| Инд. авторы: | Kuibida M.L., Murzin O.V., Kruk N.N., Safonova I.Y., Sun M., Komiya T., Wong J., Aoki S., Murzina N.M., Nikolaeva I.V., Semenova D.V., Khlestov M.V., Shelepaev R.A., Kotler P.D., Yakovlev V.A., Naryzhnova A.V. |
| Заглавие: | Whole-rock geochemistry and U-Pb ages of Devonian bimodal-type rhyolites from the Rudny Altai, Russia: Petrogenesis and tectonic settings |
| Библ. ссылка: | Kuibida M.L., Murzin O.V., Kruk N.N., Safonova I.Y., Sun M., Komiya T., Wong J., Aoki S., Murzina N.M., Nikolaeva I.V., Semenova D.V., Khlestov M.V., Shelepaev R.A., Kotler P.D., Yakovlev V.A., Naryzhnova A.V. Whole-rock geochemistry and U-Pb ages of Devonian bimodal-type rhyolites from the Rudny Altai, Russia: Petrogenesis and tectonic settings // Gondwana Research. - 2020. - Vol.81. - P.312-338. - ISSN 1342-937X. - EISSN 1878-0571. |
| Внешние системы: | DOI: 10.1016/j.gr.2019.12.002; РИНЦ: 43242376; WoS: 000523559700010; |
| Реферат: | eng: The paper presents new original data on the Devonian felsic volcanism of the NW Rudny Altai (Russia) in the west of Central Asian Orogenic Belt (CAOB) - the front part of the Altai convergent margin of the Siberian continent. Two geochemical types of subvolcanic rhyolites were emplaced synchronously with the bimodal rhyolitebasalt association, which began to form in the end-Emsian, and clearly manifested on the border of the Givetian and the Frasnian. The rhyolites yield zircon U-Pb ages of ca. 390 Ma (R1-type) and 380 Ma (R2- and R3-types), reflecting two peaks of the volcanic activity. Most of these rocks have extreme petrochemical characteristics of high SiO2 contents and have contrast Na/K ratios. Their compositions are transition between talc-alkaline and tholeiite series: (12/Yb)(n) - 2-7, Zr/Y - 4 (Zr < 350 ppm) and la/Sm - 055-1. Rhyolites bear the distinctive geochemical signature of A-type felsic magma, such as enrichments in Zr, Nb, Y and Ce (>350 ppm), Zr (>250 ppm), and high Ga/AI (>2.6) values. The island-arc-like R1-rhyolite formed immediately after the beginning of rifting due to widespread crustal melting under reduced conditions. The generation of rift-like R2- and R3-rhyolites took place under non-equilibrium conditions, synchronously with the rise in the upper crust of GivetianFrasnian basic magmas, as a result of the active lithospheric extension and high thermal input from the underlying hot mantle. We propose an extension regime in the transition area between the island-arc and back-arc basin for the origin of rhyolites. The study of the Devonian volcanism of the Rudny Altai gives important information about the processes that occurred at the initial stage of the formation of the Altai convergent margin. (C) 2020 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
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| Ключевые слова: | ICP-MS; CRUSTAL GROWTH; SILICIC MAGMAS; LACHLAN FOLD BELT; NW CHINA PETROGENESIS; MASSIVE SULFIDE DEPOSITS; TAUPO VOLCANIC ZONE; ASIAN OROGENIC BELT; A-TYPE GRANITES; Central Asian Orogenic Belt; Melnichno-Sosnovsky volcanic complex; Bimodal basalt-rhyolite association; Back-arc basin; Rifled-arc; EXPERIMENTAL CONSTRAINTS; |
| Издано: | 2020 |
| Физ. характеристика: | с.312-338 |