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K and Cl concentrations on the Martian surface determined by the Mars Odyssey Gamma Ray Spectrometer: Implications for bulk halogen abundances in Mars
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| Zeitschriftentitel: | Geophysical Research Letters |
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| Personen und Körperschaften: | , , , |
| In: | Geophysical Research Letters, 37, 2010, 12 |
| Format: | E-Article |
| Sprache: | Englisch |
| veröffentlicht: |
American Geophysical Union (AGU)
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| Schlagwörter: |
| Zusammenfassung: | <jats:p>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 H<jats:sub>2</jats:sub>O, which would be ∼6 wt%, indicating that Mars was constructed by planetesimals rich in volatile elements, but not in water.</jats:p> |
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| ISSN: |
0094-8276
1944-8007 |
| DOI: | 10.1029/2010gl043528 |