Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 537-544 |
| Seitenumfang | 8 |
| Fachzeitschrift | American Mineralogist |
| Jahrgang | 95 |
| Ausgabenummer | 4 |
| Publikationsstatus | Veröffentlicht - 1 Apr. 2010 |
Abstract
Solubility experiments of MnNb2O6 and MnTa 2O6 were conducted in two nominally dry to water-saturated pegmatitic melts with different amounts of Li, F, P, and B at 700 to 1000 °C and 200 MPa to determine the maximum concentrations of Nb and Ta in pegmatitic melts. The Li2O, F, B2O3, and P 2O5 contents in the melts were 1.16, 2.99, 1.78, and 1.55 wt% for melt composition PEG1 and 1.68, 5.46, 2.75, and 2.75 wt% for melt composition PEG2 and the resulting Al/(Na+K+Li) ratio for both melts is 0.92. The experimental data show that the solubility product of manganocolumbite increases by a factor of three upon increasing the water concentration from 0 to 4 wt%. Considering that pegmatitic melts at pressures above 50 to 100 MPa are hydrous (>4 wt% H2O), the increase in solubility by this magnitude, over the stated range of water concentration, is not significant for pegmatites. The data also point out that the solubility of MnNb 2O6 and MnTa2O6 is strongly temperature dependent, increasing by a factor of 50 for manganocolumbite and 15-20 for manganotantalite from 700 to 1000 °C under water-saturated conditions. The solubility also increases with increasing content of fluxing elements like Li, F, B, and P. In the pegmatite melt containing the highest amount of fluxing elements, the maximum concentrations of Ta and Nb are higher by nearly one order of magnitude when compared to a subaluminous rhyolitic melt.
ASJC Scopus Sachgebiete
- Erdkunde und Planetologie (insg.)
- Geophysik
- Erdkunde und Planetologie (insg.)
- Geochemie und Petrologie
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in: American Mineralogist, Jahrgang 95, Nr. 4, 01.04.2010, S. 537-544.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Solubility of manganotantalite and manganocolumbite in pegmatitic melts
AU - Bartels, Alexander
AU - Holtz, Francois
AU - Linnen, Robert L.
N1 - Copyright: Copyright 2010 Elsevier B.V., All rights reserved.
PY - 2010/4/1
Y1 - 2010/4/1
N2 - Solubility experiments of MnNb2O6 and MnTa 2O6 were conducted in two nominally dry to water-saturated pegmatitic melts with different amounts of Li, F, P, and B at 700 to 1000 °C and 200 MPa to determine the maximum concentrations of Nb and Ta in pegmatitic melts. The Li2O, F, B2O3, and P 2O5 contents in the melts were 1.16, 2.99, 1.78, and 1.55 wt% for melt composition PEG1 and 1.68, 5.46, 2.75, and 2.75 wt% for melt composition PEG2 and the resulting Al/(Na+K+Li) ratio for both melts is 0.92. The experimental data show that the solubility product of manganocolumbite increases by a factor of three upon increasing the water concentration from 0 to 4 wt%. Considering that pegmatitic melts at pressures above 50 to 100 MPa are hydrous (>4 wt% H2O), the increase in solubility by this magnitude, over the stated range of water concentration, is not significant for pegmatites. The data also point out that the solubility of MnNb 2O6 and MnTa2O6 is strongly temperature dependent, increasing by a factor of 50 for manganocolumbite and 15-20 for manganotantalite from 700 to 1000 °C under water-saturated conditions. The solubility also increases with increasing content of fluxing elements like Li, F, B, and P. In the pegmatite melt containing the highest amount of fluxing elements, the maximum concentrations of Ta and Nb are higher by nearly one order of magnitude when compared to a subaluminous rhyolitic melt.
AB - Solubility experiments of MnNb2O6 and MnTa 2O6 were conducted in two nominally dry to water-saturated pegmatitic melts with different amounts of Li, F, P, and B at 700 to 1000 °C and 200 MPa to determine the maximum concentrations of Nb and Ta in pegmatitic melts. The Li2O, F, B2O3, and P 2O5 contents in the melts were 1.16, 2.99, 1.78, and 1.55 wt% for melt composition PEG1 and 1.68, 5.46, 2.75, and 2.75 wt% for melt composition PEG2 and the resulting Al/(Na+K+Li) ratio for both melts is 0.92. The experimental data show that the solubility product of manganocolumbite increases by a factor of three upon increasing the water concentration from 0 to 4 wt%. Considering that pegmatitic melts at pressures above 50 to 100 MPa are hydrous (>4 wt% H2O), the increase in solubility by this magnitude, over the stated range of water concentration, is not significant for pegmatites. The data also point out that the solubility of MnNb 2O6 and MnTa2O6 is strongly temperature dependent, increasing by a factor of 50 for manganocolumbite and 15-20 for manganotantalite from 700 to 1000 °C under water-saturated conditions. The solubility also increases with increasing content of fluxing elements like Li, F, B, and P. In the pegmatite melt containing the highest amount of fluxing elements, the maximum concentrations of Ta and Nb are higher by nearly one order of magnitude when compared to a subaluminous rhyolitic melt.
KW - Columbite, tantalite
KW - Pegmatitic melt
KW - Solubility
KW - Volatiles
UR - http://www.scopus.com/inward/record.url?scp=77950888842&partnerID=8YFLogxK
U2 - 10.2138/am.2010.3157
DO - 10.2138/am.2010.3157
M3 - Article
AN - SCOPUS:77950888842
VL - 95
SP - 537
EP - 544
JO - American Mineralogist
JF - American Mineralogist
SN - 0003-004X
IS - 4
ER -