An experimental study of rare earth element partitioning between a shergottite melt and pigeonite: implications for the oxygen fugacity of the mart ian interior

McCanta, M. C.; Rutherford, M. J.; Jones, J. H.

doi:10.1016/j.gca.2003.10.019

Cited by 42 publications

(56 citation statements)

References 38 publications

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“…Since Sm is monovalent and unaffected by changes in fO 2 , changes in the Eu/Sm ratios with fO 2 reflect changes in the Eu 2+ /Eu 3+ ratio. As shown in previous studies (i.e., McKay et al 1994;McCanta et al 2004), D(Eu/Sm) pyroxene/melt increases as the system fO 2 increases and decreases as the system fO 2 decreases.…”

Section: Introductionsupporting

confidence: 76%

“…Finally, the accuracy of the Eu-oxybarometer decreases markedly around an fO 2 of QFM. This results from the essentially total oxidation of Eu 2+ to Eu 3+ under these fO 2 conditions (e.g., McKay et al 1994;McCanta et al 2004). The slope of the oxybarometer calibration curve begins to flatten at this juncture preventing extrapolations to higher fO 2 's.…”

Section: Use Of the Eu-oxybarometermentioning

confidence: 99%

“…Based on a variety of analytical methods, the basaltic shergottites, a class of meteorites from Mars, exhibit a range of intrinsic fO 2 values spanning 2-3 orders of magnitude including several meteorites that indicate they were crystallized under fairly oxidizing conditions (Wadhwa 2001;Herd et al 2002;McCanta et al 2004;Karner et al 2007b). The fO 2 of the cumulate Martian meteorites (Goodrich et al 2003;Herd 2003) suggests they fall within a similar range as the basaltic shergottites.…”

Section: Introductionmentioning

confidence: 99%

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Expanding the application of the Eu‐oxybarometer to the lherzolitic shergottites and nakhlites: Implications for the oxidation state heterogeneity of the Martian interior

McCanta¹,

Elkins-Tanton²,

Rutherford³

2009

Meteorit & Planetary Scien

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Section: Introductionsupporting

confidence: 76%

Section: Use Of the Eu-oxybarometermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Expanding the application of the Eu‐oxybarometer to the lherzolitic shergottites and nakhlites: Implications for the oxidation state heterogeneity of the Martian interior

McCanta¹,

Elkins-Tanton²,

Rutherford³

2009

Meteorit & Planetary Scien

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“…Line is the fit to dataset of Herd (2003) but more recent additions show that this is more complicated. Oxygen fugacity data are from Goodrich et al 2003;Herd et al 2001Herd et al , 2002Herd 2003Herd , 2006McCanta et al (2004b);Wadhwa 2001;Karner et al 2007;Shearer et al 2006; La and Yb data are from references compiled by C. Meyer, Mars Meteorite Compendium 2008 webpage). Conversion between IW and FMQ buffers was done using calibration of O'Neill (1988) for IW and O'Neill (1987) for FMQ; at magmatic temperatures the relative difference is ~3.5 log fO 2 units.…”

Section: Mineral Composition and Structurementioning

confidence: 99%

“…The fO 2 of shergottites has been determined using a number of different approaches including Eu/Gd partitioning between augite and melt (Wadhwa 2001) and pigeonite and melt (McCanta et al 2004b), and olivine-orthopyroxenespinel equilibria (Goodrich et al 2003;Righter and Drake 1996). In addition to these studies which report specific fO 2 calculations, several studies have shown a large variation in ferric iron and V contents in ferromagnesian silicates and spinels (Delaney and Dyar 2003;Papike et al 2004;).…”

Section: Shergottitesmentioning

confidence: 99%

Oxygen fugacity in the Martian mantle controlled by carbon: New constraints from the nakhlite MIL 03346

Righter

Yang

Costin

et al. 2008

Meteorit & Planetary Scien

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This trend can be explained by polybaric graphite-CO-CO 2 equilibria in the Martian mantle. Shergottites would have formed at pressures between 1.2 and 3.0 GPa, and nakhlite parent liquids formed at pressures >3.0 GPa, consistent with geochemical and petrologic data for the shergottites and nahklites. Carbon buffering in the Martian mantle could be responsible for variation in fO 2 in Martian meteorites (rather than assimilation or crustal interaction), as well as C-H-O fluids that could be the source of ~30 ppb CH 4 detected by recent spacecraft missions. The conundrum of an oxidized current mantle and basalts, but reduced early mantle during core-mantle equilibrium exists for both the Earth and Mars. A polybaric buffering role for graphite can explain this discrepancy for Mars, and thus it may not be necessary to have an oxidation mechanism like the dissociation of MgFe-perovskite to account for the oxidized terrestrial mantle.

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Geologic history of Martian regolith breccia Northwest Africa 7034: Evidence for hydrothermal activity and lithologic diversity in the Martian crust

et al. 2016

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The timing and mode of deposition for Martian regolith breccia Northwest Africa (NWA) 7034 were determined by combining petrography, shape analysis, and thermochronology. NWA 7034 is composed of igneous, impact, and brecciated clasts within a thermally annealed submicron matrix of pulverized crustal rocks and devitrified impact/volcanic glass. The brecciated clasts are likely lithified portions of Martian regolith with some evidence of past hydrothermal activity. Represented lithologies are primarily ancient crustal materials with crystallization ages as old as 4.4 Ga. One ancient zircon was hosted by an alkali‐rich basalt clast, confirming that alkalic volcanism occurred on Mars very early. NWA 7034 is composed of fragmented particles that do not exhibit evidence of having undergone bed load transport by wind or water. The clast size distribution is similar to terrestrial pyroclastic deposits. We infer that the clasts were deposited by atmospheric rainout subsequent to a pyroclastic eruption(s) and/or impact event(s), although the ancient ages of igneous components favor mobilization by impact(s). Despite ancient components, the breccia has undergone a single pervasive thermal event at 500–800°C, evident by groundmass texture and concordance of ~1.5 Ga dates for bulk rock K‐Ar, U‐Pb in apatite, and U‐Pb in metamict zircons. The 1.5 Ga age is likely a thermal event that coincides with rainout/breccia lithification. We infer that the episodic process of regolith lithification dominated sedimentary processes during the Amazonian Epoch. The absence of pre‐Amazonian high‐temperature metamorphic events recorded in ancient zircons indicates source domains of static southern highland crust punctuated by episodic impact modification.

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An experimental study of rare earth element partitioning between a shergottite melt and pigeonite: implications for the oxygen fugacity of the mart ian interior

Cited by 42 publications

References 38 publications

Expanding the application of the Eu‐oxybarometer to the lherzolitic shergottites and nakhlites: Implications for the oxidation state heterogeneity of the Martian interior

Expanding the application of the Eu‐oxybarometer to the lherzolitic shergottites and nakhlites: Implications for the oxidation state heterogeneity of the Martian interior

Oxygen fugacity in the Martian mantle controlled by carbon: New constraints from the nakhlite MIL 03346

Geologic history of Martian regolith breccia Northwest Africa 7034: Evidence for hydrothermal activity and lithologic diversity in the Martian crust

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