K and Cl concentrations on the Martian surface determined by the Mars Odyssey Gamma Ray Spectrometer: Implications for bulk halogen abundances in Mars

G. Jeffrey Taylor, William V. Boynton, Scott M. McLennan, Linda M V Martel

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Orbital gamma ray spectrometry shows that the Martian surface has a mean Cl/K ratio of 1.3 ± 0.2, indistinguishable from the ratio in CI chondrites (1.28). Although Cl and K fractionate by magma degassing and aqueous processing, during igneous partial melting both elements are highly incompatible. Thus, if the surface Cl/K reflects the bulk crustal value, then the mantle, hence primitive silicate Mars, also has a roughly CI ratio. Martian meteorite data indicate that Cl/Br is also approximately chondritic, suggesting that elements that condensed in the nebula between ∼1000 K (K and Cl) to ∼500 K (Br) are uniformly depleted in Mars at about 0.6 × CI chondrite concentrations. Mars clearly does not contain 0.6 × CI levels of H2O, which would be ∼6 wt%, indicating that Mars was constructed by planetesimals rich in volatile elements, but not in water.

Original languageEnglish (US)
Article numberL12204
JournalGeophysical Research Letters
Volume37
Issue number12
DOIs
StatePublished - Jun 2010

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gamma ray spectrometers
halogen
halogens
mars
Mars
spectrometer
chondrites
chondrite
SNC meteorites
Martian meteorite
gamma ray spectrometry
volatile element
protoplanets
planetesimal
degassing
nebulae
magma
partial melting
silicates
Earth mantle

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)
  • Geophysics

Cite this

K and Cl concentrations on the Martian surface determined by the Mars Odyssey Gamma Ray Spectrometer : Implications for bulk halogen abundances in Mars. / Taylor, G. Jeffrey; Boynton, William V.; McLennan, Scott M.; Martel, Linda M V.

In: Geophysical Research Letters, Vol. 37, No. 12, L12204, 06.2010.

Research output: Contribution to journalArticle

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