The importance of cation–cation repulsion in the zircon–reidite phase transition and radiation-damaged zircon

Tokuda, Makoto; Yoshiasa, Akira; Kojitani, Hiroshi; Hashimoto, Saki; Uehara, Satoshi; Mashimo, Tsutomu; Tobase, Tsubasa; Akaogi, Masaki

doi:10.1180/mgm.2019.27

Cited by 7 publications

(6 citation statements)

References 24 publications

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“…Some zircons show inclusions of apatite or quartz. The damage densities calculated from the measured 3 using the calibration of Váczi and Nasdala (2017) range from ∼ 22 to ∼ 200 × 10 16 α/g; they can thus be classified as slightly to highly damaged. We discarded grains with cracks that might fall apart upon heating or cooling.…”

Section: Zircon Samplesmentioning

confidence: 99%

“…The α disintegration of U and Th creates lattice disorder by the impact of α particles and the recoil of daughter nuclei. The zircon Raman spectrum is sensitive to lattice damage: the downshift and broadening of the Raman bands provide a quantitative measure for the radiation damage (Nasdala et al, 1995(Nasdala et al, , 1998(Nasdala et al, , 2001Palenik et al, 2003;Váczi and Nasdala, 2017).…”

Section: Introductionmentioning

confidence: 99%

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The closure temperature(s) of zircon Raman dating

et al. 2021

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Abstract. Zircon Raman dating based on irradiation damage is a debated concept but not an established geo-/thermochronological method. One issue is the temperature range of radiation-damage annealing over geological timescales. We conducted isochronal and isothermal annealing experiments on radiation-damaged zircons between 500 and 1000 ∘C for durations between 10 min and 5 d to describe the annealing kinetics. We measured the widths (Γ) and positions (ω) of the ν1(SiO4), ν2(SiO4), and ν3(SiO4) internal Raman bands, and the external rotation Raman band at ∼974, 438, 1008, and 356 cm−1 after each annealing step. We fitted a Johnson–Mehl–Avrami–Kolmogorov and a distributed activation energy model to the fractional annealing data, calculated from the widths of the ν2(SiO4), ν3(SiO4), and external rotation bands. From the kinetic models, we determined closure temperatures Tc for damage accumulation for each Raman band. Tc ranges from 330 to 370 ∘C for the internal ν2(SiO4) and ν3(SiO4) bands; the external rotation band is more sensitive to thermal annealing (Tc∼260 to 310 ∘C). Our estimates are in general agreement with previous ones, but more geological evidence is needed to validate the results. The Tc difference for the different Raman bands offers the prospect of a multi-closure-temperature zircon Raman thermochronometer.

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Section: Zircon Samplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The closure temperature(s) of zircon Raman dating

et al. 2021

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“…This phenomenon may be explained by the extensive damage around the A-site occupied by Th. The increased displacement parameter due to radioactive decay damage can also be observed for zircon in ZrSiO 4 (Tokuda et al, 2019).…”

Section: Displacement Parameter Of Each Atom In Ce-and Nbperovskitementioning

confidence: 75%

XANES analyses on minor elements and X–ray single crystal structure analyses of Ce– and Nb–perovskite

Kitahara

Yoshiasa

Tokuda

et al. 2021

Journal of Mineralogical and Petrological Sciences

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Structural analysis of Ce-and Nb-perovskites containing Fe, Zr, Nb, and rare earth elements (REEs) in CaTiO 3 perovskite was performed using single-crystal X-ray diffraction and X-ray absorption near-edge structure (XANES) analyses. Based on chemical analysis results, XANES measurements and the site-occupation of elements at A-and B-sites showed the chemical formula: (Ca 2+ 0.817 REE 3+ 0.087 Na + 0.081 Sr 2+ 0.005 Th 4+ 0.003 ) 1.998+ 0.993 (Ti 4+ 0.941 Nb 5+ 0.017 Fe 3+ 0.013 V 5+ 0.010 Fe 2+ 0.007 Sc 3+ 0.006 Zn 2+ 0.005 Al 3+ 0.002 Ge 4+ 0.001 W 6+ 0.001 ) 3.996+ 1.003 O 3 for Ce-perovskite and (Ca 2+ 0.937 Ce 3+ 0.021 Na + 0.020 La 3+ 0.015 Sr 2+ 0.003 ) 2.008+ 0.996 (Ti 4+ 0.730 Nb 5+ 0.122 Fe 3+ 0.108 Al 3+ 0.020 Zr 4+ 0.009 V 5+ 0.008 ) 3.990+ 0.997 O 3 for Nb-perovskite.In Ce-and Nbperovskites, the total charges at the A-and B-sites achieved near-ideal divalent and tetravalent states such as Ca 2+ Ti 4+ O 3 , respectively, due to complex elemental substitutions. Local distortions around Ti in the perovskite solid solutions were greater, and the pre-edge features of the Ti atoms in Ce-and Nb-perovskites were different from those in pure CaTiO 3 . The valence states and local structures of Fe in Ce-and Nb-perovskites were significantly different. The existence of divalent Fe 2+ at the B-site in Ce-perovskite was confirmed. It is presumed that the displacement ellipsoids of all atoms and local irregularities in Ce-perovskite increase owing to the radiative decay of the actinoid element Th. We reconfirmed that the composition and three-dimensional structure of perovskite-type structures were flexible and caused various electrical, structural changes.

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“…In contrast, ν2(SiO4) is a bending mode, depending on the angle between the Si-O bonds in the SiO4 tetrahedron (Geisler, 2002). The O-Si-O angle is related to the ratio of the unit cell parameters a and c (Tokuda et al, 2019). Figure 6 plots c vs. a for the XRD data for the annealing experiments of Colombo and Chrosch (1998a) and Geisler et al (2001).…”

Section: Changes In Band Position and Widthmentioning

confidence: 99%

“…Due to damage 6 accumulation, c increases more than a (Salje et al, 1999;Zhang et al, 2000b). The increased ratio c/a reduces the O-Si-O angle between the oxygen atoms shared by Si and Zr (Tokuda et al, 2019), shifting the ν2(SiO4) Raman band to lower wavenumbers. During stage I annealing, the unit cell shrinks anisotropically, reducing a more than c, causing a further increase of c/a and lowering of the O-Si-O angle.…”

Section: Changes In Band Position and Widthmentioning

confidence: 99%

The closure temperature(s) of zircon Raman dating

Härtel¹,

Jonckheere²,

Wauschkuhn³

et al. 2020

Preprint

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Abstract. We conducted isochronal and isothermal annealing experiments on radiation-damaged zircons between 500 and 1000 °C for durations between ten minutes and five days. We measured the widths (Γ) and positions (ω) of the internal ν1(SiO4), ν2(SiO4), ν3(SiO4), and external rotation Raman bands at ~ 974, 438, 1008, and 356 cm−1. We fitted a Johnson-Mehl-Avrami-Kolmogorov and a distributed activation energy model to the fractional annealing data, calculated from the widths of the ν2(SiO4), ν3(SiO4), and external rotation bands. From the kinetic models, we determined closure temperatures Tc for damage accumulation for each Raman band. Tc range from 330 to 370 °C for the internal ν2(SiO4) and ν3(SiO4) bands; the external rotation band is more sensitive to thermal annealing (Tc ~ 260 to 310 °C). Our estimates are in general agreement with previous ones, but more geological evidence is needed to validate the results. The Tc difference for the different Raman bands offers the prospect of a multi-closure-temperature zircon Raman thermochronometer.

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The importance of cation–cation repulsion in the zircon–reidite phase transition and radiation-damaged zircon

Cited by 7 publications

References 24 publications

The closure temperature(s) of zircon Raman dating

The closure temperature(s) of zircon Raman dating

XANES analyses on minor elements and X–ray single crystal structure analyses of Ce– and Nb–perovskite

The closure temperature(s) of zircon Raman dating

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