First Age and Geochemical Data on Zircon from Riebeckite Granites of the Verkhnee Espe Rare Earth–Rare Metal Deposit, East Kazakhstan

• Published in: Geochemistry international 2022, Vol.60 (1), p.1-15
• Main Authors: Levashova, E. V., Skublov, S. G., Oitseva, T. A., Dyachkov, B. A., Li, X.-H., Li, Q.-L., Shatova, N. V., Shatov, V. V.
• Format: Article
• Language: English
• Subjects: Age; Asbestos; Crystallization; Earth; Earth and Environmental Science; Earth Sciences; Geochemistry; Granite; Heavy metals; Heterogeneous structure; Isotopes; Massifs; Melts; Radiometric dating; Rare earth elements; Rare earth metals; Trace elements; Yttrium; Zircon
• ISSN: 0016-7029; 1556-1968
• DOI: 10.1134/S0016702922010086

This paper is dedicated to the isotope-geochemical study of zircon from riebeckite granites of the Verkhnee Espe rare earth-rare metal deposit and the specification of its U–Pb age. Zircon from the Verkhnee Espe massif is peculiar in the high content of non-formula elements (up to 43000 ppm REE, up to 22000 Y, and others) and demonstrates a clearly expressed heterogeneous structure. The central and rim zones of the zircon show a “magmatic” rare-earth element (REE) distribution. The intermediate zones are characterized by a flattening of the REE patterns and an anomalous enrichment in REE, Y, Nb, and Ca. This compositional feature of the zircon may be caused by impact of fluid-saturated granite melts enriched in incompatible trace elements. The δ 18 О values in the zircon are 5.83–7.16‰, which generally corresponds to zircon formed from granitoid melts. The age of zircon from the Verkhnee Espe rare earth–rare metal deposit is 283 ± 3 Ma, which indicates that there is no significant age gap between granite crystallization, on the one hand, and metasomatic processes and ore generation, on the other.