High pressure effects on the iron iron oxide and nickel nickel oxide oxygen fugacity buffers

Journal Article · Fri Sep 25 04:00:00 EDT 2009 · Earth and Planetary Science Letters

DOI:https://doi.org/10.1016/j.epsl.2009.07.022· OSTI ID:1005880

Campbell, Andrew J; Danielson, Lisa; Righter, Kevin; Seagle, Christopher T; Wang, Yanbin; Prakapenka, Vitali B

The chemical potential of oxygen in natural and experimental samples is commonly reported relative to a specific oxygen fugacity (fO{sub 2}) buffer. These buffers are precisely known at 1 bar, but under high pressures corresponding to the conditions of the deep Earth, oxygen fugacity buffers are poorly calibrated. Reference (1 bar) fO{sub 2} buffers can be integrated to high pressure conditions by integrating the difference in volume between the solid phases, provided that their equations of state are known. In this work, the equations of state and volume difference between the metal-oxide pairs Fe-FeO and Ni-NiO were measured using synchrotron X-ray diffraction in a multi-anvil press and laser heated diamond anvil cells. The results were used to construct high pressure fO{sub 2} buffer curves for these systems. The difference between the Fe-FeO and Ni-NiO buffers is observed to decrease significantly, by several log units, over 80 GPa. The results can be used to improve interpretation of high pressure experiments, specifically Fe-Ni exchange between metallic and oxide phases.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: USDOE
• OSTI ID: 1005880
• Journal Information: Earth and Planetary Science Letters, Journal Name: Earth and Planetary Science Letters Journal Issue: (3-4) ; 09, 2009 Vol. 286; ISSN 0012-821X; ISSN EPSLA2
• Publisher: Elsevier
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

43 PARTICLE ACCELERATORS
BUFFERS
DIAMONDS
EQUATIONS OF STATE
LASERS
OXIDES
OXYGEN
SYNCHROTRONS
X-RAY DIFFRACTION