¹L. He,²R. E. Arvidson,¹J. A. O’Sullivan,³R. V. Morris,²T. Condus,²M. N. Hughes,⁴K. E. Powell
Journal of Geophysical Research (Planets)(In Press) Open Access Link to Article [https://doi.org/10.1029/2021JE007092]
¹Department of Electrical and Systems Engineering, Washington University in St. Louis, MO
²Department of Earth and Planetary Science, Washington University in St. Louis, MO
³NASA/Johnson Space Center, Houston, TX
⁴School of Earth and Space Exploration, Arizona State University, AZ
Published by arrangement with John Wiley & Sons

The Mars Reconnaissance Orbiter Compact Imaging Spectrometer for Mars (CRISM) covers the spectral range from 0.362 to 3.92 µm with a midafternoon local solar time data acquisition. For equatorial to midlatitudes, depending on the season and surface materials, wavelengths longer than ∼2.65 µm exhibit spectral radiances on sensor that include sunlight and thermal-emission related terms. We developed a radiative transfer based neural network approach to model both solar and emitted terms in which surface kinetic temperatures are retrieved for each image pixel, together with single scattering albedo (SSA) spectra, over the full CRISM wavelength range. We applied the method to along-track oversampled scene FRT00021C92 over Glen Torridon within Gale Crater, where the Curiosity rover traversed and acquired remote sensing and in-situ data. Synergistic analysis of orbital and rover-based data, coupled with laboratory analyses of ferric-rich smectites, provide a self-consistent set of results for the presence of desiccated nontronite associated with Murray formation mudstones exposed as periodic bedrock ridges located just to the south of Vera Rubin ridge. The desiccated nature is consistent with Curiosity’s CheMin data, which for Glen Torridon drill samples indicate an abundance of nontronite having a collapsed structure resulting from loss of interlayer H2O.

^1,2Candice C. Bedford et al. (>10)
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2021JE007100]
¹Lunar and Planetary Institute, Universities Space Research Association, Houston, Texas, USA
²Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, Texas, USA
Published by arrangement with John Wiley & Sons

Aeolian processes have shaped and contributed to the geological record in Gale crater, Mars, long after the fluviolacustrine system existed ∼3 Ga ago. Understanding these aeolian deposits, particularly those which have been lithified and show evidence for aqueous alteration, can help to constrain the environment at their time of deposition and the role of liquid water later in Mars’ history. The NASA Curiosity rover investigated a prominent outcrop of aeolian sandstone within the Stimson formation at the Greenheugh pediment as part of its investigation of the Glen Torridon area. In this study, we use geochemical data from ChemCam to constrain the effects of aeolian sedimentary processes, sediment provenance, and diagenesis of the sandstone at the Greenheugh pediment, comparing the Greenheugh data to the results from previous Stimson localities situated 2.5 km north and >200 m lower in elevation. Our results, supported by mineralogical data from CheMin, show that the Stimson formation at the Greenheugh pediment was likely sourced from an olivine-rich unit that may be present farther up the slopes of Gale crater’s central mound. Our results also suggest that the Greenheugh pediment Stimson formation was cemented by surface water runoff such as that which may have formed Gediz Vallis. The lack of alteration features in the Stimson formation at the Greenheugh pediment relative to those of the Emerson and Naukluft plateaus suggests that groundwater was not as available at this locality compared to the others. However, all sites share diagenesis at the unconformity.