Oxygen fugacity and geochemical variations in the martian basalts: implications for martian basalt petrogenesis and the oxidation state of the upper mantle of Mars

Herd, Christopher D. K.; Borg, L. E.; Jones, J. H.; Papike, J. J.

doi:10.1016/s0016-7037(02)00828-1

Cited by 265 publications

(328 citation statements)

References 40 publications

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“…Although oxygen fugacity (fO 2 ) greatly affects mineral stability with implications for trace element partitioning (Herd et al, 2002), its effect is not considered in these models. We selected mineral assemblages on the basis of experiments near the QFM (quartzfayalite-magnetite) buffer by Monders et al (2007), and CIPW norms (McSween et al, 2006a(McSween et al, , 2006b) that are based on in situ measurements of Fe …”

Section: Relating Gusev Basalts By Igneous Processesmentioning

confidence: 99%

The evolution of a heterogeneous Martian mantle: Clues from K, P, Ti, Cr, and Ni variations in Gusev basalts and shergottite meteorites

Schmidt

McCoy

2010

Earth and Planetary Science Letters

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Section: Relating Gusev Basalts By Igneous Processesmentioning

confidence: 99%

The evolution of a heterogeneous Martian mantle: Clues from K, P, Ti, Cr, and Ni variations in Gusev basalts and shergottite meteorites

Schmidt

McCoy

2010

Earth and Planetary Science Letters

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“…Even though the bulk Fe 3C / P Fe content of the mantle is relatively low (2-3%), oxygen fugacities calculated from ferric-ferrous equilibria involving spinel are high because f O 2 is proportional to the activity of Fe 2 O 3 in spinel (O'Neill et al 1993b). At higher pressures, this is no longer the case and ferric Fe becomes dissolved in minerals such as garnet, which have larger modal abundances (O'Neill et al 1993b; ( Wadhwa 2001;Herd et al 2002) and for Lunar basalts (Papike et al 2004) are also shown. IW, iron-wüstite; FMQ, fayalite-magnetite-quartz; NNO, Ni-NiO redox buffer.…”

Section: The Redox State Of the Present-day Mantlementioning

confidence: 99%

The redox state of the mantle during and just after core formation

Frost

Mann

Asahara

et al. 2008

Phil. Trans. R. Soc. A.

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Siderophile elements are depleted in the Earth's mantle, relative to chondritic meteorites, as a result of equilibration with core-forming Fe-rich metal. Measurements of metal-silicate partition coefficients show that mantle depletions of slightly siderophile elements (e.g. Cr, V ) must have occurred at more reducing conditions than those inferred from the current mantle FeO content. This implies that the oxidation state (i.e. FeO content) of the mantle increased with time as accretion proceeded. The oxygen fugacity of the present-day upper mantle is several orders of magnitude higher than the level imposed by equilibrium with core-forming Fe metal. This results from an increase in the Fe 2 O 3 content of the mantle that probably occurred in the first 1 Ga of the Earth's history. Here we explore fractionation mechanisms that could have caused mantle FeO and Fe 2 O 3 contents to increase while the oxidation state of accreting material remained constant (homogeneous accretion). Using measured metal-silicate partition coefficients for O and Si, we have modelled core-mantle equilibration in a magma ocean that became progressively deeper as accretion proceeded. The model indicates that the mantle would have become gradually oxidized as a result of Si entering the core. However, the increase in mantle FeO content and oxygen fugacity is limited by the fact that O also partitions into the core at high temperatures, which lowers the FeO content of the mantle. (Mg,Fe)(Al,Si)O 3 perovskite, the dominant lower mantle mineral, has a strong affinity for Fe 2 O 3 even in the presence of metallic Fe. As the upper mantle would have been poor in Fe 2 O 3 during core formation, FeO would have disproportionated to produce Fe 2 O 3 (in perovskite) and Fe metal. Loss of some disproportionated Fe metal to the core would have enriched the remaining mantle in Fe 2 O 3 and, if the entire mantle was then homogenized, the oxygen fugacity of the upper mantle would have been raised to its present-day level.

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“…The degree to which Martian magmas may have assimilated crustal material, thus altering the geochemical signatures acquired from their mantle sources, is unclear 1 . This issue features prominently in efforts to understand whether the source of light rare-earth elements in enriched shergottites lies in crustal material incorporated into melts 1,2 or in mixing between enriched and depleted mantle reservoirs 3 . Sulphur isotope systematics offer insight into some aspects of crustal assimilation.…”

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confidence: 99%