The urosozero greenstone structure (Fennoscandian shield): geology, composition, age and metamorphism of the volcanics

• Main Authors: Наталия Александровна Арестова, Анастасия Владимировна Юрченко, Валерий Петрович Чекулаев, Светлана Борисовна Лобач-Жученко, Глеб Алексеевич Кучеровский, Елена Николаевна Лепехина, Natalia Arestova, Anastasia Yurchenko, Valery Chekulaev, Svetlana Lobach-Zhuchenko, Gleb Kucherovsky, Elena Lepekhina
• Format: Article
• Language: English
• Published: Karelian Research Centre of the Russian Academy of Sciences 2016-03-01
• Series: Transactions of the Karelian Research Centre of the Russian Academy of Sciences
• Subjects: балтийский (фенноскандинавский) щит; водлозерский домен; уросозерская зеленокаменная структура; геология; метаморфизм; u-pb датирование
• Online Access: http://journals.krc.karelia.ru/index.php/precambrian/article/view/293

<p>The results of detailed study of the Urosozero greenstone structure (northwestern part of the Vodlozero domain) of the Fennoscandian Shield are presented. The composition and the U-Pb zircon age of the volcanic rocks were studied. The Urosozero structure is composed mainly of mafic-felsic volcanic rocks rather than the sediments. Mafic and ultramafic volcanics were obtained under high degree source melting followed by crustal contamination. Intermediate and acid volcanics vary from andesites to rhyolites and are similar in composition to the volcanics of the Shiloss and Lake Kamennoe greenstone structures. The methamorphism of dacites occurred at T = 400–610 °С and P &gt; 4 kbar. SIMS SHRIMP-II U-Pb dating of the dacite specimen was carried out on separate zircon grains at the Centre of Isotopic Research (VSEGEI, St. Petersburg). The ages received include 2875 ± 9 Ma as the time of volcanism and 2709 ± 8 Ma as the time of metamorphism. So, the volcanism of the Uros greenstone structure is synchronous with the volcanism of the northern Vodlozero domain.</p>