Redox conditions on small bodies, the moon and mars

Research output: Chapter in Book/Report/Conference proceedingChapter

57 Citations (Scopus)

Abstract

The current state of knowledge regarding redox conditions of rocks from asteroidal bodies (as represented by various classes of meteorites), the Moon and Mars is discussed here. In the case of the differentiated meteorite parent bodies, the redox conditions range over at least six orders of magnitude (from ~5 log units below the Iron-Wustite buffer to slightly above it) and are determined in large part by the compositions of the undifferentiated precursor materials that accreted to form these parent bodies. Lunar basalts record oxygen fugacities ranging from close to the Iron-Wustite (IW) buffer to ~2 log units below it. The current best estimate of the oxygen fugacity of the lunar mantle is ~ 1 log unit below IW. Martian crustal rocks represented by the Shergottite-Nakhlite-Chassignite group of meteorites record a wide range of oxygen fugacities. The basaltic shergottites range from slightly below the IW buffer to ~2 log units above it, whereas the cumulate nakhlites (and chassignites) are relatively oxidized (-3-4 log units above the IW buffer). Following early metal-silicate and crust-mantle differentiation on Mars, the depleted martian mantle is likely to have been reduced (close to the IW buffer or slightly lower). Metasomatism and secondary (hydrous) alteration are likely to have produced silicate reservoirs on Mars that are relatively more oxidized (most likely ≥3 log units above the IW buffer). The redox conditions on the other terrestrial planets (Mercury and Venus) are not well constrained. Based on the limited information from remote spacecraft and telescopic observations of surface rocks on these planets, it is inferred that silicate reservoirs on Mercury are highly reduced; those on Venus are likely to be somewhat more oxidized than on Mercury, possibly similar to the lower mantle of Earth.

Original languageEnglish (US)
Title of host publicationOxygen in the Solar System
PublisherDe Gruyter Mouton
Pages493-510
Number of pages18
ISBN (Electronic)9781501508509
ISBN (Print)9780939950805
DOIs
StatePublished - Nov 15 2018

Fingerprint

redox conditions
Moon
Mars
iron
fugacity
meteorite
silicate
parent body
Venus
oxygen
lunar mantle
Mercury (planet)
shergottite
rock
mantle
lower mantle
cumulate
metasomatism
spacecraft
planet

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)

Cite this

Wadhwa, M. (2018). Redox conditions on small bodies, the moon and mars. In Oxygen in the Solar System (pp. 493-510). De Gruyter Mouton. https://doi.org/10.2138/rmg.2008.68.17

Redox conditions on small bodies, the moon and mars. / Wadhwa, Meenakshi.

Oxygen in the Solar System. De Gruyter Mouton, 2018. p. 493-510.

Research output: Chapter in Book/Report/Conference proceedingChapter

Wadhwa, M 2018, Redox conditions on small bodies, the moon and mars. in Oxygen in the Solar System. De Gruyter Mouton, pp. 493-510. https://doi.org/10.2138/rmg.2008.68.17
Wadhwa M. Redox conditions on small bodies, the moon and mars. In Oxygen in the Solar System. De Gruyter Mouton. 2018. p. 493-510 https://doi.org/10.2138/rmg.2008.68.17
Wadhwa, Meenakshi. / Redox conditions on small bodies, the moon and mars. Oxygen in the Solar System. De Gruyter Mouton, 2018. pp. 493-510
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