites of the Ulkan Group. It states that the volcanic deposits overlie metamorphic rocks of the Early Proterozoic era. It mentions that Riphean deposit sequence is considered as Siberian hypostratotype. It adds that isochronous Rb-Sr method was used to identify the age of the crust located at the base of Lower Riphean Uyan Group. Furthermore, the chemical composition of volcanites correspond to igneous rocks while associated granites and acid volcanites correspond to granites which are A-type.

The article discusses the method of isotope-geochronological timing of rock metamorphism at the boundary zone of Aldan Shield and the Dzhugdzhuro-Stanovoi Folded Area in the area of Nagornyi Village and Kholodnikan Pass in Russia. The method indicated an overthrust-sheet structure that developed in the zone and a tectonic plate that moderately points to the south. Further observations showed that the metamorphic rocks are deformed linearly or folded isoclinally in the latitudal direction parallel to the whole junction zone.