| type de publication : |
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Articles dans des revues avec comité de lecture |
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| domaine : |
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Planète et Univers/Sciences de la Terre/Volcanologie
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| titre : |
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The effect of temperature and bulk composition on the solution mechanism of phosphorus in peraluminous haplogranitic magma. |
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| auteur(s) : |
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B. O. Mysen 1, François Holtz 2, Michel Pichavant ( ) 2, Jean-Michel Bény () 2, J.M. Montel 3 |
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| laboratoire : |
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| résumé : |
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Solution mechanisms of P in peraluminous glasses and melts in the system CaO-Na2O-K2O-Al2O3- SiO2-P2O5 have been examined with in-situ microRaman spectroscopy from ambient temperature to near 1200 °C. The principal aim was to examine the relative stabilities of phosphate complexes as functions of P content, peraluminosity, and temperature. Increasing peraluminosity was accomplished by increasing the proportions of Al3+ and Ca2+ of constant SiO2 content. The molar ratio Al2O3/ (CaO+Na2O+K2O) (A/CNK) ranged from ~1 to ~1.3. In all compositions, P5+ is bonded to Al3+ to form AlPO4 complexes. In addition, there is evidence for pyrophosphate complexing (P2O7). In melts with the highest (Ca+Na+K)/P, there is probably also a small fraction of orthophosphate complexes present. The relative importance of AlPO4-like complexes is correlated positively with peraluminosity (A/CNK), P2O5 content, and increasing temperature at temperatures above that of the glass transition. These structural relationships among phosphate complexes are coupled with decreasing polymerization of the aluminosilicate melts. |
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langue du texte
intégral : |
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Anglais |
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| journal : |
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| American Mineralogist |
| Publisher |
Mineralogical Society of America |
| ISSN |
0003-004X |
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| date de publication : |
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1999 |
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| volume : |
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84 |
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| page, identifiant, ... : |
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1336-1345 |
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