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B P Weiss

Publications and source records attributed to B P Weiss.

7 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

Sampling the Margin Unit of Jezero Crater, Mars for Future Mars Sample Return

Mars 2020 Perseverance rover is currently exploring Jezero crater, which contains an ancient lake-delta system with a high potential for past habitability. One of Perseverance’s primary science goals is to collect a set of scientifically return-worthy samples for return to Earth (Mars Sample Return; MSR). Between February 2021 and December 2023, Perseverance has sealed 23 tubes containing 20 rock cores, 2 regolith samples and one atmosphere sample. All rock and regolith samples are accompanied by a set of observations (Sample Threshold Observation Protocol, the STOP List) performed on abrasion patches or regolith near each sample collection site. These observations are documented in the Initial Reports and the Sample Dossier (https://pds-geosciences.wustl.edu/missions/mars2020/returned_sample_science.htm). Here we provide an overview of the samples collected during the Margin campaign. The Margin unit is situated interior and adjacent to the western crater rim and exhibits a strong carbonate signal from orbital reflectance spectroscopy. Stratigraphically the unit lies beneath the previously explored curvilinear and blocky units of the fan top and is therefore older than those units. Based on its position near the crater rim and the strong carbonate detections it has been proposed to be a shoreline deposit with possible lacustrine carbonates. Alternative hypotheses include pyroclastic, fluviolacustrine and aeolian deposits. Based on rover observations a lacustrine shoreline deposit seems most likely. The planning of the Margin campaign took place during the summer of 2023, and 3-5 samples were baselined to be collected. Exploration of the Margin unit began in September 2023 and so far, two samples have been collected: the Pelican Point core at the Hans Amundsen Memorial Workspace in the Mandu Wall region , and the Lefroy Bay core at Lake Newell in the Turquoise Bay region (Fig. 1). The associated abrasion patches are Amherst Point (Pelican Point) and Bills Bay (Lefroy Bay) . Mandu Wall is interpreted to be stratigraphically lower than Turquoise Bay based on topography.

Mars sample return↗
NASA NTRS2024

Going With the Flow: Sedimentary Evolution of the Jezero Western Fan, Mars

Sedimentary fans developed at the mouths of Martian valleys have been interpreted as the deposits of sustained surface water flow on early Mars building either fluvial fan systems or deltas into standing bodies of water. Whilst much insight has been gleaned from orbital observations, it is only possible to constrain the character, relative timing and persistence of ancient aqueous activity on Mars through detailed on-the-ground interrogation of sedimentary successions built during fan growth. A prominent sedimentary fan deposit at the western margin of Jezero crater – the Western fan – has been interpreted from orbital data/observations to be a river delta that prograded into an ancient lake basin during the Late Noachian-Early Hesperian epochs on Mars (~3.6-3.8 Ga). The Western fan deposit forms a point-sourced depositional system developed at the mouth of Neretva Vallis, a valley system that is incised across the crater rim and has an extensive extra-crater catchment draining over diverse ancient geological units in Nili Planum. The mechanism of crater rim breaching remains unconstrained. Between 2022 and 2023, the Mars 2020 Perseverance rover explored the Western fan, with the objective of characterizing its paleoenvironmental context and collecting a diverse suite of sedimentary rock samples for return to Earth via the Mars Sample Return mission. Perseverance has now completed her traverse across the Western fan having commenced in the distal downstream sectors exposed at the erosional front of the fan and then crossing across its upper exposed surface toward the fan apex region near the mouth of Neretva Vallis. This transect provides a unique window into a Martian sediment routing system at a time when climate conditions permitted the flow of surface water. In this contribution, we review the overall sedimentary architecture of the fan and develop a model for its evolution based on detailed mapping of lithofacies changes across the fan. A first-order synoptic overview is presented.

Mars 2020↗
NASA NTRS2023

The Complex Exhumation History of Jezero Crater Floor Unit and Its Implication for Mars Sample Return

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.

Mars 2020↗
NASA NTRSDate not supplied

Astrobiological Potential of Rocks Acquired By the Perseverance Rover in Jezero Crater, Mars

The scientific community has prioritized the return of Martian rock samples with known geologic context for more than a decade (Beatty et al., 2019). Thus, the main objectives of the Perseverance rover mission on Mars include identifying past habitable environments, collecting rocks that are likely to preserve biosignaturesand using the rover’s instruments to look for potential biosignatures in these rocks (Farley et al., 2020). Here, we present an overview of the bedrock samples collected bythe Perseverance rover in Jezero crater to date and discuss the potential of the sampled materials to address astrobiological questions upon sample return to Earth.

Mars 2020↗
NASA NTRSDate not supplied

The Scientific Significance of Potential Samples From the Jezero Crater Rim

The Mars 2020 Perseverance rover has been exploring Jezero crater, Mars to characterize the geology,assess the potential for rocks to represent ancient habitable environments and/or preserve biosignatures, and collect a suite of scientifically compelling samples for return to Earth (Farleyet al.,2020).Thus far, Perseverance has collected samples that represent the diversity of igneous materials encountered on the crater floor and a suite of aqueously deposited sedimentary rocks from the fanand margin units(Simon et al., 2023; Bosak et al., 2024). When the rover ascendsthe crater rimit will encounter rocktypesthat are not included in the current sample cache. These include rocks fromthe Noachian whose mineralogical, geochemical, and geochronological recordswould greatly expand our understanding of early Mars. Some of the exposures are understood to come from subsurface aquifers that may represent the most ancient potentially habitablesubsurfaceenvironmentson Mars(Ehlmann et al., 2024). Samples ofthese rocks will add uniquescientific value tothe sample cache and to the Mars sample returnprogramby addressing outstanding questions in Mars science including potential habitability and how the climate and the interior of the planet evolved through time.

Mars 2020↗