Results 81 to 90 of about 113 (110)

Experimental Calibration of the Sphalerite Geobarometer

Economic Geology, 1973
The composition of sphalerite in equilibrium with pyrite + hexagonal pyrrhotite promises to be a useful geobarometer (Scott and Barnes, 1971). Solvus isobars were accurately located by hydrothermally recrystallizing sphalerite + pyrite + hexagonal pyrrhotite in aqueous alkali halide fluxes at 2.5, 5, and 7.5 kb between 325 degrees and 710 degrees C ...
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The metapelitic garnet–biotite–muscovite–aluminosilicate–quartz (GBMAQ) geobarometer

Lithos, 2007
Abstract In this contribution we have empirically calibrated the garnet–biotite–muscovite–aluminosilicate–quartz (GBMAQ) barometer using low- to medium–high-pressure, mid-grade metapelites. Application of the barometer suggests that the GBMAQ and GASP barometers show quite similar pressure estimates.
Wu, CM, Zhao, GC
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Empirical phengite geobarometer: Background, calibration, and application

Geology of Ore Deposits, 2016
Phengite is a common metamorphic mineral stable in a wide pressure range. The dependence of pressure on silicon content established in the mid-20th century allowed us to propose a phengite-based geobarometer. Recently, the phengite geobarometer was calibrated by Caddik and Thompson (2008) but in the narrow pressure range.
V. A. Kamzolkin, S. D. Ivanov, A. N. Konilov   +2 more
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Olivine-Pyroxene-PtFe Alloy as an Oxygen Geobarometer

The Journal of Geology, 1992
An equilibrium assemblage of olivine, Ca-free pyroxene, and PtFe alloy can be used to calculate oxygen fugacity at a known temperature and pressure. This oxygen geobarometer has been tested T = 1300-1450°C, P = 1 bar and 10 kbar. The calculated log $$fO_{2}$$ may be compared with that determined by the $$CO_{2}-H_{2}$$ mixture used to control the ...
H. E. Jamieson, P. L. Roeder, A. H. Grant   +2 more
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Thermodynamics of the Garnet—Plagioclase—Al2SiO5—Quartz Geobarometer

1981
Until recently, the development of mineralogic geobarometry of crustal metamorphic assemblages has lagged far behind mineralogic geothermometry. Temperatures of crystallization of metamorphic rocks can be deduced from a number of relatively reliable thermometers.
R. C. Newton, H. T. Haselton
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A new geobarometer for the assemblage biotite‐muscovite‐chlorite‐quartz

Journal of Metamorphic Geology, 1983
The equilibrium thermodynamics of the reaction:And the equilibrium constant is composed of activities formulated using ideal mixing on sites. Consideration is given to the evaluation of uncertainties in pressures calculated using the geobarometer. Preliminary testing suggests that the geobarometer has considerable potential.
ROGER POWELL, JANE A. EVANS
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A note on the calibration of the garnet-cordierite geothermometer and geobarometer

Contributions to Mineralogy and Petrology, 1974
Experimental and theoretical considerations indicate that the distribution coefficient for iron and magnesium between coexisting garnet and cordierite increases with temperature in the assemblage cordierite-garnet-sillimanite-quartz. This conclusion is confirmed by distribution coefficients from natural garnet and cordierite from geologically well ...
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Crystal Structures as Geobarometers

2006
This is an educational web page detailing a peer-reviewed mineralogy lab activity where students use crystal structure databases and visualization software to explore clinopyroxene geobarometry, analyzing structural parameters like unit cell volume to determine crystallization pressures in magmatic systems.
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Hochdruck-minerale als Geobarometer

1993
Die Stabilitatsbeziehungen der auf Seite 371 f. aufgefuhrten Hochdruck-Minerale sind in jungerer Zeit von experimentell arbeitenden Mineralogen und Petrologen eingehend untersucht worden. Die meisten dieser Minerale gehoren dem chemisch relativ einfachen Modellsystem MgO-Al2O3-SiO2-H2O (abgekurzt MASH) an (Abb. 145, Hilfsfigur links oben).
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Experimental calibration of a garnet–clinopyroxene geobarometer for mantle eclogites

Contributions to Mineralogy and Petrology, 2015
Thermodynamic parameters have been calibrated for a geobarometer suitable for use on eclogitic mantle xenoliths. The barometer is based on the incorporation of tetrahedrally coordinated aluminum in clinopyroxene coexisting with garnet and has been calibrated using the results of piston cylinder and multi-anvil experiments performed between pressures of
C. Beyer, D. J. Frost, N. Miyajima
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