Details
| Original language | English |
|---|---|
| Pages (from-to) | 184-198 |
| Number of pages | 15 |
| Journal | Chemical Geology |
| Volume | 346 |
| Early online date | 18 Sept 2012 |
| Publication status | Published - 7 May 2013 |
Abstract
The individual influences of F, B and P on viscosity of hydrous pegmatite forming melts have been determined experimentally. A starting glass composition (68.01wt.% SiO2, 20.14wt.% Al2O3, 7.73wt.% Na2O and 4.26wt.% K2O, Al/(Na+K)=1.16) was doped with different amounts of F (up to 4.81wt.%), B2O3 (0.93wt.%) and P2O5 (up to 2.98wt.%). The viscosity of melts containing 0.08 to 6.15wt.% H2O was determined in the high and low viscosity range using the micropenetration technique and the falling sphere method, respectively. Falling sphere experiments were carried out at 200 to 650MPa and 1173 to 1530K. Micropenetration measurements were performed in the temperature range of 586 to 1124K at ambient pressure.For all compositions a large decrease of viscosity upon hydration was observed, consistent with previous findings. The results also confirm that the viscosity decreases with the addition of F at all investigated temperatures. This decrease is more pronounced at low temperature and at low water content. According to our data, P and B do not play a major role on viscous flow in water-rich systems. However, the depolymerizing effect of H2O and F is not sufficient to explain very low viscosities of complex highly fractionated melts containing H2O, F, B, P and Li (Bartels et al., 2011). Thus, although we confirm that F is clearly a fluxing agent, Li must play a crucial role in lowering the viscosity of natural pegmatite forming melts and combined effects between different constituents need to be taken under consideration.
Keywords
- Boron, Falling sphere, Fluorine, Micropenetration, Pegmatite, Viscosity
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geology
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
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In: Chemical Geology, Vol. 346, 07.05.2013, p. 184-198.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - The effect of fluorine, boron and phosphorus on the viscosity of pegmatite forming melts
AU - Bartels, Alexander
AU - Behrens, Harald
AU - Holtz, Francois
AU - Schmidt, Burkhard C.
AU - Fechtelkord, Michael
AU - Knipping, Jaayke
AU - Crede, Lars
AU - Baasner, Amrei
AU - Pukallus, Nina
N1 - Funding Information: This research has been supported by the German Science Foundation (DFG project Be 1720/24-1 and SCHM 1622/5-1). Jaayke Knipping, Lars Crede, Amrei Baasner and Nina Pukallus participated to this study in the frame of their Bachelor theses. We would also like to thank two anonymous reviewers for their helpful comments. Copyright: Copyright 2013 Elsevier B.V., All rights reserved.
PY - 2013/5/7
Y1 - 2013/5/7
N2 - The individual influences of F, B and P on viscosity of hydrous pegmatite forming melts have been determined experimentally. A starting glass composition (68.01wt.% SiO2, 20.14wt.% Al2O3, 7.73wt.% Na2O and 4.26wt.% K2O, Al/(Na+K)=1.16) was doped with different amounts of F (up to 4.81wt.%), B2O3 (0.93wt.%) and P2O5 (up to 2.98wt.%). The viscosity of melts containing 0.08 to 6.15wt.% H2O was determined in the high and low viscosity range using the micropenetration technique and the falling sphere method, respectively. Falling sphere experiments were carried out at 200 to 650MPa and 1173 to 1530K. Micropenetration measurements were performed in the temperature range of 586 to 1124K at ambient pressure.For all compositions a large decrease of viscosity upon hydration was observed, consistent with previous findings. The results also confirm that the viscosity decreases with the addition of F at all investigated temperatures. This decrease is more pronounced at low temperature and at low water content. According to our data, P and B do not play a major role on viscous flow in water-rich systems. However, the depolymerizing effect of H2O and F is not sufficient to explain very low viscosities of complex highly fractionated melts containing H2O, F, B, P and Li (Bartels et al., 2011). Thus, although we confirm that F is clearly a fluxing agent, Li must play a crucial role in lowering the viscosity of natural pegmatite forming melts and combined effects between different constituents need to be taken under consideration.
AB - The individual influences of F, B and P on viscosity of hydrous pegmatite forming melts have been determined experimentally. A starting glass composition (68.01wt.% SiO2, 20.14wt.% Al2O3, 7.73wt.% Na2O and 4.26wt.% K2O, Al/(Na+K)=1.16) was doped with different amounts of F (up to 4.81wt.%), B2O3 (0.93wt.%) and P2O5 (up to 2.98wt.%). The viscosity of melts containing 0.08 to 6.15wt.% H2O was determined in the high and low viscosity range using the micropenetration technique and the falling sphere method, respectively. Falling sphere experiments were carried out at 200 to 650MPa and 1173 to 1530K. Micropenetration measurements were performed in the temperature range of 586 to 1124K at ambient pressure.For all compositions a large decrease of viscosity upon hydration was observed, consistent with previous findings. The results also confirm that the viscosity decreases with the addition of F at all investigated temperatures. This decrease is more pronounced at low temperature and at low water content. According to our data, P and B do not play a major role on viscous flow in water-rich systems. However, the depolymerizing effect of H2O and F is not sufficient to explain very low viscosities of complex highly fractionated melts containing H2O, F, B, P and Li (Bartels et al., 2011). Thus, although we confirm that F is clearly a fluxing agent, Li must play a crucial role in lowering the viscosity of natural pegmatite forming melts and combined effects between different constituents need to be taken under consideration.
KW - Boron
KW - Falling sphere
KW - Fluorine
KW - Micropenetration
KW - Pegmatite
KW - Viscosity
UR - http://www.scopus.com/inward/record.url?scp=84876962398&partnerID=8YFLogxK
U2 - 10.1016/j.chemgeo.2012.09.024
DO - 10.1016/j.chemgeo.2012.09.024
M3 - Article
AN - SCOPUS:84876962398
VL - 346
SP - 184
EP - 198
JO - Chemical Geology
JF - Chemical Geology
SN - 0009-2541
ER -