We analyze Kodiak, an eroded delta remnant in Jezero Crater, Mars, using several hundred images from the Mastcam-Z and SuperCam instruments on the Mars 2020 Perseverance Rover. We create a high-accuracy digital terrain model to measure Kodiak’s stratigraphic layers, which we divide into three units and characterize individually. While each unit possesses geometries interpreted as consistent with a Gilbert-style delta formation, the older units exposed on Kodiak’s north to northeast sides include more complex layered structures with azimuthally varying foresets. We compare Kodiak’s northeast foresets with the clinoforms of Whale Mountain, an outcrop exposed in the Western Jezero Delta scarp, and show similar azimuthally varying foresets. The stratigraphic analysis presented herein (strike and dip, unit thickness, etc.) will help test and refine detailed sedimentological hypotheses for the formation and evolution of the Jezero delta. Our 3D reconstruction and measurements enable unprecedented precision to evaluate depositional models and advance geological interpretation.

Ekta Aggarwala, Sanjeev Guptaa, Alexander C. Whittakera, Philippa Masona, Kartikeya S. Sangwana, Fritz Schluneggerba Imperial College London, b University of BernMajor flood events cause adverse impacts on human populations, infrastructure, and resources. The occurrence of flood events has led to much research on flood vulnerability, exposure, and post-disaster assessment. However, there has been a limited focus on studying the recovery of societies and how this varies among different socio-economic communities. Satellite datasets are an effective and cost-efficient way to analyze the spatial extent of flooding and its impact on anthropogenic activity in floodplains. Here we present an analysis of NASA Black Marble nighttime lights (NTL) data for the 2022 Indus River flood in Pakistan as it provides information on lit infrastructure which is a useful proxy for real-time monitoring of human presence. We investigate the impact of the flooding on the variance in NTL radiance during and after the event, to investigate human exposure and response to floods.The Black Marble daily NTL VNP46A2 data product is the daily moonlight-adjusted NTL. Here, we utilize this dataset to assess the spatial impact of the 2022 Indus River flooding, which was one of the biggest flood events in recent history affecting 33 million people. We focus on the downstream floodplains of the Indus basin because frequent flooding over this area is historically documented. To determine the spatial extent of flooding we use ESA Sentinel SAR data to map the spatial and temporal evolution of flood extent between June-September 2022. In tandem, we analyze NTL data to explore the variation in NTL radiance values over a similar timescale. In particular, we use the NTL to estimate the variation in its radiance for areas of high flood exposure. We find that the NTL radiance in the flooded areas was affected for approximately 13 weeks. It took approximately 10 weeks post-flooding for the area’s radiance to recover up to pre-flooding level. The mean radiance from pre-flood to during the main flood period shows a decline by a factor of 5. Additionally, there is varying exposure and recovery for different socio-economic communities in the area. Our findings have the potential to improve our understanding of human response to floods and vulnerability at the lowest administrative level in a fast, safe, and cost-effective manner. This may also provide a framework for policymakers to assess flood vulnerability and impact at a basin scale.

Early observations from the Perseverance rover suggested a deltaic origin for the western fan of Jezero crater only from images of the Kodiak butte. Here, we use images from the SuperCam Remote Micro-Imager and the Mastcam-Z camera to analyze the western fan front along the rover traverse, and further assess its depositional origin. Outcrops in the middle to lower half of hillslopes are composed of planar, inclined beds of sandstone that are interpreted as foresets of deltaic deposits. Foresets are locally structured in ~20-25 m thick, ~80-100 m long, antiformal structures interpreted as deltaic mouth bars. Above these foresets are observed interbedded sandstones and boulder conglomerates, interpreted as fluvial topset beds. One well-preserved lens of boulder conglomerate displays rounded clasts within well-sorted sediment deposited in fining upward beds. We interpret these deposits as resulting from lateral accretion within fluvial channels. Estimations of peak discharge rates give a range between ~100 and ~500 m3.s-1 consistent with moderate to high floods. By contrast, boulder conglomerates exposed in the uppermost part of hillslopes are poorly sorted and truncate underlying beds. The presence of these boulder deposits suggests that intense, sediment-laden flood episodes occurred after the deltaic foreset and topset beds were deposited, although the origin, timing, and relationship of these boulder deposits to the ancient lake that once filled Jezero crater remains undetermined. Overall, these observations confirm the deltaic nature of the fan front, and suggest a highly variable fluvial input.

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.

For ~ 500 sols, the Mars Science Laboratory team explored Vera Rubin ridge (VRR), a topographic feature on the northwest slope of Aeolis Mons. Here we review the sedimentary facies and stratigraphy observed during sols 1800-2300, covering more than 100 m of stratigraphic thickness. Curiosity’s traverse includes two transects across the ridge, which enables studies of lateral variability over a distance of ~ 300 m. Three informally named stratigraphic members of the Murray formation are described: Blunts Point, Pettegrove Point, and Jura, with the latter two forming the ridge. The Blunts Point member, exposed just below the ridge, is characterized by a recessive, fine-grained facies that exhibits extensive planar lamination and is crosscut by abundant curviplanar veins. The Pettegrove Point member is more resistant, fine-grained, thinly planar laminated, and contains a higher abundance of diagenetic concretions. Conformable above the Pettegrove Point member is the Jura member, which is also fine-grained and parallel stratified, but is marked by a distinct step in topography which coincides with meter-scale inclined strata, a thinly and thickly laminated facies, and occasional crystal molds. All members record low-energy lacustrine deposition, consistent with prior observations of the Murray formation. Uncommon outcrops of low-angle stratification suggest possible subaqueous currents, and steeply inclined beds may be the result of slumping. Collectively, the rocks exposed at VRR provide additional evidence for a long-lived lacustrine environment (in excess of 10^6 years via comparison to terrestrial records of sedimentation), which extends our understanding of the duration of habitable conditions in Gale crater.

Oxia Planum, the landing site for the ExoMars rover mission, is a shallow basin on the southern margin of Chryse Planitia that hosts remnants of sediment fans associated with the ancient channel system Coogoon Vallis. This indicates runoff from a catchment in Arabia Terra has transported material into the landing site. To explore this fluvial system we created a model catchment for Oxia Planum and, using 6 m/pixel ConTeXt camera (CTX) orbital remote sensing image data, we digitised the fluvial and lacustrine landforms in Western Arabia Terra in and around this catchment. We find: (1) The catchment has a minimum area of ~2.1×105 km2 and has been episodically deformed by tectonic activity; (2) There were at least two phases of fluvial activity. The first created a mature landscape associated with Coogoon Vallis, which may have deposited alluvial or deltaic deposits in the Oxia Basin. After a substantial hiatus, a second phase of activity incised u-section channels into the pre-existing landscape and channel systems; and (3) Evidence for numerous possible paleolake deposits within the catchment. These are not well connected to the fluvial system and were probably sustained by ground water activity contemporaneous with both phases of fluvial activity. This groundwater might have modified the geochemistry of Oxia Planum. Oxia Planum probably experienced an alluvial or distal deltaic/lacustrine depositional environment during the mid Noachian, which was later overprinted by a younger phase of fluvial activity.

The NASA Mars 2020 Perseverance rover mission will collect a suite of scientifically compelling samples for return to Earth. On the basis of orbital data, the Mars 2020 science team* identified two notional sample caches to study (1) the geology of Jezero crater, collected during the prime mission and (2) the ancient crust outside of Jezero crater, collected during a possible extended mission. Jezero crater geology consists of well-preserved, Early Hesperian to Late Noachian deltaic and lacustrine deposits sourced from a river system that drained Noachian terrain. The crater floor comprises at least two distinct units of sedimentary or volcanic origin whose relationship to the deltaic deposits is presently unclear. Remotely-sensed data reveal signatures of carbonate+olivine and clay minerals within crater floor and crater margin units. Samples from within Jezero that comprise the prime mission notional sample collection thus include: crater floor units; fine- and coarse-grained delta facies, the former with potential to preserve organic matter and/or biosignatures, the latter to possibly constrain the type and timing of sediment deposition; chemical sediments with the potential to preserve biosignatures; a sample of crater rim bedrock; and at least one sample of regolith. The region of southern Nili Planum, directly outside the western rim of Jezero crater, is geologically distinct from Jezero crater and contains diverse Early or even Pre-Noachian lithologies, that may contain records of early planetary differentiation, magnetism, paleoclimate and habitability. The notional sample collection from this region will include: layered and other basement rocks; megabreccias, which may represent blocks of (pre-)Noachian crust; basement-hosted hydrothermal fracture fill; olivine+carbonate rocks that are regionally significant and may be related to units within Jezero crater; and mafic cap unit rocks. The samples described are notional and may change with ongoing surface investigations. However, the samples we anticipate collecting align well with community priorities for Mars exploration, addressing geologic diversity, potential ancient biologic activity on Mars, planetary evolution, volatiles, and human health hazards. *Many other Mars 2020 team members were involved in this planning