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Based on the results of Sm-Nd isotopic geochemical and U-Th-Pb geochronological LA-ICP-MS studies, it has been established that the formation of metamorphic rock protoliths of the Stanovoi Complex in the western Dzhugdzhur-Stanovoi Superterrane of the Central Asian Foldbelt took place over the following time spans: 2750-2860 Ma (Ilikan Group of the Ilikan Zone), 1890-1910 Ma (Bryanta Group of the Bryanta Zone), and ~2.0 Ga (Kupuri and Zeya groups of the Kupuri and Zeya zones, respectively). It has been shown that the western part of the Dzhugdzhur-Stanovoi Superterrane was formed ~1.9 Ga ago, as a result of collision of the Neoarchean Ilikan Terrane, the Paleoproterozoic island arc, and the Paleoproterozoic Kupuri-Zeya Terrane. The data make it possible to consider the Kurul'ta, and Zverevo blocks of the Stanovoi Structural Suture and the Ilikan Terrane of the Dzhugdzhur-Stanovoi Superterrane of the Central Asian Foldbelt as constituents of a common terrane. [ABSTRACT FROM AUTHOR]

U-Pb zircon isotopic data on rocks from the Kandalaksha-Umba zone of the Lapland granulite belt in the Por'ya Bay area constrain the age of the protolith of the apodacite (apotonalite) Opx- Bt granulite gneisses at 2799 ± 4 Ma, and the age of the apogabbronorite Grt- Opx- Cpx- Hbl crystalline schists at 2315 ± 23 Ma. The U-Pb sphene age of the magmatic crystallization of the postmetamorphic granodiorites is 1901 ± 5 Ma. The zircon yields the U-Pb age of the contamination of xenogenic zircons, which were captured during the dissolution of xenoliths of the host Grt- Opx- Cpx- Hbl crystalline schists in granodiorite melt. The comparison of the most important attributes of the endogenic histories of the adjacent Lapland Granulite and Belomorian Mobile belts testifies to their similar evolutionary histories: (1) the protolith age of the acid Opx- Bt granulites of the Lapland Belt (2799 ± 4 Ma) coincides with the protolith age of acid gneisses in the Belomorian Belt (2890-2690 Ma); (2) the ages of the gabbronorite protolith of Grt- Opx- Cpx- Hbl granulites in the Lapland Belt (2315 ± 23 Ma) and gabbro-anorthosite in the Kolvitsa Massif (2462-2423 Ma) are close to the protolith age of eclogitized gabbronorites in the Belomorian coronite suite (2.46-2.36 Ga); (3) the age of granulite metamorphism of acid and mafic rocks in the Lapland Belt is 1912-1925 Ma, and the age of eclogite metamorphism of gneisses and metabasites in the Belomorian Belt is approximately 1.9 Ga, i.e., their metamorphism took place in Svecofennian time; (4) the peak pressure of granulite metamorphism in the Lapland Belt was 9-11 kbar at a temperature of 800-850°C, whereas the peak metamorphic parameters of eclogite metamorphism in the Belomorian Belt were 10-12 kbar and 640-700°C. This means that the metamorphic complexes of the Lapland and Belomorian belts had the same Mezo- and Neoarchean protoliths hosting bodies of Paleoproterozoic gabbroids and were completely formed largely by a single cycle of Svecofennian high-pressure zonal metamorphism within a temperature range from the lowest grade of the eclogite to the granulite facies. [ABSTRACT FROM AUTHOR]

U-Pb (LA-ICPMS) geochronological studies established the minimum age of detrital zircons from metasedimentary rocks of the Uril Formation of the Amur Group of ∼240 Ma, which approximately corresponds to the lower age boundary of formation of their protoliths. The upper boundary of accumulation of sedimentary rocks of this formation is governed by the age of superimposed structural-metamorphic transformations (220-210 Ma). It follows that the age of protoliths of metasedimentary rocks of the Uril Formation is Triassic in contrast to the previously suggested Early Precambrian age. At the same time, previous estimations of the Nd model age of metasedimentary rocks of the Tulovchikha Formation of the Amur Group and intruding gabbroic rocks are 1.7 and 0.5 Ga, respectively. In other words, the age of this formation is 1.7-0.5 Ga. All of this indicates a combination of sedimentary and volcanic rocks of different ages in the section of the Amur Group. Judging from the Lu-Hf isotopic-geochemical studies of zircons, the major sources of protoliths for metasedimentary rocks of the Uril Formation are Neoproterozoic igneous rocks and also Early and Late Paleozoic and Early Mesozoic igneous rocks, the formation of which was related to the reworking of the Neo- and Mesoproterozoic continental crust. [ABSTRACT FROM AUTHOR]

The article presents information on a study which determines the age of the protolith for metamorphic rocks of the Gonzha Group. It provides information on Gonzha Group which unites metamorphic rocks of the tectonic block located in the north-eastern part of the Argun terrane in the Central Asian fold belt. It reveals that uranium-lead (U-Pb) geochronological and Lutetium-Hafnium (Lu-Hf) isotopic-geochemical investigations of detrital zircons from metasedimentary rocks of the Gonzha Group were performed in the study. A graph with concordia for zircons from meta-sedimentary rocks of the Gonzha Group is presented. A geological map is also presented.