HR: 1330h
AN: P22A-0064    [PDF]
TI: Development of chemical indicators of aqueous alteration on Mars with applications to the 2004 MER landing sites
AU: * Greenwood, J P
EM: james.greenwood@yale.edu
AF: Dept. Geology and Geophysics, Yale University, Kline Geology Lab, New Haven, CT 06520 United States
AU: Blake, R E
EM: ruth.blake@yale.edu
AF: Dept. Geology and Geophysics, Yale University, Kline Geology Lab, New Haven, CT 06520 United States
AB: Data collected by the Mars Odyssey Gamma Ray Spectrometer (GRS) and Mars Exploration Rover Alpha Particle X-ray Spectrometers (MER-APXS) will allow for unprecedented chemical information to be obtained from the Martian surface. Phosphorous and iron are two elements that should be measured with some accuracy by MER-APXS (as opposed to MPF). The well-known affinity of iron oxide/hydroxides for sorption of phosphate in oceans, lakes, rivers, and soils will be used to assess the utility of P/Fe (in conjunction with other elements and element ratios measurable by MER-APXS) as an indicator of aqueous activity at the two 2004 MER landing sites. Iron oxide/hydroxides are also an effective sink for Th in terrestrial waters; thus, GRS data may also be valuable in evaluating the nature of aqueous alteration (or lack thereof) at the MER landing sites. For example, the hematite-bearing deposit in Sinus Meridiani (2S, 4W) has a high Th concentration and low K/Th, suggesting that sorption of Th by specular hematite in aqueous solution may have occurred at some point in the geologic history of this region of Mars. Experiments on the sorptive properties of specular hematite and palagonite for PO4 and Th will be used to develop a model for the role of water in formation of deposits at the two MER landing sites.
DE: 1060 Planetary geochemistry (5405, 5410, 5704, 5709, 6005, 6008)
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting