| Инд. авторы: | Turkina O.M., Urmantseva L.N., Berezhnaya N.G., Skublov S.G. |
| Заглавие: | Formation and Mesoarchean metamorphism of hypersthene gneisses from the Irkut granulite-gneiss block (Sharyzhalgai uplift in the southwestern Siberian craton) |
| Библ. ссылка: | Turkina O.M., Urmantseva L.N., Berezhnaya N.G., Skublov S.G. Formation and Mesoarchean metamorphism of hypersthene gneisses from the Irkut granulite-gneiss block (Sharyzhalgai uplift in the southwestern Siberian craton) // Russian Geology and Geophysics. - 2011. - Vol.52. - Iss. 1. - P.97-108. - ISSN 1068-7971. - EISSN 1878-030X. |
| Внешние системы: | DOI: 10.1016/j.rgg.2010.12.008; SCOPUS: 2-s2.0-78650769626; |
| Реферат: | eng: U-Pb dating (SHRIMP-II) and study of the internal structure and composition were carried out for zircon from hypersthene gneiss from the Irkut granulite-gneiss block (Sharyzhalgai uplift in the southwestern Siberian craton). Three generations of zircon have been revealed in the hypersthene gneiss, which differ in zoning pattern, U and Th concentrations, and REE distribution. Zircon cores with growth zoning relics show a REE pattern typical of magmatic zircon: with a high (Lu/Gd)n value (11-36) and a distinct Ce anomaly (Ce/Ce* = 15-81). They belong to early magmatic generation with an age of ≥3.16 Ga. Multifaced soccerball crystals, rims, and unzoned cores of zircon belong to metamorphic generation; they are depleted in REE and show a lower (Lu/Gd)n value (1.1-9.2) than the magmatic cores. This zircon generation formed as a result of the Mesoarchean high-temperature metamorphism at ~3.04 Ga. The latest zircon generation includes thin outer rims with low (Lu/Gd)n (11-12.4) and Th/U (0.02-0.05) values and long-prismatic crystals with an oscillatory zoning, which resulted from the Paleoproterozoic (~1.85 Ga) granulite metamorphism and partial melting. The different ages of high-temperature metamorphism in the granulite-gneiss (~3.04 and 2.55-2.6 Ga) and granite-greenstone (~3.2 Ga) blocks of the Sharyzhalgai uplift reflect the independent tectonothermal and geodynamic evolution of crust in these structures, up to the final amalgamation in the Paleoproterozoic (1.88-1.85 Ga). © 2010.
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| Ключевые слова: | Siberian Craton; Russian Federation; zoning; zircon; uranium-lead dating; uplift; tectonic evolution; Proterozoic; partial melting; metamorphism; Decapoda (Crustacea); gneiss; geodynamics; chemical composition; Archean; Zircon composition; U-Pb age; Siberian craton; Sharyzhalgai uplift; Paleoarchean; Granulite-gneiss complex; granulite; |
| Издано: | 2011 |
| Физ. характеристика: | с.97-108 |