Results 161 to 170 of about 15,904 (206)

Oxygen fugacity constraints on the southern African lithosphere

Contributions to Mineralogy and Petrology, 1991
Oxygen fugacities are calculated for olivine—spinel ±orthopyroxene assemblages recovered from diamonds and the concentrate of the Dokolwayo kimberlite, Swaziland. In addition thermobarometric oxygen fugacities are obtained for chrome spinel-garnet peridotites and diamonds from several other southern African kimberlites. The southern African lithosphere
Gurney, J. J., Daniels, L. R. M.
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Intrinsic oxygen fugacities of diogenites and mesosiderite clasts

Geochimica et Cosmochimica Acta, 1984
Oxygen fugacities of diogenite and mesosiderite clast material were measured with the double ZrO2 cell technique between 800 and 1150 C. The samples were taken from large clasts in the diogenites Johnstown (En73) and Tatahouine (En75), and the mesosiderites Estherville (En81), West Point (Fo88) and Emery (En68).
Roger H. Hewins, G.C. Ulmer
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Oxygen fugacity control in piston-cylinder experiments

Contributions to Mineralogy and Petrology, 2012
The main goal of this study was to develop and test a capsule assembly for use in piston-cylinder experiments where oxygen fugacity could be controlled in the vicinity of the QFM buffer without H2O loss or carbon contamination of the sample material. The assembly consists of an outer Pt-capsule containing a solid buffer (Ni–NiO or Co–CoO) plus H2O and ...
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Exoplanetary oxygen fugacities from polluted white dwarf stars

Proceedings of the International Astronomical Union, 2019
AbstractThe intrinsic oxygen fugacity of a planet profoundly influences a variety of its geochemical and geophysical aspects. Most rocky bodies in our solar system formed with oxygen fugacities approximately five orders of magnitude higher than that corresponding to a hydrogen-rich gas of solar composition.
Alexandra E. Doyle, Beth Klein, Ben Zuckerman, Hilke E. Schlichting, Edward D. Young   +4 more
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The magmatic oxygen fugacity of an ultrabasic dyke

Contributions to Mineralogy and Petrology, 1971
The magmatic oxygen fugacity (fO2) of a thirty foot wide feldspathic peridotite dyke has been determined using the experimental method of Fudali (1965). Determinations were made on samples from both the marginal and central portions of the dyke and a difference of approximately one order of magnitude in fO2 was observed.
Henderson, C. M. B., Gibb, F. G. F.
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Measurement and control of oxygen fugacity during annealing

Review of Scientific Instruments, 1984
We describe a simple analog electronic circuit to measure the voltages of a thermocouple and solid electrolyte sensor and calculate and diplay the temperature and log fO2. This circuit monitors conditions in a simple annealing system where the oxygen atmosphere is controlled by continuous flow of a gas buffer.
John P. Shepherd, Charles J. Sandberg
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Oxygen fugacities of basaltic and andesitic magmas

Geochimica et Cosmochimica Acta, 1965
Experimentally determined oxygen fugacities in equilibrium with the original ferrous to ferric iron ratios of nine basalts and andesites range from 10−8·5 to 10−6·4 atm at 1200°C. There is a strong tendency for the ƒO2 to increase with increasing acidity of the rocks studied.
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Oxygen fugacity of the diamond + CO fluid assemblage and CO2 fugacity at 8 GPa

Earth and Planetary Science Letters, 1994
Abstract We have bracketed the oxygen fugacity ( ƒ O 2 ) of the diamond + CO fluid buffer (CCO) relative to the wustite-magnetite (WM) and nickel-nickel oxide (NNO) buffers at 8 GPa and 950–1550°C using a Walker-style multi-anvil press. The intersection of CCO with WM is between 1050° and 1150°C and thus the log ƒ O 2 of CCO at
Tom LaTourrette, John R. Holloway
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Sodic Amphiboles as Oxygen Fugacity Indicators in Metamorphism

The Journal of Geology, 1980
Analyses of sodic amphiboles from a blueschist metamorphic terrain of constant grade in the Tavsanli area, Northwest Turkey, show that practically the whole range of sodic amphibole compositions is stable in the glaucophane-lawsonite facies. By analysing sodic amphiboles coexisting with magnetite and hematite, it has proved possible to plot for a ...
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Oxygen diffusion in olivine: Effect of oxygen fugacity and implications for creep

Journal of Geophysical Research: Solid Earth, 1989
Oxygen self‐diffusion experiments on single crystals of San Carlos olivine (∼Fo92) at 1200° ≤ T ≤ 1400°C, oxygen fugacities (ƒO2) along the Ni‐NiO and Fe‐FeO buffers, and silica activity at the olivine‐orthopyroxene buffer yielded results that follow the relationshipD= 2.6 × 10−10ƒO20.21±0.03exp [−266±11 (kJ mol−1/RT)], whereDis the diffusion ...
F. J. Ryerson, W. B. Durham, D. J. Cherniak, W. A. Lanford   +3 more
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