An expanded structural geobarometer for anhydrous and hydrous, basic and ultrabasic systems
Article Abstract:
Coexisting melts of basanite and picrobasalt starting materials span a wide range of petrologically relevant anhydrous and hydrous compositions at pressure conditions pertinent to the earth's crust and uppermost mantle in a variety of oxygen fugacity conditions and mineral assemblages. Unit-cell volume of clinopyroxenes at a given pressure is linearly and negatively correlated with the M1 site volume. Unit-cell volume and M1 site volume decrease linearly as pressure increases for a fixed melt composition due to a combination of M1, M2 and temperature site exchanges.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1998
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Structural geobarometers for basic to acid, tholeiitic and mildly alkaline magmatic systems
Article Abstract:
The crystal structures of several experimentally prepared, igneous clinopyroxenes were determined from electroprobe chemical data. The unit-cell volume versus M1-polyhedron volume relations were analyzed over a range of pressures and temperatures. Data obtained from structure modeling and corrected for thermal expansivity and compressibility were utilized to carry out the analysis. Results indicated that pressure and clinopyroxene structural parameters were dependent on the nature of the coexisting melt.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1999
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A clinopyroxene geobarometer for basaltic systems based on crystal-structure modeling
Article Abstract:
A crystal-structure simulation is done using available experimental chemical data to study crystal chemical response of basalt clinopyroxene to increasing pressure. Clinopyroxene behavior in a magmatic environment is greatly influenced by pressure. An empirical geobarometer, based on relationship of cell volume and M1-site volume, is made using the fact that there is internal consistency of simulation data. Construction and working of the geobarometer are discussed.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1995
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