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Topographic map of part of Jezero crater showing the slope direction of the crater floor and the landing ellipse of the Mars 2020 mission. Red lines are 50 m contours and colors correspond to topography (blue = low, green to yellow = moderate, red = high). Note that the crater floor preferentially slopes north to south, rather than east to west.
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On February 18, 2021 NASA's Perseverance rover landed in Jezero crater, located at the northwestern edge of the Isidis basin on Mars. The uppermost surface of the present‐day crater floor is dominated by a distinct geologic assemblage previously referred to as the dark‐toned floor. It consists of a smooth, dark‐toned unit overlying and variably cov...
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This is the first part of a two‐part paper. NASA's Mars 2020 Perseverance rover measured winds on the Jezero crater floor close to the delta of an ancient river. A mostly repeatable diurnal cycle was observed and presented two regimes: (a) a convective regime, from dawn to sunset, with average easterly to southeasterly winds, during which maximum w...
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... Over time at T4a, weaker, possibly sedimentary materials, are preferentially eroded and then transported out of the EBD by suspension of clay/silt-sized particles or during climate conditions favorable to efficient sand-sized grain saltation. A similar differential erosion hypothesis was proposed to explain the topography associated with the VF margins (Holm- Alwmark et al., 2021;Schon et al., 2012). For . ...
We reassessed several orbital topographic data sets for the Perseverance rover landing site at Jezero Crater, Mars to better understand its floor units. Tens‐of‐meters deep topographic anomalies occur in the volcanic floor of Jezero crater and are not a result of impact cratering. Eight km‐scale steep escarpment‐bounded depressions may be locations of paleotopographic highs that were embayed by the volcanic floor lava flows, forming inverted topography from either contemporaneous upward inflation of embaying lavas or later deep scour due to differential erosion over 10⁷⁻⁹ years. Five multi km‐scale shallow‐sloped depressions linked by channel‐like forms may record locations of buried paleolakes and channels that predate the volcanic floor units or a drained magma system. These results indicate Jezero experienced multiple closed‐basin or dry phases, allowing erosion of the crater floor and creation of topography, which provides new geologic context for the samples gathered by Perseverance.
... The Perseverance rover is currently exploring Jezero crater to search for signs of past life and characterize the climate and geology of ancient Mars. Jezero is a 45-km diameter complex impact crater situated in the Nili Planum region that formed sometime during the Early Noachian to Late Noachian (e.g., Holm-Alwmark et al., 2021). The original crater floor was covered by igneous rocks interpreted to be volcanic and/or intrusive followed by clastic sedimentary materials interpreted to be fluvio-deltaic in origin (Mangold et al., 2021). ...
A key objective of the Perseverance rover mission is to acquire samples of Martian rocks for future return to Earth. Eventual laboratory analyses of these samples would address key questions about the evolution of the Martian climate, interior, and habitability. Many such investigations would benefit greatly from samples of Martian bedrock that are oriented in absolute Martian geographic coordinates. However, the Mars 2020 mission was designed without a requirement for orienting the samples. Here we describe a methodology that we developed for orienting rover drill cores in the Martian geographic frame and its application to Perseverance's first 20 rock samples. To orient the cores, three angles were measured: the azimuth and hade of the core pointing vector (i.e., vector oriented along the core axis) and the core roll (i.e., the solid body angle of rotation around the pointing vector). We estimated the core pointing vector from the attitude of the rover's Coring Drill during drilling. To orient the core roll, we used oriented images of asymmetric markings on the bedrock surface acquired with the rover's Wide Angle Topographic Sensor for Operations and eNgineering (WATSON) camera. For most samples, these markings were in the form of natural features on the outcrop, while for four samples they were artificial ablation pits produced by the rover's SuperCam laser. These cores are the first geographically‐oriented (<2.7° 3σ total uncertainty) bedrock samples from another planetary body. This will enable a diversity of paleomagnetic, sedimentological, igneous, tectonic, and astrobiological studies on the returned samples.
... The Jezero western fan and associated deltaic deposits are estimated to be ∼3.5 billion years old and represent the youngest unit of the Jezero crater . The rover landing site is on the crater floor, made up of a series of units that underlie and are therefore older than the sedimentary deltaic deposits (Holm-Alwmark et al., 2021;. Orbital data indicate the widespread occurrence of minerals formed by the interaction of water with rocks in Jezero crater, such as phyllosilicate minerals, although there is a lack of orbital detection of sulfate phases in this location (Ehlmann & Edwards, 2014). ...
Sulfur plays a major role in martian geochemistry and sulfate minerals are important repositories of water. However, their hydration states on Mars are poorly constrained. Therefore, understanding the hydration and distribution of sulfate minerals on Mars is important for understanding its geologic, hydrologic, and atmospheric evolution as well as its habitability potential. NASA's Perseverance rover is currently exploring the Noachian‐age Jezero crater, which hosts a fan‐delta system associated with a paleolake. The crater floor includes two igneous units (the Séítah and Máaz formations), both of which contain evidence of later alteration by fluids including sulfate minerals. Results from the rover instruments Scanning Habitable Environments with Raman and Luminescence for Organics and Chemistry and Planetary Instrument for X‐ray Lithochemistry reveal the presence of a mix of crystalline and amorphous hydrated Mg‐sulfate minerals (both MgSO4·[3–5]H2O and possible MgSO4·H2O), and anhydrous Ca‐sulfate minerals. The sulfate phases within each outcrop may have formed from single or multiple episodes of water activity, although several depositional events seem likely for the different units in the crater floor. Textural and chemical evidence suggest that the sulfate minerals most likely precipitated from a low temperature sulfate‐rich fluid of moderate pH. The identification of approximately four waters puts a lower constraint on the hydration state of sulfate minerals in the shallow subsurface, which has implications for the martian hydrological budget. These sulfate minerals are key samples for future Mars sample return.
... Rocks of the Séítah formation show orbital and in situ detections of olivine and carbonate (Beyssac et al., 2023;Brown et al., 2020;Corpolongo et al., 2023;Liu et al., 2022;Rice et al., 2023;Wiens et al., 2022) that are similar to those observed within a regional olivine-carbonate unit that occurs across the Nili Fossae and Northeast Syrtis region (Brown et al., 2020;Kremer et al., 2019;Mandon et al., 2020;Scheller & Ehlmann, 2020), including within the Jezero crater watershed (Brown et al., 2020;Goudge et al., 2015;Horgan et al., 2020). The Máaz formation consists of a series of thinly layered, crater-retaining units that overlie, potentially with a significant unconformity, rocks of the Séítah formation and comprise the basis of the unit originally described as the dark-toned/volcanic floor unit (Holm-Alwmark et al., 2021;Stack et al., 2020). Orbital detections of the dark-toned floor unit show a variety of mafic lithologies, including detections of high-Ca pyroxene and sometimes olivine (Goudge et al., 2015;Horgan et al., 2020;Hundal et al., 2022), with mixed olivine-pyroxene detections correlating to regions that have higher thermal inertia (Horgan et al., 2020) and evidence for exposed outcrops. ...
During its first year of operation, the Perseverance rover explored the cratered and fractured floor of Jezero crater on Mars. Here, we report the use of the Scanning Habitability Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) imaging system that includes two high‐resolution cameras, the Autofocus and Contextual Imager (ACI) and Wide Angle Topographic Sensor for Operations and eNgineering (WATSON). ACI is a fixed focus gray scale imager with a resolution of 10.1 μm/pixel whereas WATSON is a variable field of view, variable focus imager capable of resolution down to 14 μm/pixel. WATSON is a reflight of the MArs Hand Lens Imager (MAHLI) imager and has similar capabilities. During first‐time activities, WATSON was used to support both science and engineering operations related to sample and abrasion patch assessment and sample collection and caching. WATSON also documented the deployment of the Ingenuity helicopter. The Crater Floor Campaign identified two primary rock units, the Máaz formation and the Séítah formation, which have been interpreted as lava flows and an olivine cumulate, respectively. Interpretation of rock textures with WATSON and ACI images was limited to abraded surfaces because unmodified outcrop surfaces (herein termed “natural surfaces”) show high degrees of dust covering, wind abrasion, and coating by secondary mineral products. WATSON and ACI images support the hypothesis that the material of both the Máaz and Séítah formations consists of largely aqueously altered mafic materials with varying igneous origins.
... The study of depositional systems on Mars started with orbital images, which provided evidence of sediment transport under both subaerial and subaqueous conditions in a variety of environments (Goudge et al., 2012(Goudge et al., , 2015Goudge and Fassett, 2018;Fassett and Goudge, 2021;Holm-Alwmark et al., 2021;Cardenas and Lamb, 2022). The Jezero crater was selected as the landing site for the 2020 Mars mission, due to the presence of two sedimentary fans along the western and northern margins of the crater (Fassett and Head, 2005;Ehlmann et al., 2008). ...
... The Maaz formation overlies the Seitah formation ("Séítah" is Navajo for "amidst the sands"), which is a layered and eroded landscape of ridges and sand that is interpreted as an olivine-dominated cumulate likely originating in a thick lava flow or lava lake that once filled the crater floor (Liu et al., 2022). The western delta and other sedimentary remnants in Jezero crater appear to overlie the Maaz formation (Holm- Alwmark et al., 2021), suggesting that some or all lacustrine activity post-dated emplacement of crater floor lavas. Geochronological analyses of these samples back on Earth may thus provide critical constraints on the timing of events in Jezero crater, including emplacement of the crater floor as well as potentially the onset of lake activity . ...
... The Maaz formation near the delta is largely obscured by thick regolith, but exhibits lobate margins similar to Artuby ridge and a surface texture similar to that observed south of Artuby ridge. In some locations, this area exhibits OPX absorptions in CRISM data similar to the delta top, and thus consistent with erosion from the delta or previously overlying sediments (Holm- Alwmark et al., 2021). However, the overall spectral signature in the area is most consistent with a mixture of OPX with CPX, which could suggest that the lower Maaz formation is the main substrate in the area. ...
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 would provide important constraints on the petrologic history, aqueous processes, and timing of key events in Jezero crater. However, interpreting these samples requires 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, Radar Imager for Mars' subsurface eXperiment 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 Máaz formation also has the potential to constrain processes such as fluvial activity inside Jezero crater. Various publications have proposed cases for the relative timing of deposition of the dominant geomorphologic units in the Perseverance vicinity (i.e., the western delta, Cf-fr, and Cf-f1), with scenarios presented for Cf-fr deposition before delta formation (B. H. N. Horgan et al., 2020;Holm-Alwmark et al., 2021;Ruff, 2017;Stack et al., 2020;Sun & Stack, 2020a), after a delta formation (Goudge et al., 2015;Schon et al., 2012;Stack et al., 2020), and interfingering delta/crater floor rocks (e.g., B. Horgan et al., 2022;Stack et al., 2020). ...
We present a combined geomorphologic, multispectral, and geochemical analysis of crater floor rocks in Jezero crater based on data obtained by the Mast Camera Zoom and SuperCam instruments onboard the NASA Mars 2020 Perseverance rover. The combined data from this analysis together with the results of a comparative study with geologic sites on Earth allows us to interpret the origins of rocks exposed along the Artuby ridge, a ∼900 m long scarp of lower Máaz formation rocks. The ridge exposes rocks belonging to two morphologically distinct members, Artuby and Rochette, both of which have basaltic composition and are spectrally indistinguishable in our analysis. Artuby rocks consist of morphologically distinct units that alternate over the ridge, bulbous, hummocky, layers with varying thicknesses that in places appear to have flowed over underlying strata, and sub‐planar thinner laterally continuous layers with variable friability. The Rochette member has a massive appearance with pronounced pitting and sub‐horizontal partings. Our findings are most consistent with a primary igneous emplacement as lava flows, through multiple eruptions, and we propose that the thin layers result either from preferential weathering, interbedded ash/tephra layers, ʻaʻā clinker layers, or aeolian deposition. Our analyses provide essential geologic context for the Máaz formation samples that will be returned to Earth and highlight the diversity and complexity of geologic processes on Mars not visible from orbit.
... By contrast, the Séítah formation appears to be composed of cumulate rocks dominated by olivine and some pyroxene (Liu et al., 2022;this study). At the time of writing, the structural relationship between these two formations and the Jezero delta is not yet established, but the current hypotheses suggest that they were emplaced before the formation of the delta (Farley et al., 2022;Holm-Alwmark et al., 2021;Quantin-Nataf et al., 2023). ...
... Based on geomorphic expression and mineralogy from orbital data, Goudge et al. (2015) mapped Séítah and its inferred equivalents (their "light-toned floor unit") as being exposed primarily to the outer edge of the crater floor while the central region is dominantly covered by the Máaz formation (their "volcanic floor unit"). Higher-resolution mapping (Holm- Alwmark et al., 2021;Stack et al., 2020) demonstrates that exposures of this formation in the region where Perseverance landed represent depositional or erosional inliers into the Máaz formation. Remarkably, in most areas, Séítah is generally topographically higher than the surrounding Máaz formation although it is stratigraphically older. ...
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.
... The leading pre-landing model (e.g., Goudge et al., 2015) for the sequence of events in Jezero crater was (a) the formation of the Isidis impact; (b) the formation of Jezero in the inner margin of Isidis basin; (c) the filling of Jezero crater by the regional olivine bearing unit at about 3.8 Ga (Mandon et al., 2020); (d) the emplacement of the delta and the marginal carbonate-bearing unit during one or more lacustrine phases; and (e) the emplacement of the unaltered mafic floor unit (Goudge et al., 2015). However, high resolution investigation of the stratigraphic relationships between the deltaic deposits and possible distal delta remnants and the dark crater floor unit questions this succession of events (Farley et al., 2022;Holm-Alwmark et al., 2021;Stack et al., 2020). In an alternative model, the deltaic deposits may overlie the floor unit, making the dark floor unit older than Jezero's fluvio-deltaic deposits (Holm- Alwmark et al., 2021). ...
... However, high resolution investigation of the stratigraphic relationships between the deltaic deposits and possible distal delta remnants and the dark crater floor unit questions this succession of events (Farley et al., 2022;Holm-Alwmark et al., 2021;Stack et al., 2020). In an alternative model, the deltaic deposits may overlie the floor unit, making the dark floor unit older than Jezero's fluvio-deltaic deposits (Holm- Alwmark et al., 2021). The stratigraphic relationship between the dark cratered floor unit and the delta is not so clear from orbital data analysis. ...
... The interpretation of the remnant deposit is from Stack et al. (2020) and Mangold et al. (2021). The stratigraphic relationships displayed in the legend are from Holm- Alwmark et al. (2021) who argued for a dark floor unit pre-dating the deltaic deposits. floor unit, Goudge et al. estimated its age to 3.45 Ga, thus placing the end of the lacustrine activity near the Noachian-Hesperian transition (Goudge et al., 2012). ...
During the first year of NASA's Mars 2020 mission, Perseverance rover has investigated the dark crater floor unit of Jezero crater and four samples of this unit have been collected. The focus of this paper is to assess the potential of these samples to calibrate the crater‐based Martian chronology. We first review the previous estimation of crater‐based model age of this unit. Then, we investigate the impact crater density distribution across the floor unit. It reveals that the crater density is heterogeneous from areas which have been exposed to the bombardment during the last 3 Ga to areas very recently exposed to bombardment. It suggests a complex history of exposure to impact cratering. We also display evidence of several remnants of deposits on the top of the dark floor unit across Jezero below which the dark floor unit may have been buried. We propose the following scenario of burying/exhumation: the dark floor unit would have been initially buried below a unit that was a few tens of meters thick. This unit then gradually eroded away due to Aeolian processes from the northeast to the west, resulting in uneven exposure to impact bombardment over 3 Ga. A cratering model reproducing this scenario confirms the feasibility of this hypothesis. Due to the complexity of its exposure history, the Jezero dark crater floor unit will require additional detailed analysis to understand how the Mars 2020 mission samples of the crater floor can be used to inform the Martian cratering chronology.
... If the Máaz formation is igneous, radioisotope analysis of datable minerals in a returned Máaz sample could derive an absolute age that can be compared to its crater count age estimates (Quantin-Nataf et al., 2021;Simon et al., 2023). The Máaz formation is also in contact with the Jezero western delta (Goudge et al., 2015;Holm-Alwmark et al., 2021;Stack et al., 2020) and therefore can help place constraints on the age of the western delta (otherwise dated to the Late Noachian or Hesperian; Fassett & Head, 2008;Mangold et al., 2020) and samples obtained from it Simon et al., 2023). Additional value of returned sample science on "in place" Máaz bedrock includes paleomagnetism analyses that could reveal information about the timing of planetary dynamo . ...
The Mars 2020 Perseverance rover landed in Jezero crater on 18 February 2021. After a 100‐sol period of commissioning and the Ingenuity Helicopter technology demonstration, Perseverance began its first science campaign to explore the enigmatic Jezero crater floor, whose igneous or sedimentary origins have been much debated in the scientific community. This paper describes the campaign plan developed to explore the crater floor's Máaz and Séítah formations and summarizes the results of the campaign between sols 100–379. By the end of the campaign, Perseverance had traversed more than 5 km, created seven abrasion patches, and sealed nine samples and a witness tube. Analysis of remote and proximity science observations show that the Máaz and Séítah formations are igneous in origin and composed of five and two geologic members, respectively. The Séítah formation represents the olivine‐rich cumulate formed from differentiation of a slowly cooling melt or magma body, and the Máaz formation likely represents a separate series of lava flows emplaced after Séítah. The Máaz and Séítah rocks also preserve evidence of multiple episodes of aqueous alteration in secondary minerals like carbonate, Fe/Mg phyllosilicates, sulfates, and perchlorate, and surficial coatings. Post‐emplacement processes tilted the rocks near the Máaz‐Séítah contact and substantial erosion modified the crater floor rocks to their present‐day expressions. Results from this crater floor campaign, including those obtained upon return of the collected samples, will help to build the geologic history of events that occurred in Jezero crater and provide time constraints on the formation of the Jezero delta.
