Olivine-Pyroxene-PtFe alloy as an oxygen geobarometer

Journal Article · Wed Jan 01 04:00:00 EST 1992 · Journal of Geology; (United States)

DOI:https://doi.org/10.1086/629577· OSTI ID:6951678

Jamieson, H E; Roeder, P L; Grant, A H ^[1]

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1. Queen's Univ., Kingston, Ontario (Canada)

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 = 1,300-1,450C, P = 1 bar and 10 kbar. The calculated log fO{sub 2} may be compared with that determined by the CO{sub 2}-H{sub 2} mixture used to control the furnace atmosphere in the 1 bar experiments and, in the case of the 10 kbar experiments, the log fO{sub 2} determined from the graphite-fluid equilibrium. The average deviation of the calculated log fO{sub 2} determined from the graphite-fluid equilibrium. The average deviation of the calculated log fO{sub 2} and that determined by other means is 0.2; the maximum absolute difference is 0.4. The distribution coefficient (K{sub d}) for Fe and Mg between coexisting olivine and pyroxene was found to range from 1.14 at x{sub Fe{sub 2}SiO{sub 4}}{sup ol} = 0.164 to 1.54 at x{sub Fe{sub 2}SiO{sub 4}}{sup ol} = 0.655, and varies systematically with the Fe/(Fe + Mg) of the phases.

• OSTI ID: 6951678
• Journal Information: Journal of Geology; (United States), Journal Name: Journal of Geology; (United States) Vol. 100:1; ISSN JGEOA; ISSN 0022-1376
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ALLOYS
ELEMENTS
EQUILIBRIUM
GEOBAROMETRY
IGNEOUS ROCKS
IRON
IRON ALLOYS
KINETICS
METALS
MINERALS
NONMETALS
OLIVINE
OXYGEN
OXYGEN COMPOUNDS
PLATINUM
PLATINUM ALLOYS
PLATINUM METAL ALLOYS
PLATINUM METALS
PLUTONIC ROCKS
PYROXENES
REACTION KINETICS
ROCKS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
THERMODYNAMIC ACTIVITY
TRANSITION ELEMENTS