OH species, U ions, and CO/CO2 in thermally annealed metamict zircon (ZrSiO4)

Zhang, M. and Salje, E. K. H. and Ewing, R. C. (2010) OH species, U ions, and CO/CO2 in thermally annealed metamict zircon (ZrSiO4). American Mineralogist, 95. pp. 1717-1724. DOI 10.2138/am.2010.3567

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Official URL: http://dx.doi.org/10.2138/am.2010.3567

Abstract

Metamict zircon crystals have been thermally annealed between 500 and 1800 K and analyzed using infrared and optical spectroscopy in the spectral region of 1400–7000 cm–1. Recrystallization and dehydroxylation via complex proton/OH diffusion, redistribution, and incorporations of additional hydrogen-related species within the crystal structure of zircon occur at temperatures above 700 K in partially metamict zircon and above 1200 K in heavily amorphized material. Thermally induced changes in O-H stretching spectra are different between E || c and E ⊥ c in weakly metamict zircon. The O-H stretching band near 3342 cm–1 (with E ⊥ c) in an untreated sample shifts to 3277 cm–1 at 1200 K, where the frequency of O-H stretching bands with E || c increases. Conversions of hydrogen-related species were observed and extra OH bands were found at temperatures between 1200 and 1600 K. A dramatic change of OH spectra was recorded between 1600 and 1800 K in partially metamict crystals, resulting in additional absorption features (near 3098 and 2998 cm–1 along E ⊥ c). U4+ and U5+ related spectra are also affected by high-temperature annealing. For highly metamict zircon, the U4+ band near 4830 cm–1 shows an increase in intensity above 1200 K. Additional IR bands at 2146 and 2344 cm–1 appear in the spectra of metamict zircon annealed at high temperatures. Their frequencies are consistent with stretching vibrations of CO and CO2.

Item Type: Article
Uncontrolled Keywords: 2010AREP; IA61;
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: American Mineralogist
Volume: 95
Page Range: pp. 1717-1724
Identification Number: 10.2138/am.2010.3567
Depositing User: Sarah Humbert
Date Deposited: 14 Nov 2010 01:07
Last Modified: 23 Jul 2013 10:00
URI: http://eprints.esc.cam.ac.uk/id/eprint/1965

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