2019
A Ta,Ti-rich oxide mineral assemblage from the Nancy beryl-columbite-phosphate granitic pegmatite, San Luis, Argentina
GALLISKI, M.A., M.F. MARQUEZ-ZAVALIA, Radek ŠKODA, Milan NOVÁK, Renata ČOPJAKOVÁ et. al.Základní údaje
Originální název
A Ta,Ti-rich oxide mineral assemblage from the Nancy beryl-columbite-phosphate granitic pegmatite, San Luis, Argentina
Autoři
GALLISKI, M.A. (garant), M.F. MARQUEZ-ZAVALIA, Radek ŠKODA (203 Česká republika, domácí), Milan NOVÁK (203 Česká republika, domácí), Renata ČOPJAKOVÁ (203 Česká republika, domácí) a D.S. PAGANO
Vydání
Mineralogy and Petrology, WIEN, Springer Wien, 2019, 0930-0708
Další údaje
Jazyk
angličtina
Typ výsledku
Článek v odborném periodiku
Obor
10504 Mineralogy
Stát vydavatele
Rakousko
Utajení
není předmětem státního či obchodního tajemství
Odkazy
Impakt faktor
Impact factor: 1.461
Kód RIV
RIV/00216224:14310/19:00113463
Organizační jednotka
Přírodovědecká fakulta
UT WoS
000485902500008
Klíčová slova anglicky
Tantalite-(Mn); Tantalian rutile; Wodginite-group minerals; Hydroxycalciomicrolite; Rare-element granitic pegmatite; Sierras Pampeanas; Argentina
Štítky
Změněno: 1. 4. 2020 14:44, Mgr. Marie Šípková, DiS.
Anotace
V originále
An assemblage of tantalite-(Mn), tantalian rutile, tapiolite-(Fe), titanowodginite, ferrotitanowodginite, and hydroxycalciomicrolite occurs in the Nancy granitic pegmatite, San Luis range, Argentina. The Nancy beryl-type, beryl-columbite-phosphate subtype of LCT (Li-Cs-Ta) rare-element pegmatite was emplaced in the Paleozoic Conlara pegmatitic field. The assemblage occurs at the core margin of the pegmatite, forming an irregularly shaped, 18 by 6 cm nodule. The chemical composition of tantalite-(Mn) shows median Ta [= (Ta/(Ta + Nb) apfu (atoms per formula unit)] and Mn [= (Mn/(Mn + Fe-T) apfu] values of 0.57 and 0.64, respectively; Ti, U and Zr show maximum and [median] contents of: 3.37 [1.25] wt.% TiO2, 0.58 [0.24] wt.% UO2, and 0.72 [0.50] wt.% ZrO2. The unit-cell parameters indicate a moderately ordered structure. Tantalian rutile occurs as anhedral grains replacing tantalite-(Mn), associated with hydroxycalciomicrolite. Its chemical composition shows moderate to high Ti contents, with a maximum and [median] of 64.77 [38.67] wt.% TiO2. The proportion of Ta is very high, with 49.67 [39.59] wt.% Ta2O5. Tapiolite-(Fe), with 82.49 [81.86] wt.% Ta2O5, 2.51 [2.33] wt.% Nb2O5, 0.94 [0.79] wt.% TiO2, and 13.31 [13.18] wt.% FeO, has uniform Ta and Mn values, 0.95 and 0.09, respectively. Titanowodginite shows Ta values ranging from 0.82 to 0.88, whereas in ferrotitanowodginite it ranges from 0.88 to 0.94. The Mn value is similar in titanowodginite (0.51-0.64), and decreases in the ferrotitanowodginite (0.04 to 0.41). These minerals form a replacement sequence of tantalite-(Mn). Hydroxycalciomicrolite occurs in two generations: I and II. The dominant A cation is Ca, with a median value of 14.39 wt.% CaO. The MnO content, with a median of 1.16 wt.% MnO, is relatively constant. The amount of UO2 is usually below 3 wt.%, but locally attains 6.9 wt.%, and exceptionally 43.6 wt.%, in irregular rims that show a low analytical total, giving compositions that depart from the expected stoichiometry; it is clearly a subsolidus phase. In the more plausible explanation for the evolution of this assemblage, the magmatic crystallization of tantalite-(Mn) was followed during the early subsolidus stage by its partial replacement by tantalian rutile + tapiolite-(Fe) + titanowodginite + ferrotitanowodginte, associated with hydroxycalciomicrolite I, and later, by hydroxycalciomicrolite II produced by the influx of a late Fe-Ti-Ca-bearing fluid phase likely entering the pegmatite from the wall rocks.
Návaznosti
| 7AMB14AR006, projekt VaV |
|