Are oxidized shergottite-like basalts an alternative to ‘‘andesite’’ on Mars?

[1] We acquired new thermal emission spectra of oxidized synthetic Martian meteorite-like basalts for comparison to Martian surface spectra acquired by the Mars Global Surveyor Thermal Emission Spectrometer (MGS TES). We find that true thermal emission spectra of the oxidized basalts do not provide good spectral matches to the Martian spectra. By contrast, previous biconical reflectance spectra, converted to emission spectra, appeared to fit the Mars observations well. Attempts to model the mineralogies of the oxidized basalts using a linear deconvolution algorithm and an end member set previously used to derive mineralogies for the Martian surface were unsuccessful, suggesting that the oxidized basalts contain altered phases not present in the end member set. Successful modeling of Martian surface mineralogies using the end member set indicates that it sufficiently represents the phases present on the Martian surface and does not require the altered phases needed to model the oxidized basalt mineralogies. Although oxidized Martian meteorite-like basalts may be viable analogues for some Martian materials, our results suggest that they cannot explain the two primary surface mineralogies measured by MGS TES.