The partitioning of Fe, Ni and Co between olivine, metal, and basaltic liquid: An experimental and thermodynamic investigation, with application to the composition of the lunar core

Journal Article · Tue Mar 01 00:00:00 EST 1988 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(88)90322-5· OSTI ID:5181091

Seifert, S; O'Neill, H St.C.; Brey, G ^[1]

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1. Australian National Univ., Canberra (Australia)

The partitioning of Fe, Ni and Co between Mg-rich olivine, lunar basaltic liquid and metal has been measured over a range of temperatures and pressures. The results of the olivine/metal partitioning may be compared to those predicted from thermodynamic calculation; in general, the agreement is good, although the calculated distribution coefficients are slightly greater than those experimentally determined. This discrepancy increases with increasing temperature and pressure, but it is not possible to ascertain unambiguously which thermodynamic data might be responsible. At lower temperatures, inversion of the equilibria to yield cosmothermometers for measuring the temperature of equilibration between olivine and metal gives results for the pallasite meteorites in excellent agreement with independent estimates. The results have been applied to Apollo 15 Green Glass, presumed to approximate a primitive melt from the lunar mantle, to deduce the composition of Fe-Ni-Co metal in equilibrium with the lunar mantle. This composition is approximately (by weight) 54-60% Fe, 38-45% Ni and 1% Co; consequently, if metal has separated from the lunar mantle under equilibrium conditions to form a small lunar core, this core will be nickel rich, with a Ni/Fe ratio of {approximately}0.7 {plus minus} 0.15.

• OSTI ID: 5181091
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Vol. 52:3; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
BASALT
CHEMICAL COMPOSITION
THERMODYNAMIC PROPERTIES
LUNAR MATERIALS
GEOBAROMETRY
GEOCHEMISTRY
GEOTHERMOMETRY
COBALT
ELEMENT ABUNDANCE
EQUILIBRIUM
IRON
METEORITES
MOON
NICKEL
OLIVINE
PARTITION
PLANETARY EVOLUTION
PRESSURE MEASUREMENT
TEMPERATURE MEASUREMENT
ABUNDANCE
ALKALINE EARTH METAL COMPOUNDS
CHEMISTRY
ELEMENTS
IGNEOUS ROCKS
IRON COMPOUNDS
IRON SILICATES
MAGNESIUM COMPOUNDS
MAGNESIUM SILICATES
MATERIALS
METALS
MINERALS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
ROCKS
SATELLITES
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SOLAR SYSTEM EVOLUTION
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VOLCANIC ROCKS
580000* - Geosciences