Details
| Original language | English |
|---|---|
| Pages (from-to) | 57-64 |
| Number of pages | 8 |
| Journal | Transactions of the Royal Society of Edinburgh, Earth Sciences |
| Volume | 87 |
| Issue number | 1-2 |
| Publication status | Published - 1996 |
Abstract
New experimental determinations of water solubility in haplogranitic melts (anhydrous compositions in the system Qz-Ab-Or and binary joins) and of the viscosity of hydrous Qz28Ab38Or34 melts (normative proportions) and natural peraluminous leucogranitic melt (Gangotri, High Himalaya) are used to constrain the evolution of viscosity of ascending magmas, depending on their P-T paths. At constant pressure, in the case of fluid-absent melting conditions, with water as the main volatile dissolved in the melts, the viscosity of melts generated from quartzo-feldspathic protoliths is lower at low temperature than at high temperature (difference of 1-2 log units between 700 and 900°C). This is due to the higher water contents of the melts at low temperature than at high temperature and to the fact that decreasing temperature does not counterbalance the effect of increasing melt water content. In ascending magmas generated from crustal material the magma viscosity does not change significantly whatever the P-T path followed (i.e. path with cooling and crystallisation; adiabatic path with decompression melting) as long as the crystal fraction is low enough to assume a Newtonian behaviour (30-50% crystals, depending on size and shape). Comparison of the properties of natural and synthetic systems suggests that both water solubility and the viscosity of multicomponent natural felsic melts (with less than 30-35% normative Qz) can be extrapolated from those of the equivalent synthetic feldspar melts.
Keywords
- Aluminosilicate melts, Crystallisation paths, Granites, Viscosity, Water solubility
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Earth and Planetary Sciences (miscellaneous)
- Earth and Planetary Sciences(all)
- Palaeontology
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In: Transactions of the Royal Society of Edinburgh, Earth Sciences, Vol. 87, No. 1-2, 1996, p. 57-64.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Water contents of felsic melts
T2 - Application to the rheological properties of granitic magmas
AU - Holtz, Francois
AU - Scaillet, Bruno
AU - Behrens, Harald
AU - Schulze, Frank
AU - Pichavant, M.
N1 - Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
PY - 1996
Y1 - 1996
N2 - New experimental determinations of water solubility in haplogranitic melts (anhydrous compositions in the system Qz-Ab-Or and binary joins) and of the viscosity of hydrous Qz28Ab38Or34 melts (normative proportions) and natural peraluminous leucogranitic melt (Gangotri, High Himalaya) are used to constrain the evolution of viscosity of ascending magmas, depending on their P-T paths. At constant pressure, in the case of fluid-absent melting conditions, with water as the main volatile dissolved in the melts, the viscosity of melts generated from quartzo-feldspathic protoliths is lower at low temperature than at high temperature (difference of 1-2 log units between 700 and 900°C). This is due to the higher water contents of the melts at low temperature than at high temperature and to the fact that decreasing temperature does not counterbalance the effect of increasing melt water content. In ascending magmas generated from crustal material the magma viscosity does not change significantly whatever the P-T path followed (i.e. path with cooling and crystallisation; adiabatic path with decompression melting) as long as the crystal fraction is low enough to assume a Newtonian behaviour (30-50% crystals, depending on size and shape). Comparison of the properties of natural and synthetic systems suggests that both water solubility and the viscosity of multicomponent natural felsic melts (with less than 30-35% normative Qz) can be extrapolated from those of the equivalent synthetic feldspar melts.
AB - New experimental determinations of water solubility in haplogranitic melts (anhydrous compositions in the system Qz-Ab-Or and binary joins) and of the viscosity of hydrous Qz28Ab38Or34 melts (normative proportions) and natural peraluminous leucogranitic melt (Gangotri, High Himalaya) are used to constrain the evolution of viscosity of ascending magmas, depending on their P-T paths. At constant pressure, in the case of fluid-absent melting conditions, with water as the main volatile dissolved in the melts, the viscosity of melts generated from quartzo-feldspathic protoliths is lower at low temperature than at high temperature (difference of 1-2 log units between 700 and 900°C). This is due to the higher water contents of the melts at low temperature than at high temperature and to the fact that decreasing temperature does not counterbalance the effect of increasing melt water content. In ascending magmas generated from crustal material the magma viscosity does not change significantly whatever the P-T path followed (i.e. path with cooling and crystallisation; adiabatic path with decompression melting) as long as the crystal fraction is low enough to assume a Newtonian behaviour (30-50% crystals, depending on size and shape). Comparison of the properties of natural and synthetic systems suggests that both water solubility and the viscosity of multicomponent natural felsic melts (with less than 30-35% normative Qz) can be extrapolated from those of the equivalent synthetic feldspar melts.
KW - Aluminosilicate melts
KW - Crystallisation paths
KW - Granites
KW - Viscosity
KW - Water solubility
UR - http://www.scopus.com/inward/record.url?scp=0030427373&partnerID=8YFLogxK
U2 - 10.1017/s0263593300006477
DO - 10.1017/s0263593300006477
M3 - Article
AN - SCOPUS:0030427373
VL - 87
SP - 57
EP - 64
JO - Transactions of the Royal Society of Edinburgh, Earth Sciences
JF - Transactions of the Royal Society of Edinburgh, Earth Sciences
SN - 0263-5933
IS - 1-2
ER -