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VOLCANOGENIC FORMATION OF THE UYANDINO-YASACHNAYA MAGMATIC ARC IN THE MIDSTREAM OF THE INDIGIRKA RIVER (VERKHOYANSK-KOLYMA OROGENIC REGION)
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Vera Trunilina
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10.5593/sgem2022/1.1/s01.007
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10.5593/sgem2022/1.1
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1314-2704
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978-619-7603-38-5
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English
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22
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1.1
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• Prof. DSc. Oleksandr Trofymchuk, UKRAINE
• Prof. Dr. hab. oec. Baiba Rivza, LATVIA |
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Geology
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The Uyandino-Yasachnaya magmatic arc is the largest volcanic-plutonic belt in the north-east of Russia. However, there is yet to be a consensus on the nature of the arc, despite a long study of the rocks composing it. Most researchers consider it to be an island arc formation, however, some researchers also believe that it of a riftogenic or heterogeneous nature. The arc is composed of volcanogenic-sedimentary strata of variegated composition and associated subvolcanic formations. The rocks were formed during the Oxfordian-Volgian stage; their formation either preceded that of the Late Jurassic-Early Cretaceous granitoid massifs, or was synchronous with it. The research focused on volcanogenic and subvolcanic formations of the southeastern part of the arc in the midstream of the Indigirka River. The purpose of the research was to determine their composition and geodynamic conditions of formation. For this purpose, the study of the structure of volcanogenic strata and sub-volcanoes, their petrographic and chemical compositions, relations with granitoids was carried out. The volcanogenic strata within the territory are represented by two formations of rhyolite and their clastolavas: low-alkaline tholeiitic Oxfordian-Kimmeridgian formation and calcalkaline Medium Kimmeridgian – Early Volgian formation. The lower formation developed in the island-arc setting the upper formation developed under transitional conditions of the island-arc to the marginal-continental regime. The subvolcanic massifs have a dacite-rhyodacite composition; they intrude volcanogenic strata of both these suites and are metamorphosed near the contacts of the Early Cretaceous massifs. Their parental melt was produced at the boundary of amphibolite and dacite-tonalite substrates at maximum temperature (up to 1050oC) and pressure (up to 11.1 kbar). They are of Middle or Late Volga age and formed in the initial stages of the development of the active margin of the continent.
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volcanites, subvolcanites, formation conditions, age
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conference
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Proceedings of 22nd International Multidisciplinary Scientific GeoConference SGEM 2022
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22nd International Multidisciplinary Scientific GeoConference SGEM 2022, 04 - 10 July, 2022
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Proceedings Paper
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STEF92 Technology
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International Multidisciplinary Scientific GeoConference SGEM
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SWS Scholarly Society; Acad Sci Czech Republ; Latvian Acad Sci; Polish Acad Sci; Serbian Acad Sci and Arts; Natl Acad Sci Ukraine; Natl Acad Sci Armenia; Sci Council Japan; European Acad Sci, Arts and Letters; Acad Fine Arts Zagreb Croatia; Croatian Acad Sci and Arts; Acad Sci Moldova; Montenegrin Acad Sci and Arts; Georgian Acad Sci; Acad Fine Arts and Design Bratislava; Turkish Acad Sci.
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55-66
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04 - 10 July, 2022
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website
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8394
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