Xenotime-(Gd), a new Gd-dominant mineral of the xenotime group from the Zimná Voda REE-U-Au quartz vein, Prakovce, Western Carpathians, Slovakia

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00023272%3A_____%2F24%3A10136755" target="_blank" >RIV/00023272:_____/24:10136755 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.cambridge.org/core/journals/mineralogical-magazine/article/xenotimegd-a-new-gddominant-mineral-of-the-xenotime-group-from-the-zimna-voda-reeuau-quartz-vein-prakovce-western-carpathians-slovakia/BAE272E641CD070077D393E07047A620" target="_blank" >https://www.cambridge.org/core/journals/mineralogical-magazine/article/xenotimegd-a-new-gddominant-mineral-of-the-xenotime-group-from-the-zimna-voda-reeuau-quartz-vein-prakovce-western-carpathians-slovakia/BAE272E641CD070077D393E07047A620</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1180/mgm.2024.62" target="_blank" >10.1180/mgm.2024.62</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Xenotime-(Gd), a new Gd-dominant mineral of the xenotime group from the Zimná Voda REE-U-Au quartz vein, Prakovce, Western Carpathians, Slovakia

Popis výsledku v původním jazyce

Xenotime-(Gd), ideally GdPO4, is a new mineral of the xenotime group. It was discovered at the Zimná Voda REE-U-Au occurrence near Prakovce, Western Carpathians, Slovakia. It forms rare crystal domains (up to 20 microns, usually 10 microns in size) in Gd-rich xenotime-(Y) crystals (up to 100 microns in size), in association with monazite-group minerals, uraninite, fluorapatite and uranyl arsenates-phosphates. The hydrothermal REE-U-Au mineralisation occurs in a quartz-muscovite vein, hosted in Palaeozoic phyllites near exocontact with Permian granites. The density is 5.26 g/cm3, based on calculated average empirical formula and unit-cell parameters. The average chemical composition (n = 6) measured by electron microprobe is as follows (wt.%): P2O5 30.1, As2O5 0.5, SiO2 0.2, UO2 0.3, Y2O3 15.7, (La, Ce, Pr, Nd)2O3 0.5, Sm2O3 5.7, Eu2O3 1.4, Gd2O3 29.2, Tb2O3 3.9, Dy2O3 10.4, Ho2O3 0.4, (Er, Tm, Yb, Lu)2O3 2.1, (Ca, Fe, Pb, Mn, Ba)O 0.1, total 100.5. The corresponding empirical formula calculated on the basis of 4 oxygen atoms is: (Gd0.37Y0.32Dy0.13Sm0.08Tb0.05Eu0.02Er0.01Tm0.01Nd0.01)Σ1.01(P0.98As0.01Si0.01)O4. The empirical formula of the Gd-richest composition is: (Gd0.38Y0.31Dy0.13Sm0.08Tb0.05Eu0.02Er0.01Nd0.01Ho0.01)Σ1.01(P0.98As0.01Si0.01)O4. The ideal formula is GdPO4. The xenotime-type structure has been confirmed by micro-Raman spectroscopy and a Fast Fourier-Transform pattern using HRTEM. Xenotime-(Gd) is tetragonal, space group I41/amd, a = 6.9589(5), c = 6.0518(6) Å, V = 293.07(3) Å3 and Z = 4. The new mineral is named as an analogue of xenotime-(Y) and xenotime-(Yb) with Gd dominant among the REE. The middle REE enrichment of xenotime-(Gd) is shared with the associated monazite-(Gd) and Gd-rich hingganite-(Y). This exotic REE signature and precipitation of Gd-bearing minerals is a product of selective complexing and enrichment in MREE in low-temperature hydrothermal fluids by alteration of uraninite, brannerite and fluorapatite.

Název v anglickém jazyce

Xenotime-(Gd), a new Gd-dominant mineral of the xenotime group from the Zimná Voda REE-U-Au quartz vein, Prakovce, Western Carpathians, Slovakia

Popis výsledku anglicky

Xenotime-(Gd), ideally GdPO4, is a new mineral of the xenotime group. It was discovered at the Zimná Voda REE-U-Au occurrence near Prakovce, Western Carpathians, Slovakia. It forms rare crystal domains (up to 20 microns, usually 10 microns in size) in Gd-rich xenotime-(Y) crystals (up to 100 microns in size), in association with monazite-group minerals, uraninite, fluorapatite and uranyl arsenates-phosphates. The hydrothermal REE-U-Au mineralisation occurs in a quartz-muscovite vein, hosted in Palaeozoic phyllites near exocontact with Permian granites. The density is 5.26 g/cm3, based on calculated average empirical formula and unit-cell parameters. The average chemical composition (n = 6) measured by electron microprobe is as follows (wt.%): P2O5 30.1, As2O5 0.5, SiO2 0.2, UO2 0.3, Y2O3 15.7, (La, Ce, Pr, Nd)2O3 0.5, Sm2O3 5.7, Eu2O3 1.4, Gd2O3 29.2, Tb2O3 3.9, Dy2O3 10.4, Ho2O3 0.4, (Er, Tm, Yb, Lu)2O3 2.1, (Ca, Fe, Pb, Mn, Ba)O 0.1, total 100.5. The corresponding empirical formula calculated on the basis of 4 oxygen atoms is: (Gd0.37Y0.32Dy0.13Sm0.08Tb0.05Eu0.02Er0.01Tm0.01Nd0.01)Σ1.01(P0.98As0.01Si0.01)O4. The empirical formula of the Gd-richest composition is: (Gd0.38Y0.31Dy0.13Sm0.08Tb0.05Eu0.02Er0.01Nd0.01Ho0.01)Σ1.01(P0.98As0.01Si0.01)O4. The ideal formula is GdPO4. The xenotime-type structure has been confirmed by micro-Raman spectroscopy and a Fast Fourier-Transform pattern using HRTEM. Xenotime-(Gd) is tetragonal, space group I41/amd, a = 6.9589(5), c = 6.0518(6) Å, V = 293.07(3) Å3 and Z = 4. The new mineral is named as an analogue of xenotime-(Y) and xenotime-(Yb) with Gd dominant among the REE. The middle REE enrichment of xenotime-(Gd) is shared with the associated monazite-(Gd) and Gd-rich hingganite-(Y). This exotic REE signature and precipitation of Gd-bearing minerals is a product of selective complexing and enrichment in MREE in low-temperature hydrothermal fluids by alteration of uraninite, brannerite and fluorapatite.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10504 - Mineralogy

Projekt

—

Návaznosti

V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Mineralogical Magazine

ISSN

0026-461X

e-ISSN

—

Svazek periodika

88

Číslo periodika v rámci svazku

5

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

10

Strana od-do

613-622

Kód UT WoS článku

001357423000001

EID výsledku v databázi Scopus

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