Details
| Original language | English |
|---|---|
| Pages (from-to) | 1-11 |
| Number of pages | 11 |
| Journal | Chemical Geology |
| Volume | 410 |
| Early online date | 31 May 2015 |
| Publication status | Published - 2 Sept 2015 |
Abstract
Viscosity experiments were conducted to investigate the effect of Li2O on the viscosity of pegmatite forming melts and the possible difference to K2O. The individual effects of Li2O and K2O on melt viscosity were investigated by adding the same molar proportion of both components to a starting composition representing natural pegmatite forming melts. The viscosity experiments on hydrous melts (~1 to ~6wt.% H2O) were carried out in the low temperature range at ambient pressure using the micropenetration technique and in the high temperature range at 200-300MPa pressure using the falling sphere method.The addition of Li2O and K2O results in a decrease of melt viscosity and, on a molar basis, the effect of Li2O is comparable to that of K2O. Viscosity-related properties such as activation energy of viscous flow, melt fragility and glass transition temperature are affected in a similar way by both alkali oxides. The observed effects of alkalis on the viscosity of melt are smaller when compared to an equal molar amount of OH- groups at low water content but become equal with increasing water content. Finally, it is shown that the low viscosity of pegmatite forming melts can only be explained by the combined effects of H2O, F and of non-charge balancing alkalis.
Keywords
- Alkalis, Falling sphere, Lithium, 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. 410, 02.09.2015, p. 1-11.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - The effect of lithium on the viscosity of pegmatite forming liquids
AU - Bartels, Alexander
AU - Behrens, Harald
AU - Holtz, Francois
AU - Schmidt, Burkhard C.
N1 - Publisher Copyright: © 2015 Elsevier B.V.. Copyright: Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2015/9/2
Y1 - 2015/9/2
N2 - Viscosity experiments were conducted to investigate the effect of Li2O on the viscosity of pegmatite forming melts and the possible difference to K2O. The individual effects of Li2O and K2O on melt viscosity were investigated by adding the same molar proportion of both components to a starting composition representing natural pegmatite forming melts. The viscosity experiments on hydrous melts (~1 to ~6wt.% H2O) were carried out in the low temperature range at ambient pressure using the micropenetration technique and in the high temperature range at 200-300MPa pressure using the falling sphere method.The addition of Li2O and K2O results in a decrease of melt viscosity and, on a molar basis, the effect of Li2O is comparable to that of K2O. Viscosity-related properties such as activation energy of viscous flow, melt fragility and glass transition temperature are affected in a similar way by both alkali oxides. The observed effects of alkalis on the viscosity of melt are smaller when compared to an equal molar amount of OH- groups at low water content but become equal with increasing water content. Finally, it is shown that the low viscosity of pegmatite forming melts can only be explained by the combined effects of H2O, F and of non-charge balancing alkalis.
AB - Viscosity experiments were conducted to investigate the effect of Li2O on the viscosity of pegmatite forming melts and the possible difference to K2O. The individual effects of Li2O and K2O on melt viscosity were investigated by adding the same molar proportion of both components to a starting composition representing natural pegmatite forming melts. The viscosity experiments on hydrous melts (~1 to ~6wt.% H2O) were carried out in the low temperature range at ambient pressure using the micropenetration technique and in the high temperature range at 200-300MPa pressure using the falling sphere method.The addition of Li2O and K2O results in a decrease of melt viscosity and, on a molar basis, the effect of Li2O is comparable to that of K2O. Viscosity-related properties such as activation energy of viscous flow, melt fragility and glass transition temperature are affected in a similar way by both alkali oxides. The observed effects of alkalis on the viscosity of melt are smaller when compared to an equal molar amount of OH- groups at low water content but become equal with increasing water content. Finally, it is shown that the low viscosity of pegmatite forming melts can only be explained by the combined effects of H2O, F and of non-charge balancing alkalis.
KW - Alkalis
KW - Falling sphere
KW - Lithium
KW - Micropenetration
KW - Pegmatite
KW - Viscosity
UR - http://www.scopus.com/inward/record.url?scp=84930939031&partnerID=8YFLogxK
U2 - 10.1016/j.chemgeo.2015.05.011
DO - 10.1016/j.chemgeo.2015.05.011
M3 - Article
AN - SCOPUS:84930939031
VL - 410
SP - 1
EP - 11
JO - Chemical Geology
JF - Chemical Geology
SN - 0009-2541
ER -