Details
| Original language | English |
|---|---|
| Pages (from-to) | 137-152 |
| Number of pages | 16 |
| Journal | European Journal of Mineralogy |
| Volume | 4 |
| Issue number | 1 |
| Publication status | Published - 31 Jan 1992 |
Abstract
Liquidus phase relationships have been investigated in the peraluminous system Qz (SiO2) - Ab (NaAlSi3O8) - Or (KAlSi3O8) - Al2O3 - H2O - CO2. The experiments have been performed at 2kbar, 750 to 850°C, and at H2O-undersaturated conditions (H2O-activity close to 0.5). An aluminosilicate phase (mullite) coexists with all melts of peraluminous compositions. The comparison of the subaluminous and the peraluminous systems shows that all liquidus temperatures are lower in the peraluminous system. The position of the quartz-feldspar cotectic is slightly shifted towards more Qz-rich compositions in the peraluminous system. The projected composition of the thermal minimum is Qz35Ab36 Or29 in the subaluminous system and Qz38Ab34Or28 in the peraluminous system. Peraluminous melts coexisting with mullite contain 1.2 to 2.4% normative corundum at the investigated temperatures (750 to 850°C). Different temperatures have not been observed for the beginning of melting of crystal mixtures composed of quartz + alkali feldspar and quartz + alkali feldspar + sillimanite. This may be due to kinetic problems and is discussed. -from Authors
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
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In: European Journal of Mineralogy, Vol. 4, No. 1, 31.01.1992, p. 137-152.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Effect of excess aluminium on phase relations in the system Qz-Ab- Or
T2 - experimental investigation at 2kbar and reduced H2O-activity
AU - Holtz, Francois
AU - Johannes, Wilhelm
AU - Pichavant, Michel
N1 - Copyright: Copyright 2018 Elsevier B.V., All rights reserved.
PY - 1992/1/31
Y1 - 1992/1/31
N2 - Liquidus phase relationships have been investigated in the peraluminous system Qz (SiO2) - Ab (NaAlSi3O8) - Or (KAlSi3O8) - Al2O3 - H2O - CO2. The experiments have been performed at 2kbar, 750 to 850°C, and at H2O-undersaturated conditions (H2O-activity close to 0.5). An aluminosilicate phase (mullite) coexists with all melts of peraluminous compositions. The comparison of the subaluminous and the peraluminous systems shows that all liquidus temperatures are lower in the peraluminous system. The position of the quartz-feldspar cotectic is slightly shifted towards more Qz-rich compositions in the peraluminous system. The projected composition of the thermal minimum is Qz35Ab36 Or29 in the subaluminous system and Qz38Ab34Or28 in the peraluminous system. Peraluminous melts coexisting with mullite contain 1.2 to 2.4% normative corundum at the investigated temperatures (750 to 850°C). Different temperatures have not been observed for the beginning of melting of crystal mixtures composed of quartz + alkali feldspar and quartz + alkali feldspar + sillimanite. This may be due to kinetic problems and is discussed. -from Authors
AB - Liquidus phase relationships have been investigated in the peraluminous system Qz (SiO2) - Ab (NaAlSi3O8) - Or (KAlSi3O8) - Al2O3 - H2O - CO2. The experiments have been performed at 2kbar, 750 to 850°C, and at H2O-undersaturated conditions (H2O-activity close to 0.5). An aluminosilicate phase (mullite) coexists with all melts of peraluminous compositions. The comparison of the subaluminous and the peraluminous systems shows that all liquidus temperatures are lower in the peraluminous system. The position of the quartz-feldspar cotectic is slightly shifted towards more Qz-rich compositions in the peraluminous system. The projected composition of the thermal minimum is Qz35Ab36 Or29 in the subaluminous system and Qz38Ab34Or28 in the peraluminous system. Peraluminous melts coexisting with mullite contain 1.2 to 2.4% normative corundum at the investigated temperatures (750 to 850°C). Different temperatures have not been observed for the beginning of melting of crystal mixtures composed of quartz + alkali feldspar and quartz + alkali feldspar + sillimanite. This may be due to kinetic problems and is discussed. -from Authors
UR - http://www.scopus.com/inward/record.url?scp=0026497909&partnerID=8YFLogxK
U2 - 10.1127/ejm/4/1/0137
DO - 10.1127/ejm/4/1/0137
M3 - Article
AN - SCOPUS:0026497909
VL - 4
SP - 137
EP - 152
JO - European Journal of Mineralogy
JF - European Journal of Mineralogy
SN - 0935-1221
IS - 1
ER -