Инд. авторы:	Rudnev S.N., Mal'kovets V.G., Belousova E.A., Tret'yakova I.G, Serov P.A., Kiseleva V.Y., Gibsher A.A., Nikolaeva I.V.
Заглавие:	Geochemistry, Sm-Nd, Rb-Sr, and Lu-Hf Isotopes, Sources, and Conditions of Formation of Early Paleozoic Plagiogranitoids in the South of the Lake Zone in Western Mongolia
Библ. ссылка:	Rudnev S.N., Mal'kovets V.G., Belousova E.A., Tret'yakova I.G, Serov P.A., Kiseleva V.Y., Gibsher A.A., Nikolaeva I.V. Geochemistry, Sm-Nd, Rb-Sr, and Lu-Hf Isotopes, Sources, and Conditions of Formation of Early Paleozoic Plagiogranitoids in the South of the Lake Zone in Western Mongolia // Russian Geology and Geophysics. - 2020. - Vol.61. - Iss. 2. - P.119-138. - ISSN 1068-7971. - EISSN 1878-030X.
Внешние системы:	DOI: 10.15372/RGG2019087; WoS: 000514081000001;
Реферат:	eng: We present results of geochemical and isotope (Rb-Sr, Stn-Nd, and Lu-Hf) studies of the early Paleozoic plagiogranitoid associations in the south of the Lake Zone in Western Mongolia, which formed at the island-arc and accretion-collision stages of the regional evolution. According to the petrogeochemical composition, the early Paleozoic plagiogranitoid associations of the island-arc (Tugrug, Hatan-Hunga, Udzur-Hunga, and Bayasgalant plutons, 531-517 Ma) and accretion-collision (Tugrug, Mandalt, and Dut Uul plutons, 504-481 Ma) stages are high- and low-alumina rocks. The recognized types of plagiogranitoids, with regard to their trace-element composition, indicate that their parental melts were generated from MORB-type metabasites at >= 10-12 kbar, in equilibrium with garnet-containing restite, and at <= 8 kbar, in equilibrium with plagioclase-containing restite. The Sr-Nd isotope data on the rocks and the Lu-Hf isotope parameters of their magmatic zircons show two groups of plagiogranitoids, with different sources of melts. The first group includes plagiogranitoid associations of most plutons (Tugrug, Udzur-Hunga, Hatan-Hunga, Bayasgalant, and Dut Uul) with isotope parameters (epsilon(Nd )= 8.5-4.6, (Sr-87/Sr-86), = 0.7034-0.7036, and epsilon(Hf) = 14.7-11.9) indicating the juvenile nature of their sources. The second group includes plagiogranitoids of the Mandalt pluton; their isotope parameters (epsilon(Nd) = 1.4-0.2, (Sr-87/(86) Sr)(0) = 0.7053, and e(Hf) = 7.2-5.4) indicate that the parental melts were generated mostly from enriched-mantle metabasites. The Hf isotope data on inherited and xenogenic zircons (664-519 Ma) from the early Paleozoic plagiogranitoid associations of the southern Lake Zone permit us to separate these rocks into three groups according to their epsilon(Hf) values (14.5-12.8, 2.9, and 10.6-6.7). The Hf isotope parameters of magmatic and inherited zircons, with regard to their age, indicate that the source of the parental melts lacked rocks with a long crustal history, such as the early Precambrian associations of the Dzavhan microcontinent.
Ключевые слова:	Nd-Sr-Hf isotopy; Central Asian Orogenic Belt; Lake Zone in Western Mongolia; ASIAN OROGENIC BELT; CONTINENTAL GROWTH; MAGMATISM; ADAKITE; CALEDONIDES; GEOCHRONOLOGY; EVOLUTION; GRANITOIDS; MECHANISMS; granitoid magmatism; CRUST; geochemistry;
Издано:	2020
Физ. характеристика:	с.119-138