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A. Udry

Publications and source records attributed to A. Udry.

Key Perseverance Sampling Locations for the Ancient Martian Crust and Implications for Mars Science

Since Feb 2021, the Perseverance rover has collected samples in the Jezero crater. The plan baselined at the 2018 landing site selection, subsequently further developed by the Mars-2020 team, and presented to the Decadal Survey included the exploration and sampling of the Jezero crater rim and the Nili Planum area, a rock record that is important to preserving the science return of the endeavor. Specifically, the science team identified the following prioritized science objectives aligned with community objectives that are not covered by the current sample cache: 1) Investigate the habitable environments with potential biosignatures from a more ancient time interval and from a diverse set of geological environments (incl. exposed subsurface) than the Jezero crater sedimentary deposits (Fig. 2). (2) Determine radioisotopic ages for well-defined craterretaining surfaces and/or the Isidis basin impact event. (3) Characterize ancient aqueous environments to study climate, environmental transitions, and habitability on ancient Mars. (4) Investigate planetary accretion, crustal evolution, and dynamo activity through analysis and sampling of igneous lithologies. (5) Study the geology of basin-forming impacts. In addition, for the Jezero rim and any Jezero ejecta: (6) Analyze Jezero impactites for potentially habitable hydrothermal environments and radioisotopic dating of the Jezero crater formation. From 2018 to now, we used a combination of High Resolution Imaging Experiment (HiRISE) and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data to further characterize Jezero rim and Nili Planum, culminating in our prioritized sample location recommendations: (1) Monument Valley and (2) Northwest Jezero rim.

Mars sample return↗

Petrological Traverse of the Olivine Cumulate Séítah Formation at Jezero Crater, Mars: A Perspective From SuperCam Onboard Perseverance

Séítah is the stratigraphically lowest formation visited by Perseverance in the Jezero crater floor. We present the data obtained by SuperCam: texture by imagery, chemistry by Laser-Induced Breakdown Spectroscopy, and mineralogy by Supercam Visible and Infrared reflectance and Raman spectroscopy. The Séítah formation consists of igneous, weakly altered rocks dominated by millimeter-sized grains of olivine with the presence of low-Ca and high-Ca pyroxenes, and other primary minerals (e.g., plagioclase, Cr-Fe-Ti oxides, phosphates). Along a ∼140 m long section in Séítah, SuperCam analyses showed evidence of geochemical and mineralogical variations, from the contact with the overlying Máaz formation, going deeper in the formation. Bulk rock and olivine Mg#, grain size, olivine content increase gradually further from the contact. Along the section, olivine Mg# is not in equilibrium with the bulk rock Mg#, indicating local olivine accumulation. These observations are consistent with Séítah being the deep ultramafic member of a cumulate series derived from the fractional crystallization and slow cooling of the parent magma at depth. Possible magmatic processes and exhumation mechanisms of Séítah are discussed. Séítah rocks show some affinity with some rocks at Gusev crater, and with some Martian meteorites suggesting that such rocks are not rare on the surface of Mars. Séítah is part of the Nili Fossae regional olivine-carbonate unit observed from orbit. Future exploration of Perseverance on the rim and outside of the crater will help determine if the observations from the crater floor can be extrapolated to the whole unit or if this unit is composed of distinct sub-units with various origins.

Mars 2020↗

An olivine cumulate outcrop on the floor of Jezero crater, Mars

The geological units on the floor of Jezero crater, Mars, are part of a wider regional stratigraphy of olivine-rich rocks, which extends well beyond the crater. We investigate the petrology of olivine and carbonate-bearing rocks of the Séítah formation in the floor of Jezero. Using multispectral images and x-ray fluorescence data, acquired by the Perseverance rover, we performed a petrographic analysis of the Bastide and Brac outcrops within this unit. We find that these outcrops are composed of igneous rock, moderately altered by aqueous fluid. The igneous rocks are mainly made of coarse-grained olivine, similar to some Martian meteorites. We interpret them as an olivine cumulate, formed by settling and enrichment of olivine through multi-stage cooling of a thick magma body.

Mars↗

Sampling of Jezero Crater Máaz Formation By Mars 2020 Perseverance Rover

Collection of samples that could be returned to Earth from the floor of Jezero crater is a major goal of the Mars 2020 mission. Laboratory analyses of these will expand exploration of Jezero, a Noachian crater on Mars characterized by a delta–lake system with high potential for habitability. The samples will also be used to test current ideas about the early planetary evolution of Mars. The Perseverance rover has collected samples from two members of the Máaz formation, mapped in orbital images as the Crater floor fractured rough unit by [1]. Type localities of the Roubion and Rochette members have been targeted and abraded prior to sample collection. Here we summarize these sampling activities and the potential of sampling the Chal member of Máaz. A similar summary for samples collected from the Séítah formation is described in Hickman-Lewis et al. (this meeting).

Mars 2020↗

Mars Sample Return Science Planning Group Phase 2 (MSPG2): Overview & Interim Report

Mars Sample Return (MSR) has been a high priority of the international planetary science community for decades. In recent years, significant programmatic advances have brought MSR closer to becoming a reality. In 2018, NASA and the European Space Agency (ESA) signed a joint Statement of Intent to continue defining respective roles and responsibilities in the flight missions required to realize MSR. In October 2020, NASA and ESA formalized this partnership with the signature of a Memorandum of Understanding for the MSR flight elements. The MSR campaign consists of M2020, two MSR flight elements and the ground-based infrastructure to receive, handle and curate the samples from Mars. In an engineering sense, MSR consists of a linked set of missions, and a concluding set of ground-based activities, that we refer to as the MSR Campaign.

G. Kminek↗

A Komatiite Succession as an Analog for the Olivine Bearing Rocks at Jezero

The Mars 2020 rover landed at Jezero crater on February 18, 2021 [1]. Since then, the rover has traveled around the “Séítah” region [2] and has collected data from the Mastcam-Z, Supercam, PIXL and SHERLOC instruments that has led to insights into the formation of the olivine-clay-carbonate bearing rocks that were identified from orbit [3,4]. Here we discuss three questions: 1) What have we learned about the olivine-claycarbonate unit? 2) What terrestrial analogs exist for the unit? 3) Why do the rocks have a thinly layered morphology? We shall briefly mention instrumental measurements which provide important information regarding the olivine bearing rock at Seitah. Note: Extended abstract included on attachment.

A.J. Brown↗

Composition and Density Stratification Observed by SuperCam in the First 300 Sols in Jezero Crater

The Perseverance rover has traveled > 2.5 km since leaving its Octavia Butler landing site in Jezero crater ~300 sols ago. The SuperCam remote sensing instrument suite has made > 1000 observations of bedrock along the traverse to provide a comprehensive picture of Jezero crater floor’s chemistry and mineralogy. SuperCam combines high resolution imaging, visible and near-infrared (VISIR) reflectance spectroscopy (0.4-0.85, 1.3-2.6 µm), remote time-resolved green-laser Raman and fluorescence spectroscopy, laser-induced breakdown spectroscopy (LIBS), and acoustic sensing into a single co-boresighted package [1, 2]. Derivation of the major element abundances as oxide wt% for this part of the mission is presented in [3], while calibration of the VIS and IR spectrometers are given in [4-7].

R.C. Wiens↗

Overview of the Bedrock Geochemistry and Mineralogy Observed By Supercam During Perseverance’S Delta Front Campaign

In February 2021, the Perseverance rover landed in Jezero crater, Mars. The crater floor was found to be composed of lava flows and cumulate rocks. These magmatic rocks appear to have undergone some limited aqueous alteration; however, it is not clear whether this alteration is related to the lacustrine phase of the crater. After completing its exploration of the crater floor, Perseverance reached the foot of the Jezero western fan in late April 2022 (sol ~422). Long-distance images acquired earlier in the mission had already confirmed the deltaic nature of the fan, which had long been suspected from orbital observations. Between April and December 2022, Perseverance investigated the basal layers of the delta at two locations named Hawksbill Gap and Cape Nukshak, which are ~400 m apart. Here, we present an overview of the geochemistry and mineralogy of the delta rocks as observed by SuperCam and show that these rocks record a diversity of past aqueous alteration environments.

E. Dehouck↗

Quantitative 3D Textural and Petrofabric Analysis of the Northwest Africa 10645 Nakhlite Using X-Ray Computed Tomography

Martian meteorites are currently the only samples available from Mars to study and are critical for elucidating variability in martian igneous processes over time [e.g., 1]. Quantifying igneous textures and fabrics can help us understand how rocks are formed and emplaced [e.g., 2]. These features are innately three dimensional (3D) and are often strongly heterogeneous in cumulate rocks, like the nakhlites and poikilitic shergottites [2–3], where there can be substantial textural variations between and within individual samples. However, most quantitative textural and fabric analyses on these samples have been limited to two dimensions through measurements made on polished petrographic thin sections. Thus, 3D petrographic measurements are imperative for both representative sample characterization and accurately interpreting magmatic processes. The emplacement of martian meteorites at or near the surface of Mars (i.e., extrusive or intrusive, respectively) remains enigmatic due to the innate lack of geologic context [e.g., 1], but conducting 3D quantitative textural and fabric analyses can help elucidate emplacement mechanisms and settings on Mars.

S. Ramsey↗

Mineral composition of Al-rich float rocks in Jezero crater as seen by Super-Cam

During its traverse across the Jezero crater floor and western fan, the Perseverance rover encountered > 4000 float rocks – of variable size (up to ~ 50 cm) scattered on the ground without apparent connection to the surrounding stratigraphy [1]. Analysis performed using the SuperCam instrument’s [2,3,4], Laser Induced Breakdown Spectroscopy (LIBS) revealed a high concentration of Al 2 O 3 , Cr, Ti and Ni [5], and very low of Fe, Mg, Ca and Na [5, 1]. SuperCam’s infrared reflectance spectroscopy (IRS, between 1.3 and 2.6 μm) showed the presence of Al-rich aqueous alteration minerals (characteristic absorption bands of kaolinite and Al-smectites at 1.4 and 2.2 μm) as well as some (likely Cr-) spinels, identified uthrough their broad asymmetric 2 μm band, responsible for the concavity of IR spectra. These mineral species alone do not fully account for the spectral shapes; hence, the objective is to further investigate spectral modeling to determine the most probable mineral assemblages. Here, we present the results of modeling 17 light-toned float rocks, up to Sol 924, complementary to [1].

C. Royer↗