¹M.S.Rice et al. (>10)
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2022JE007548]
¹Western Washington Univ, Bellingham, WA, United States
Published by arrangement with John Wiley & Sons

NASA’s Mars-2020 Perseverance rover spent its first year in Jezero crater studying the mafic lava flows of the Máaz formation and the ultramafic cumulates of the Séítah formation, both of which have undergone minor alteration and are variably covered by coatings, dust and/or soil deposits. Documenting the rock and soil characteristics across the crater floor is critical for establishing the geologic context of Perseverance’s cached samples – which will eventually be returned to Earth – and for interpreting the deposition and modification of the Máaz and Séítah formations. Mastcam-Z, a pair of multispectral, stereoscopic zoom-lens cameras, provides broadband red/green/blue and narrowband visible to near-infrared images (VNIR, 440-1020 nm). From multipsectral observations from sols 0-380, we compiled a database of ∼2400 representative Mastcam-Z spectra. We analyzed principal components, spectral parameters and laboratory spectra of pure minerals and natural rock surfaces to interpret the spectral diversity of rocks and soils. We define eight spectral classes of rocks: Dusty, Hematite-like, Coated, Low-Ca Pyroxene-like, Olivine-like, Weathered Olivine-like, Fe-rich Pyroxene-like, and Dark Oxide-like. The variability of soil spectra in the Jezero crater floor is controlled primarily by the amount of dust and indicates a largely consistent soil mineralogy across the traverse, with the exception of the area disturbed by the landing event. In comparison to rock spectra from the Curiosity rover’s Mastcam instrument in Gale crater, rocks on the Jezero crater floor are generally less spectrally diverse, but the Olivine-like rocks within the Séítah formation represent new spectral classes in Mars surface exploration.

¹Yoko Kebukawa et al. (>10)
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115582]
Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
Copyright Elsevier

Primitive carbonaceous xenolithic clasts found in sturdy metamorphosed meteorites often provide opportunities to reach labile volatile-rich materials which are easily destroyed during atmospheric entry and materials which we do not have sampled as individual meteorites. Among them, a xenolithic carbonaceous clast in the Zag H3–6 ordinary chondrite has been providing us with the opportunity to analyze a possible sample from D/P-type asteroids. Here we performed a new suite of coordinated analyses of organic matter in the Zag clast using the atomic force microscope infrared spectroscopy (AFM-IR) combined with nanoscale secondary ion mass spectrometer (NanoSIMS), X-ray absorption near-edge spectroscopy (XANES) coupled with scanning transmission X-ray macroscope (STXM), Raman, and (scanning) transmission electron microscopy [(S)TEM] on adjacent ultramicrotomed thin sections from a single sample grain. We successfully demonstrated the practicality of coordinated analyses using AFM-IR, Raman and NanoSIMS on the same sample area, as well as STXM/XANES on adjacent (and nearly identical) thin sections to those used for AFM-IR. The AFM-IR map and STXM maps provided consistent and complementary results. We found that at least two types of organics were closely mixed in this specimen. One was deuterium-rich, Cdouble bondO rich organics with likely smaller aromatic domains, possibly originating in relatively oxidized environments from D-rich precursors. The other type was less deuterium-rich, but aromatic-rich organics, possibly produced in relatively reduced and higher temperature environments with less deuterium-rich precursors. These characteristics point to complex mixtures of materials with different origins and sampling a wide heliocentric range of the Solar System before accretion in the parent body of the clast.