The oldest volcanic glass in the early paleoproterozoic boninite-type lavas, Karelian craton: Results of instrumental investigations

• Main Authors: Sharkov E.V., Trubkin N.V., Krasivskaya I.S., Bogatikov O.A., Mokhov A.V., Zolotykh E.B., Ladygin V.M., Chistyakov A.V., Evseeva K.A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: chemical composition; geochemistry; lava; Proterozoic; volcanic glass; Russian Federation; karelian
• Online Access: https://openrepository.ru/article?id=256970

Since Early Precambrian volcanic rocks are typically strongly altered by superimposed processes, they retain primary composition and texture only in exceptional cases. Such a case is observed in the Early Paleoproterozoic volcanic rocks of the Vetrenyi Belt Formation of the synonymous riftogenic structure in southeastern Karelia, where volcanic glass is locally preserved [1-3]. The Sm-Nd, Re-Os, and U-Pb (zircon) ages of volcanic rocks of this formation range from 2.5 Ga in the lower parts to 2.41 Ga in the upper parts of the sequence [1-3]. Zolotykh and Ladygin [4, 5] also confirmed the presence of volcanic glass in these rocks. During short-term field works in 2000, we collected additional samples in the southeastern termination of the graben-shaped Vetrenyi Belt, where the least altered rocks were preserved. The samples were mainly treated at the Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry.