Organic and inorganic interpretations of the martian UV–IR reflectance spectrum

Ultraviolet spectral reflectance properties of common planetary minerals

“…The overall decrease in reflectance toward shorter wavelengths and the absorption band near 230 nm are also seen in other magnetite spectra (Strens and Wood, 1979;Hapke et al, 1978;Wagner et al, 1987). The absorption coefficient of magnetite peaks near 230 nm (Pang et al, 1982). The absorption features can be attributed to octahedrally-coordinated Fe 3+ and Fe 2+ (Loeffler et al, 1974;Tossell et al, 1974).…”

“…For example, in Mariner 9 ultraviolet observations of Mars airborne dust, Pang et al (1982) detected spectral features near 210, 250, and 300 nm that they assigned to Ti-O charge transfers in the anatase polymorph of TiO 2 . This assignment was bolstered by the detection of Ti by the Viking landers and the lack of other spectral analogues for these features.…”

UVolution, a Photochemistry Experiment in Low Earth Orbit: Investigation of the Photostability of Carboxylic Acids Exposed to Mars Surface UV Radiation Conditions

“…Indeed, the surface of Mars is considered to be an oxidative environment, and it is hypothesized that one or more oxidants that could destroy organic matter are present in the regolith. This reactivity could be attributed to the presence of catalyzers, one or more inorganic superoxides or peroxides in the martian regolith (Chun et al, 1978;Pang et al, 1982;Yen et al, 2000), H 2 O 2 [recently detected (Clancy et al, 2004;Encrenaz et al, 2004)] diffusion into the regolith (Bullock et al, 1994), or the presence of perchlorates (Hecht et al, 2009). Results of a theoretical study led by Benner et al (2000) with regard to the oxidative action on organic molecules of meteoritic origin in the martian soil show that such compounds should not be entirely oxidized into volatile molecules (i.e., CO 2 and H 2 O).…”

“…Yen et al (2000) showed that the interaction of UV radiation with a mineral matrix (labradorite, feldspar) and an oxygen-rich atmosphere could produce one or more inorganic superoxides or peroxides that are able to destroy the organic matter. Chun et al (1978) and Pang et al (1982) showed that TiO 2 catalyzed the oxidation of organics in the presence of oxygen. In our experiment, no rich oxygen atmosphere was present, but the JSC Mars-1 soil contained TiO 2 , as does the martian regolith (Allen et al, 1998).…”

“…Results of our experiments, therefore, imply that a martian soil analogue might play a role in the photocatalytic degradation of organic compounds on Mars. Several laboratory experiments have been conducted to investigate the interaction of UV radiation with a mineral matrix (Chun et al, 1978;Pang et al, 1982;Yen et al, 2000). Yen et al (2000) showed that the interaction of UV radiation with a mineral matrix (labradorite, feldspar) and an oxygen-rich atmosphere could produce one or more inorganic superoxides or peroxides that are able to destroy the organic matter.…”