Инд. авторы:	Nozhkin A.D., Turkina O.M., Sayko K.A.
Заглавие:	Geochemistry and Isotope Composition of Paleoproterozoic Granites and Felsic Volcanics of the Elash Graben: Evidence of the Heterogeneity of the Early Precambrian Crust
Библ. ссылка:	Nozhkin A.D., Turkina O.M., Sayko K.A. Geochemistry and Isotope Composition of Paleoproterozoic Granites and Felsic Volcanics of the Elash Graben: Evidence of the Heterogeneity of the Early Precambrian Crust // Russian Geology and Geophysics. - 2021. - Vol.62. - Iss. 10. - P.1175-1187. - ISSN 1068-7971. - EISSN 1878-030X.
Внешние системы:	DOI: 10.2113/RGG20204206; WoS: 000710871700006;
Реферат:	eng: The paper presents results of a petrogeochemical and isotope-geochronological study of the granite-leucogranite association of the Pavlov massif and felsic volcanics from the Elash graben (Biryusa block, southwest of the Siberian craton). A characteristic feature of the granite-leucogranites is their spatial and temporal association with vein aplites and pegmatites of the East Sayan rare-metal province. The U-Pb age of zircon from granites of the Pavlov massif (1852 +/- 5 Ma) is close to the age of the pegmatites of the Vishnyakovskoe rare-metal deposit (1838 +/- 3 Ma). The predominant biotite porphyritic granites and leucogranites of the Pavlov massif show variable alkali ratios (K2O/Na2O = 1.1-2.3) and ferroan (Fe*) index and a peraluminous composition; they are comparable with S-granites. The studied rhyolites of the Tagul River (SiO2 = 71-76%) show a low ferroan index, a high K2O/Na2O ratio (1.6-4.0), low (La/Yb) n values (4.3-10.5), and a clear Eu minimum (Eu/Eu* = 0.3-0.5); they are similar to highly fractionated I-granites. All coeval late Paleoproterozoic (1.88-1.85 Ga) granites and felsic volcanics of the Elash graben have distinct differences in composition, especially in the ferroan index and HREE contents, owing to variations in the source composition and melting conditions during their formation at postcollisions extension. The wide range of the isotope parameters of granites and felsic volcanic rocks (epsilon(Nd) from +2.0 to -3.7) and zircons (epsilon(Hf) from +3.0 to +0.8, granites of the Toporok massif) indicates the heterogeneity of the crustal basement of the Elash graben, which formed both in the Archean and in the Paleoproterozoic.
Ключевые слова:	Nd isotope composition; Paleoproterozoic juvenile crust; southwestern Siberian craton; SIBERIAN CRATON; VOLCANOPLUTONIC BELT; MARGIN; PEGMATITES; AGE; ZIRCON; BIRYUSA BLOCK; granitoids; SHARYZHALGAI UPLIFT; felsic volcanics;
Издано:	2021
Физ. характеристика:	с.1175-1187