The first samples collected by the Perseverance rover on the Mars 2020 mission were from the Maaz formation, a lava plain that covers most of the floor of Jezero crater. Laboratory analysis of these samples back on Earth will provide important constraints on the petrologic history, aqueous processes, and timing of key events in Jezero. However, interpreting these samples will require a detailed understanding of the emplacement and modification history of the Maaz formation. Here we synthesize rover and orbital remote sensing data to link outcrop-scale interpretations to the broader history of the crater, including Mastcam-Z mosaics and multispectral images, SuperCam chemistry and reflectance point spectra, RIMFAX ground penetrating radar, and orbital hyperspectral reflectance and high-resolution images. We show that the Maaz formation is composed of a series of distinct members corresponding to basaltic to basaltic andesite lava flows. The members exhibit variable spectral signatures dominated by high-Ca pyroxene, Fe-bearing feldspar, and hematite, which can be tied directly to igneous grains and altered matrix in abrasion patches. Spectral variations correlate with morphological variations, from recessive layers that produce a regolith lag in lower Maaz, to weathered polygonally fractured paleosurfaces and crater-retaining massive blocky hummocks in upper Maaz. The Maaz members were likely separated by one or more extended periods of time, and were subjected to variable erosion, burial, exhumation, weathering, and tectonic modification. The two unique samples from the Maaz formation are representative of this diversity, and together will provide an important geochronological framework for the history of Jezero crater.

The SuperCam instrument onboard Perseverance rover has remote imaging (RMI), VISIR, LIBS, Raman and Time-Resolved Luminescence (TRL) capabilities. RMI images of the rocks at the Octavia Butler landing site have revealed important granular texture diversities. VISIR raster point observations have revealed important differences in the 2.10-2.50 µm infrared range (metal-hydroxides); many include water features at 1.40±0.04 and 1.92±0.02 µm [1]. LIBS observations on the same points analyzed by VISIR revealed important differences in the concentrations of major elements, suggesting mineral grain sizes larger than the laser beam (300-500 µm). LIBS and VISIR show coherent results in some rock surfaces that are consistent with an oxy-hydroxide (e.g., ferrihydrite) [1]. LIBS elemental compositions are consistent with pyroxenes, feldspars, and more often feldspar-like glass, often enriched in silica. Olivine compositions [1, 2] have been observed so far in LIBS data (up to Sol 140) exclusively in rounded regolith pebbles. They have not yet been observed in the rocks themselves, which are MgO-poor compared to regolith and are consistent with FeO bearing pyroxenes (e.g., hedenbergite, ferrosilite). A 3x3 LIBS and VISIR raster (9x9 mm) acquired on a low-standing rock on sol 90 exemplifies these finding. A dark L-shaped filled void sampled by points 1 and 2 with possible ferrihydrite (H seen in LIBS and VISIR spectra). Point 5 contains abundant silica and alkali elements but is Al-depleted relative to feldspars, consistent with dacitic glass composition. Point 7 has TiO2 content consistent with ilmenite. Comparisons to (igneous) Martian meteorites are potentially useful, e.g. [3], to explain the presence of several minerals, although most Martian meteorites are olivine-rich, e.g., more mafic than the rocks at the landing site. In summary, the bedrock at Octavia Butler landing site can be interpreted as showing evidence for relatively coarse-grained weathered pyroxenes, iron and titanium oxides and feldspars, while the local soil contains pebbles from a different source (richer in MgO) incorporating olivine grains. References: [1] Mandon et al. 2021 Fall AGU, New Orleans, LA, 13-17 Dec. ; [2] Beyssac et al. 2021 Fall AGU, New Orleans, LA, 13-17 Dec. ; [3] Garcia-Florentino et al.(2021), Talanta, 224, 121863.

The Mars Environmental Dynamics Analyzer (MEDA) on board Perseverance includes first-of-their-kind sensors measuring the incident and reflected solar flux, the downwelling atmospheric IR flux, and the upwelling IR flux emitted by the surface. We use these measurements for the first 350 sols of the Mars 2020 mission (Ls ~ 6-174 deg; in Martian Year 36) to determine the surface radiative budget on Mars, and to calculate the broadband albedo (0.3-3 μm) as a function of the illumination and viewing geometry. Together with MEDA measurements of ground temperature, we calculate the thermal inertia for homogeneous terrains without the need for numerical models. We found that: (1) the observed downwelling atmospheric IR flux is significantly lower than model predictions. This is likely caused by the strong diurnal variation in aerosol opacity measured by MEDA, which is not accounted for by numerical models. (2) The albedo presents a marked non-Lambertian behavior, with lowest values near noon and highest values corresponding to low phase angles (i.e., Sun behind the observer). (3) Thermal inertia values ranged between 180 (sand dune) and 605 (bedrock-dominated material) SI units. (4) Averages across Perseverance’ traverse of albedo and thermal inertia (spatial resolution of ~3-4 m2) are in very good agreement with collocated retrievals of thermal inertia from THEMIS (spatial resolution of 100 m per pixel) and of bolometric albedo in the 0.25-2.9 μm range from (spatial resolution of ~300 km2). The results presented here are important to validate model predictions and provide ground-truth to orbital measurements.

The Perseverance rover, Mars 2020 mission, landed on the surface of the Jezero Crater, on February, 18th 2021. This Martian crater is suspected to have hosted a paleolake as evidenced by the numerous detections of aqueously-altered phases and thus is a promising candidate for the search for past Martian life. The SuperCam instrument, elaborated by a consortium of American and European laboratories, plays a leading role in this investigation thanks to its highly versatile payload providing rapid, synergistic, fine-scale mineralogy, chemistry, and color imaging. After its landing, the first measurements of Martian targets with the infrared spectrometer of SuperCam (IRS) showed new instrumental behaviors that had to be characterized and calibrated to derive unbiased science data. The IRS radiometric response has thus been calibrated using periodic observations of the Aluwhite SuperCam Calibration Target (SCCT). Parasitic effects were understood and mitigated, and the instrumental dark and noise are characterized and modeled. The reflectance calibrated data products, provided periodically on the NASA Planetary Data System, are corrected from the main instrumental features.

We examine the observed properties of the Nili Fossae olivine-clay-carbonate lithology from orbital data and in situ by the Mars 2020 rover at the Séítah unit in Jezero crater, including: 1) composition (Liu, 2022) 2) grain size (Tice, 2022) 3) inferred viscosity (calculated based on geochemistry collected by SuperCam (Wiens, 2022)). Based on the low viscosity and distribution of the unit we postulate a flood lava origin for the olivine-clay-carbonate at Séítah. We include a new CRISM map of the clay 2.38 μm band and use in situ data to show that the clay in the olivine cumulate in the Séítah formation is consistent with talc or serpentine from Mars 2020 SuperCam LIBS and VISIR and MastCam-Z observations. We discuss two intertwining aspects of the history of the lithology: 1) the emplacement and properties of the cumulate layer within a lava lake, based on terrestrial analogs in the Pilbara, Western Australia, and using previously published models of flood lavas and lava lakes, and 2) the limited extent of post emplacement alteration, including clay and carbonate alteration (Clave, this issue; Mandon, this issue).

Perseverance landed at the Octavia E. Butler landing site next to the Séítah dune region in Jezero crater on 18 February 2021, in close proximity to the largest exposed carbonate deposit on Mars. These carbonate signatures have been shown to be associated with the strongest olivine signatures at Jezero crater (Goudge+ 2015, Brown+ 2020). Alteration of olivine can lead to carbonate+H2 production, an energy source for microbes (Mayhew+, 2013). The question of the origin of the olivine-carbonate unit represents both an opportunity and a challenge for the rover mission and future sample return efforts. Carbonate The landing site is not near the region of carbonate detections (Figure 1), however the rover’s westward traverse will take us over the carbonates on approach to the crater rim. No reliable indications of the 2.5 μm carbonate band have yet been convincingly detected by the SCAM VISIR instrument. Olivine Studies of the olivine-carbonate unit concluded the olivine is relatively Fe-rich and coarse grained (mm: Poulet+ 2007, Clenet+ 2013). The strongest in-situ olivine signatures are found in dune material analysed by LIBS/VISIR (Beyssac+ Mandon+ this conf). This grain size characterization work may be used to investigate the interaction of olivine with water and CO2 (Escamilla-Roa+ 2020). These surface-gas processes are enhanced when olivine is in fine grain form. Ash dispersal modeling is ongoing (Ravanis+ this conf) to determine the range different sized ash particles could have traveled on ancient Mars. We cannot directly compare the 1 μm band for CRISM and VISIR, so we developed a new method that measures the curvature of three points on the absorption bands to assess their relative Fo# shifts and applied it to both datasets. Lab spectroscopy will be used to assess spectral variations with composition versus grain size. Two key factors driving the Fo# are mantle composition and melt temperature. Brown+ (2020) estimated a range of Fo44-65 for the most redshifted olivine observed by CRISM. McGetchin+Smythe (1978) showed that an Fe-rich mantle composition would produce highly viscous lavas and suggested an upper bound of Fo70 for olivine. Understanding the astrobiological potential of the olivine-carbonate unit is a priority of M2020 (Farley+ 2020) and we will speculate on potential formation models in this contribution.