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Composition and structure of zircon from hydrothermal uranium occurrences of the Litsa ore area (Kola Region, Russia)

Citation

Kaulina, T and Lyalina, L and Kamenetsky, V and Il'chenko, V and Bocharov, V and Gannibal, M, Composition and structure of zircon from hydrothermal uranium occurrences of the Litsa ore area (Kola Region, Russia), Geosciences, 10, (8) Article 278. ISSN 2076-3263 (2020) [Refereed Article]


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Copyright Statement

Copyright: © 2020 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) license (https://creativecommons.org/licenses/by/4.0/).

DOI: doi:10.3390/geosciences10080278

Abstract

Zircon grains from various metagranitoids (plagio- and monzo-granites, gneisses, metasomatic rocks, and pegmatoid veins) from the Skal’noe and Dikoe sites of the Litsa uranium ore area (Kola Region, Russia) were studied in order to reconstruct the sequence and timing of events in the area and to observe effects of hydrothermal process related to uranium mineralization on structure and composition of zircon. Individual zircon grains were studied by means of laser ablation inductively coupled plasma mass spectrometry (LA–ICPMS), ion microprobe and Raman spectroscopy. Isotopic LA–ICPMS data for the Skal’noye and Dikoe ore occurrences suggest the following age sequence of events in the area: intrusion of plagiogranites - 2829 ± 12 Ma, formation of magmatic protolith of gneisses - 2781 ± 17 Ma, metamorphism of plagiogranites - 2636 ± 34 Ma; intrusion of monzogranites and pegmatoid veins - 2549–2526 Ma, hydrothermal event with uranium input - 2276 ± 21 Ma, last metamorphism of plagio- and monzo-granites - 1892–1696 Ma. Ore-bearing rocks in the area are pegmatoid veins and quartz–feldspar metasomatites which contain uraninite. During a 2.3 Ga hydrothermal process, newly formed zircon rims grew simultaneously with the precipitation of uraninite in the veins and metasomatites. These rims are characterized by high U and rare earth elements (REE) contents (up to 6560 and 8760 ppm, respectively), dark cathodoluminescence, low Th-U ratios (0.1–0.007) and a flat LREE-enriched pattern, in some cases inherited from minerals, dissolved during a hydrothermal event (magmatic plagioclase and probably monazite). Hydrothermal zircon rims grew with partial dissolution of the magmatic zircon, as evidenced by the rounded and curved shapes of zircon cores. The degree of alteration caused by hydrothermal events depends on the uranium content in the pre-existing zircon. The effects of zircon alteration and newly formed zircon composition reflect the redistribution of uranium in rocks.

Item Details

Item Type:Refereed Article
Keywords:zircon, REE, Raman spectroscopy, U mineralization, hydrothermal processes, Kola region
Research Division:Earth Sciences
Research Group:Geology
Research Field:Geochronology
Objective Division:Energy
Objective Group:Energy exploration
Objective Field:Uranium exploration
UTAS Author:Kamenetsky, V (Professor Vadim Kamenetsky)
ID Code:143713
Year Published:2020
Web of Science® Times Cited:1
Deposited By:CODES ARC
Deposited On:2021-03-30
Last Modified:2021-09-29
Downloads:2 View Download Statistics

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