1525-1314/asset/cover.gif?v=1&s=ac13040efb1b489f4cc7083146b8ccf4f9e7917a "Journal of Metamorphic Geology")
Department of Petrology, Geological Survey of Finland, 02150 Espoo, Finland.
1525-1314/asset/JMG_left.gif?v=1&s=6db2f86eaac15ced542158bfcdb7f6ffe231adaf)
Petrology of phlogopite-sapphirine-bearing Al-Mg granulites from Ihouhaouene, In Ouzzal, Hoggar, Algeria: an example of phlogopite stability at high temperature
Article first published online: 14 DEC 2004
DOI: 10.1111/j.1525-1314.1996.00045.x
Additional Information
How to Cite
MOURI, H., GUIRAUD, M. and HENSEN, B. J. (1996), Petrology of phlogopite-sapphirine-bearing Al-Mg granulites from Ihouhaouene, In Ouzzal, Hoggar, Algeria: an example of phlogopite stability at high temperature. Journal of Metamorphic Geology, 14: 725–738. doi: 10.1111/j.1525-1314.1996.00045.x
Publication History
- Issue published online: 14 DEC 2004
- Article first published online: 14 DEC 2004
- Received 18 January 1996; revision accepted 9 April 1996.
- Abstract
- References
- Cited By
Keywords:
- F-phlogopite;
- In Ouzzal;
- P–T grids;
- sapphirine-granulites
ABSTRACT
Al-Mg granulites, with cordierite, garnet, sapphirine, orthopyroxene, sillimanite, spinel, phlogopite, K-feldspar, plagioclase and variable quartz from Ihouhaouene (In Ouzzal, Algeria), display a range of decompression textures involving the breakdown of orthopyroxene and sillimanite, and of garnet. The succession of parageneses suggests that the P–T–t evolution corresponds to decompression with cooling from peak conditions of about 950°C and 10 kbar. This decompression path is obtained from the paragenetic analysis in the FMAS system. However, according to current KFMASH grids, this P–T–t evolution should take place outside the stability field of phlogopite+quartz; yet this assemblage is probably stable during most of the P-T evolution, notably during peak metamorphism. This discrepancy is interpreted as the effect of the high content of F in phlogopite which should shift its stability limit towards higher temperature. The consequences of this shift on the phase relationships in the KFeMASH system are investigated and it is concluded that a topological inversion could exist in the F-bearing system.