Middle Devonian Age of Metamorphism of Garnet Amphibolite at the Sole of the Kempirsai Ophiolite Allochthon (Southern Urals): Results of U–Th–Pb (SIMS) Dating

• Published in: Doklady earth sciences Vol. 501; no. 2; pp. 1009 - 1014
• Main Authors: Ryazantsev, A. V., Skoblenko, A. V., Golionko, B. G., Artyomova, O. A.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-12-2021; Springer Nature B.V
• Subjects: Age; Aluminum oxide; Amphibolite facies; Amphibolites; Corundum; Devonian; Earth and Environmental Science; Earth Sciences; Garnet; Geology; Lead isotopes; Magma; Metamorphism; Obduction; Palaeozoic; Paleozoic; Pyroxenes; Sedimentary facies; Devonian; U–Pb zircon dating; ophiolite; Kempirsai allochthon; garnet amphibolite; metamorphic sole; obduction; Southern Urals
• ISSN: 1028-334X; 1531-8354
• DOI: 10.1134/S1028334X21120096

Metagabbroid garnet amphibolite formed after high-pressure granulite with an estimated
P–T
peak of 12–16 kbar at 700–790°C occurs at the sole of the Kempirsai ophiolite allochthon (Southern Urals). Garnet amphibolite includes high-Fe varieties with the assemblages of garnet and relics of pyroxene, as well as high-alumina rocks composed of garnet, pyroxene, corundum, and sapphirine. The Ediacaran and Early–Middle Palaeozoic sequences underlying the allochthon were metamorphosed under the conditions of amphibolite facies. Our studies were aimed at estimation of the peak metamorphic age of garnet amphibolite. The mean
206
Pb/
238
U (SIMS, SHRIMP II) age obtained for the zircons from garnet amphibolite is 392 ± 4 Ma. The estimated age characterizes the timing of metamorphism related to mantle magmatism accompanying obduction.