N. Volkova, E. Mikheev, A. Travin, A. Vladimirov, A. Mekhonoshin, V. .. Khlestov
{"title":"P–T CONDITIONS, U/Pb AND 40Ar/39Ar ISOTOPIC AGES OF UHT GRANULITES FROM CAPE KALTYGEI, WESTERN BAIKAL REGION","authors":"N. Volkova, E. Mikheev, A. Travin, A. Vladimirov, A. Mekhonoshin, V. .. Khlestov","doi":"10.5800/gt-2021-12-2-0526","DOIUrl":null,"url":null,"abstract":"The study is focused on metapelitic granulites of Cape Kaltygei (Western Baikal region) that contain a diagnostic mineral assemblage of ultrahigh temperature (UHT) metamorphic rocks (orthopyroxene+sillimanite+quartz). The pseudosection-based thermobarometry yields peak metamorphic temperature and pressure values (T=950 °C, P=~9 kbar) and suggests near-isobaric cooling (IBC) conditions during the retrograde evolution of the granulites. The U/Pb zircon age estimates for metamorphism (~1.87 Ga) support the data published by other researchers. The SHRIMP-II U-Pb dating of zircon cores yields a minimum protolith age of 1.94–1.91 Ga. Biotites and amphiboles from granulites of Cape Kaltygei show the 40Ar/39Ar isotopic ages that are close to the Early Paleozoic accretion-collision system of the Western Baikal region.","PeriodicalId":44925,"journal":{"name":"Geodynamics & Tectonophysics","volume":null,"pages":null},"PeriodicalIF":0.8000,"publicationDate":"2021-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geodynamics & Tectonophysics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.5800/gt-2021-12-2-0526","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 2
Abstract
The study is focused on metapelitic granulites of Cape Kaltygei (Western Baikal region) that contain a diagnostic mineral assemblage of ultrahigh temperature (UHT) metamorphic rocks (orthopyroxene+sillimanite+quartz). The pseudosection-based thermobarometry yields peak metamorphic temperature and pressure values (T=950 °C, P=~9 kbar) and suggests near-isobaric cooling (IBC) conditions during the retrograde evolution of the granulites. The U/Pb zircon age estimates for metamorphism (~1.87 Ga) support the data published by other researchers. The SHRIMP-II U-Pb dating of zircon cores yields a minimum protolith age of 1.94–1.91 Ga. Biotites and amphiboles from granulites of Cape Kaltygei show the 40Ar/39Ar isotopic ages that are close to the Early Paleozoic accretion-collision system of the Western Baikal region.
期刊介绍:
The purpose of the journal is facilitating awareness of the international scientific community of new data on geodynamics of continental lithosphere in a wide range of geolchronological data, as well as tectonophysics as an integral part of geodynamics, in which physico-mathematical and structural-geological concepts are applied to deal with topical problems of the evolution of structures and processes taking place simultaneously in the lithosphere. Complex geological and geophysical studies of the Earth tectonosphere have been significantly enhanced in the current decade across the world. As a result, a large number of publications are developed based on thorough analyses of paleo- and modern geodynamic processes with reference to results of properly substantiated physical experiments, field data and tectonophysical calculations. Comprehensive research of that type, followed by consolidation and generalization of research results and conclusions, conforms to the start-of-the-art of the Earth’s sciences.