Details
| Original language | English |
|---|---|
| Pages (from-to) | 51-60 |
| Number of pages | 10 |
| Journal | Contributions to Mineralogy and Petrology |
| Volume | 162 |
| Issue number | 1 |
| Publication status | Published - 27 Oct 2010 |
Abstract
Viscosity experiments were conducted with two flux-rich pegmatitic melts PEG0 and PEG2. The Li2O, F, B2O3 and P2O5 contents of these melts were 1.04, 4.06, 2.30 and 1.68 and 1.68, 5.46, 2.75 and 2.46 wt%, respectively. The water contents varied from dry to 9. 04 wt% H2O. The viscosity was determined in internally heated gas pressure vessels using the falling sphere method in the temperature range 873-1,373 K at 200 and 320 MPa pressure. At 1,073 K, the viscosity of water-rich (~9 wt% H2O) melts is in the range of 3-60 Pa s, depending on the melt composition. Extrapolations to lower temperature assuming an Arrhenian behavior indicate that highly fluxed pegmatite melts may reach viscosities of ~30 Pa s at 773 K. However, this value is a minimum estimation considering the strongly non-Arrhenian behavior of hydrous silicate melts. The experimentally determined melt viscosities are lower than the prediction of current models taking compositional parameters into account. Thus, these models need to be improved to predict accurately the viscosity of flux-rich water bearing melts. The data also indicate that Li influences significantly the melt viscosity. Decreasing the molar Al/(Na + K + Li) ratio results in a strong viscosity decrease, and highly fluxed melts with low Al/(Na + K + Li) ratios (~0. 8) have a rheological behavior which is very close to that of supercritical fluids.
Keywords
- Falling sphere, Pegmatite, Viscosity, Water
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geophysics
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
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In: Contributions to Mineralogy and Petrology, Vol. 162, No. 1, 27.10.2010, p. 51-60.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Viscosity of flux-rich pegmatitic melts
AU - Bartels, Alexander
AU - Vetere, Francesco
AU - Holtz, Francois
AU - Behrens, Harald
AU - Linnen, Robert L.
N1 - Funding Information: Acknowledgments This research has been supported by the German Science Foundation (DFG project Be 1720/24). We would like to thank O. Diedrich for preparing the samples and thin sections, Ullrich Kroll, Markus Köhler and Fabian Christ for the technical support as well as Dr. Lothar Borchers from the Hannover Medical School for the help in recording the X-ray images. Copyright: Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2010/10/27
Y1 - 2010/10/27
N2 - Viscosity experiments were conducted with two flux-rich pegmatitic melts PEG0 and PEG2. The Li2O, F, B2O3 and P2O5 contents of these melts were 1.04, 4.06, 2.30 and 1.68 and 1.68, 5.46, 2.75 and 2.46 wt%, respectively. The water contents varied from dry to 9. 04 wt% H2O. The viscosity was determined in internally heated gas pressure vessels using the falling sphere method in the temperature range 873-1,373 K at 200 and 320 MPa pressure. At 1,073 K, the viscosity of water-rich (~9 wt% H2O) melts is in the range of 3-60 Pa s, depending on the melt composition. Extrapolations to lower temperature assuming an Arrhenian behavior indicate that highly fluxed pegmatite melts may reach viscosities of ~30 Pa s at 773 K. However, this value is a minimum estimation considering the strongly non-Arrhenian behavior of hydrous silicate melts. The experimentally determined melt viscosities are lower than the prediction of current models taking compositional parameters into account. Thus, these models need to be improved to predict accurately the viscosity of flux-rich water bearing melts. The data also indicate that Li influences significantly the melt viscosity. Decreasing the molar Al/(Na + K + Li) ratio results in a strong viscosity decrease, and highly fluxed melts with low Al/(Na + K + Li) ratios (~0. 8) have a rheological behavior which is very close to that of supercritical fluids.
AB - Viscosity experiments were conducted with two flux-rich pegmatitic melts PEG0 and PEG2. The Li2O, F, B2O3 and P2O5 contents of these melts were 1.04, 4.06, 2.30 and 1.68 and 1.68, 5.46, 2.75 and 2.46 wt%, respectively. The water contents varied from dry to 9. 04 wt% H2O. The viscosity was determined in internally heated gas pressure vessels using the falling sphere method in the temperature range 873-1,373 K at 200 and 320 MPa pressure. At 1,073 K, the viscosity of water-rich (~9 wt% H2O) melts is in the range of 3-60 Pa s, depending on the melt composition. Extrapolations to lower temperature assuming an Arrhenian behavior indicate that highly fluxed pegmatite melts may reach viscosities of ~30 Pa s at 773 K. However, this value is a minimum estimation considering the strongly non-Arrhenian behavior of hydrous silicate melts. The experimentally determined melt viscosities are lower than the prediction of current models taking compositional parameters into account. Thus, these models need to be improved to predict accurately the viscosity of flux-rich water bearing melts. The data also indicate that Li influences significantly the melt viscosity. Decreasing the molar Al/(Na + K + Li) ratio results in a strong viscosity decrease, and highly fluxed melts with low Al/(Na + K + Li) ratios (~0. 8) have a rheological behavior which is very close to that of supercritical fluids.
KW - Falling sphere
KW - Pegmatite
KW - Viscosity
KW - Water
UR - http://www.scopus.com/inward/record.url?scp=79958082199&partnerID=8YFLogxK
U2 - 10.1007/s00410-010-0582-3
DO - 10.1007/s00410-010-0582-3
M3 - Article
AN - SCOPUS:79958082199
VL - 162
SP - 51
EP - 60
JO - Contributions to Mineralogy and Petrology
JF - Contributions to Mineralogy and Petrology
SN - 0010-7999
IS - 1
ER -