| Инд. авторы: | Turkina O.M., Berezhnaya N.G., Lepekhina E.N., Kapitonov I.N. |
| Заглавие: | U-Pb (SHRIMP II), Lu-Hf isotope and trace element geochemistry of zircons from high-grade metamorphic rocks of the Irkut terrane, Sharyzhalgay Uplift: Implications for the Neoarchaean evolution of the Siberian Craton |
| Библ. ссылка: | Turkina O.M., Berezhnaya N.G., Lepekhina E.N., Kapitonov I.N. U-Pb (SHRIMP II), Lu-Hf isotope and trace element geochemistry of zircons from high-grade metamorphic rocks of the Irkut terrane, Sharyzhalgay Uplift: Implications for the Neoarchaean evolution of the Siberian Craton // Gondwana Research. - 2012. - Vol.21. - Iss. 4. - P.801-817. - ISSN 1342-937X. - EISSN 1878-0571. |
| Внешние системы: | DOI: 10.1016/j.gr.2011.09.012; SCOPUS: 2-s2.0-84858622318; |
| Реферат: | eng: This paper presents new data on the bulk rock composition, petrogenesis and U-Pb zircon ages of high-grade metamorphic rocks and granitoids of the Irkut terrane, which is part of the Sharyzhalgay basement uplift located at the southwestern margin of the Siberian Craton. Our results allowed us to reliably constrain the Neoarchaean evolution of the southwestern Siberian Craton. The high-grade rocks under study are two-pyroxene (±amphibole) mafic granulites and orthopyroxene-bearing intermediate-felsic granulites. Both types of granulite are enriched in Ba, Th and LREE and both show clear Nb depletion, characteristics that are typical of subduction-related volcanic rocks. The mafic and felsic granulites contain magmatic zircons of 2698±9Ma and 2662±16Ma, respectively, indicating that most of the protoliths of the high-grade rocks formed in the Neoarchaean. The variable values of ε Nd (-4.8 to +1.2; whole rock) and ε Hf (-1.6 to +2.4; zircons) suggest contribution of older crust in the genesis of intermediate-felsic granulites. The relicts of ca. 3.4Ga older rocks have recently been recognized within the Irkut high-grade metamorphic complex. The petrological, geochemical and isotopic features of high-grade rocks are indicative of their protolith formation in a subduction-related setting at the margin of an older continental block. The metamorphic zircons in the high-grade rocks with ages of 2567±6 and 2540±10Ma and the zircons in the gneissic granitoids with an age of 2540±11Ma probably record Neoarchaean collisional events in the Irkut terrane. The coeval metamorphism (ca. 2.6Ga) and granitoid magmatism (ca. 2.54Ga) in the Irkut and Kitoy high-grade terranes of the Sharyzhalgay uplift suggest their Neoarchean collision, which resulted in the assembly of the Sharyzhalgay superterrane. Similarly, amalgamation of the ancient core of the Siberian Craton, which consisted of the West Aldan, Daldyn terranes and the two high-grade terranes of the Sharyzhalgay uplift, probably began in the Neoarchaean and was completed by ~2.0 to 1.85Ga. © 2011.
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| Ключевые слова: | U-Pb geochronology; Siberian Craton; Sharyzhalgay Uplift; Neoarchaean; High-grade rocks; |
| Издано: | 2012 |
| Физ. характеристика: | с.801-817 |