¹L. He,²R. E. Arvidson,²J. 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.

¹Yang He,¹Xiao-Wen Liu,¹Ai-Cheng Zhang
Meteoritics & Planetary Science (in Press) Kink to Article [https://doi.org/10.1111/maps.13817]
¹State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, 210023 China
Published by arrangement with John Wiley & Sons

In this study, we report the petrography and mineralogy of a brecciated eucrite Northwest Africa (NWA) 8021, which shows a locally layered texture with one layer containing graphic clasts and Si,Ti-rich regions. The graphic clasts contain rod-like grains of silica phases, augite, K-feldspar, and Ca-phosphate minerals included in anorthite. Some of the clasts contain relatively coarse grains of quartz, K-feldspar, and augite, which are chemically different from the rod-like phases, indicating different origins. All of the augite grains in the graphic clasts have rare earth element (REE) concentrations higher than those in typical eucrites. The bulk Na2O+K2O contents of the graphic clasts are higher than typical eucrites. All of these chemical features indicate that the graphic clasts were probably derived from an evolved parent rock. Low-degree partial melting of the eucritic crust (<10%) is required to generate a melt equilibrated with the REE-rich rod-like pyroxene from the graphic clasts. The Si,Ti-rich regions contain high abundances of silica phases (~52 vol%) and ilmenite (~9 vol%), probably derived from an evolved Si,Ti-rich rock (dacite). The evolved components observed in NWA 8021 are different from other evolved components observed in howardites and indicate more diverse evolution in the eucrite parent body than previously thought.