¹L. M. Thompson,¹J. G. Spray,¹C. O’Connell-Cooper,²J. A. Berger,³A. Yen,⁴R. Gellert,⁴N. Boyd,⁴M. A. McCraig,⁵S. J. VanBommel
Journal of Geophysical Research (Planets) (in Press) Link to Article [https://doi.org/10.1029/2021JE007178]
¹Planetary and Space Science Centre, University of New Brunswick, Fredericton, Canada
²NASA Johnson Space Center, Houston, USA
³Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA
⁴Department of Physics, University of Guelph, Ontario, Canada
⁵Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, USA
Published by arrangement with John Wiley & Sons

Chemical data acquired by Curiosity’s Alpha Particle X-ray Spectrometer (APXS) during examination of the contact between the upper Mount Sharp group and overlying Stimson formation sandstones at the Greenheugh pediment reveal compositional similarities to rocks encountered earlier in the mission. Mount Sharp group strata encountered below the Basal Siccar Point group unconformity at the base and top of the section, separated by >300 m in elevation, have distinct and related compositions. This indicates enhanced post-depositional fluid flow and alteration focused along this contact. Sandstone targets exposed immediately above the unconformity have basaltic compositions consistent with previously encountered eolian Stimson formation sandstones, except at the contact, where they show the addition of S. Resistant sandstone outcrops above the contact have higher K, Mn and Na and lower Ni concentrations that primarily reflect changes in provenance. They are compositionally related to cap rock float blocks encountered as Curiosity climbed through the Mount Sharp group, and Bradbury group sandstone outcrops. The higher K, pediment sandstones are interpreted to have a similar provenance to some Bradbury group sandstones, further evidence for widespread, alkaline source rock within and/or in the vicinity of Gale crater. The Bradbury and Siccar Point groups may both be younger than the Mount Sharp group. Alternatively, an alkaline source area in and around Gale crater has been eroded by both water and wind at different times (both before and after deposition of the Mount Sharp group), during the evolution of the crater and its infill.

¹Levent Karacasulu,²David Karl,²Aleksander Gurlo,¹Cekdar Vakifahmetoglu
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2022.115270]
¹Department of Materials Science and Engineering, Izmir Institute of Technology, Urla, 35430 Izmir, Turkey
²Technische Universitaet Berlin, Institute of Materials Science and Technology, Chair of Advanced Ceramic Materials, Straße des 17. Juni 135, 10623 Berlin, Germany
Copyright Elsevier

Mars regolith simulant (MGS-1) was densified for the first time via a cold sintering process (CSP) as a novel in-situ resource utilization (ISRU) concept. The technique comprises the utilization of NaOH solution as a liquid media during the densification of simulant powder with <100 μm particle size. In as short as 30 min, with the increase in the NaOH concentration (from 3 M to 10 M) and processing temperature (from 150 °C to 250 °C), the relative densities of the regolith compacts and the mechanical properties were enhanced. The artifacts produced with Mars regolith simulant powder at 250 °C using 10 M NaOH solution yielded a relative density of around 88% and compressive strength reaching ~45 MPa.

^1,2Brandon G. Radoman-Shaw,³Ralph P. Harvey,⁴Gustavo Costa,⁴Nathan S. Jacobson,⁵Amir Avishai,⁴Leah M. Nakley,⁴Daniel Vento
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.13902]
¹Department of Mathematical, Physical, and Engineering Sciences, Texas A&M University – San Antonio, San Antonio, Texas, 78224 USA
²Department of Geography and Environmental Studies, Texas State University, San Marcos, Texas, 78666 USA
³Department of Earth, Environmental, and Planetary Science, Case Western Reserve University, Cleveland, Ohio, 44106 USA
⁴NASA Glenn Research Center, Cleveland, Ohio, 44135 USA
⁵Carl Zeiss SMT-PCS, Pleasanton, California, 94588 USA
Published by arrangement with John Wiley & Sons

Climate models for Venus rely heavily on theoretical modeling and laboratory experimentation due to the extreme surface conditions of the planet and limited in situ surface data. To better explore the relative importance of reactions between the surface and the atmosphere on Venus, we exposed representative volcanic glasses and basaltic minerals to a large-scale simulation of Venus surface conditions with a realistic atmospheric composition. This study consistend of two experiments of 42 and 80 days that replicated both physical conditions and atmosphere composition derived from available in situ near-surface data using the Glenn Extreme Environment Rig (GEER) at the NASA Glenn Research Center. These experiments revealed significant reactivity of common Ca-bearing pyroxenes (diopside and augite) to form anhydrite. Olivine and labradorite showed minimal reactivity. Volcanic glasses, including both natural and synthetic samples, were exceptionally reactive, rapidly forming both anhydrite and thénardite (Na2SO4), as well as transition metal sulfates (i.e., Cu, Cr), halite (NaCl), and sylvite (KCl). Our results document chemical and textural alteration of sample surfaces and provide sufficient evidence for an active sulfur sink on multiple samples, with sulfates as the dominant secondary mineralogy. These experiments suggest likely surface mineralogies and solid phases present on Venus’ surface with significant implications for upcoming missions and provide new data for comparison to high-temperature mineral–gas reactions prevalent on Venus, Earth, and Io.

¹Daiki Yamamoto,²Noriyuki Kawasaki,^3,4Shogo Tachibana,³Michiru Kamibayashi,²Hisayoshi Yurimoto
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2022.09.006]
¹Department of Earth and Planetary Science, Tokyo Institute of Technology, Ookayama, Tokyo 152-8550, Japan
²Department of Natural History Sciences, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
³Department of Earth and Planetary Science, The University of Tokyo, Hongo, Tokyo 113-0033, Japan
⁴Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa
Copyright: Elsevier

Coarse-grained igneous calcium-aluminum-rich inclusions (CAIs) are suggested to have experienced gas-melt isotope exchange of oxygen during the melting events of their precursors. Therefore, their oxygen isotope variation would preserve information about the high-temperature processes in the earliest Solar System. We experimentally determined oxygen isotope exchange kinetics between CAI analog melt and carbon monoxide (CO) gas at 1420°C and 1460°C under CO gas partial pressures of 0.1, 0.5, and 1 Pa to understand the role of CO gas on the oxygen isotope exchange. We observed oxygen isotope zoning profiles inside the reacted samples that formed through the oxygen isotope exchange reaction at the melt surface and oxygen diffusion in the melt. The zoning profiles were fitted using a three-dimensional spherical diffusion model with time-dependent surface concentration. The oxygen isotope exchange efficiency for colliding CO molecules is estimated to be ∼3.3 × 10–4, which is much smaller than that for H2O (0.28). The oxygen diffusion coefficient obtained in this study is similar to that obtained in the oxygen isotope exchange experiments between the CAI melt and H2O, suggesting that the diffusion species in the melt is O2–, despite the surrounding atmospheres.

A comparison of the isotope exchange reaction kinetics between (1) CAI melt and CO gas, (2) CAI melt and H2O gas, and (3) CO and H2O gases shows that the reaction rate decreases in the order of (3), (2), and (1). The rapid isotope exchange of the reaction (1) indicates that the oxygen isotopic compositions of H2O and CO should have been equilibrated during the melting and crystallization processes of igneous CAIs. Both H2O and CO change the oxygen isotope compositions of molten CAI in the same direction, although reaction (2) controls the isotope exchange timescale between the CAI melt and surrounding gas. Our dataset demonstrates that type B CAIs having melilite with homogeneous oxygen isotope composition should have been heated for 2–3 days at PH2 > 100 Pa above the melilite liquidus (∼1400°C) in the solar protoplanetary disk.

^1,2Lucas Demaret,³Ian B. Hutchinson,³Richard Ingley,³Howell G.M. Edwards,
⁴Nathalie Fagel,⁵Philippe Compere,²Emmanuelle J. Javaux,¹Gauthier Eppe,¹Cédric Malherbe
Astrobiology 22, 9 Link to Article [https://doi.org/10.1089/ast.2021.0128]
¹Mass Spectrometry Laboratory, MolSys Research Unit, University of Liege, Liege, Belgium.
²Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liege, Liege, Belgium.
³Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom.
⁴Laboratory Argiles, Géochimie et Environnements Sédimentaires, University of Liege, Liege, Belgium.
⁵Laboratory of Functional and Evolutionary Morphology, UR FOCUS, and Centre for Applied Research and
Education in Microscopy (CAREM), University of Liege, Liege, Belgium.

We currently do not have a copyright agreement with this publisher and cannot display the abstract here

^1,2Piotr Rzymski,³Piotr Klimaszyk,⁴Nadiia Kasianchuk,²Paulina Jakubiak,⁵Jędrzej Proch,⁵Przemysław Niedzielski
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2022.115263]
¹Department of Environmental Medicine, Poznan University of Medical Sciences, Poznan, Poland
²Integrated Science Association (ISA), Universal Scientific Education and Research Network (USERN), Poznań, Poland
³Department of Water Protection, Adam Mickiewicz University, 61-642 Poznań, Poland
⁴Faculty of Biology, Adam Mickiewicz University, 61-642 Poznań, Poland
⁵Department of Analytical Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Poznan, Poland
Copyright Elsevier

There is evidence of large subglacial reservoirs of liquid water on Mars, while the debate continues on whether any surface water intermittently flows following the subsurface ice melting in selected locations. The chemical conditions of waters that could be present on Mars were previously subject to modeling studies or experimental research that did not involve perchlorates which are known to be present in Martian regolith. Therefore, the present experimental research aimed to understand the chemistry of water incubated for 21 days with the Martian regolith simulant MGS-1 mixed with different levels of perchlorate (0.25–1.0% corresponding to 1.5–6.0 mM ClO4− ions). The dissolution of chemical compounds from MGS-1 was rapid with electric conductivity (EC) in the 1.8–2.3 mS/cm range after 1 h incubation. Throughout the experiment, fluctuations of pH, EC and oxidation-reduction potential were observed, although generally, the water was rich in ions, highly oxidized and had a circumneutral pH. Dominant elements included S, Mg, Ca, Na, K and Fe. Two patterns of element concentrations were observed: (1) a rapid increase with a peak 3 h after flooding the regolith and then a gradual decrease indicating adsorption and immobilization (Al, Cr, Fe, Si and Ti), and (2) a gradual increase in concentration throughout the experiment (Ca, K, Mg, Na and S). The presence of perchlorate in the simulant did not affect the general patterns of water chemistry parameters, although it appeared to enhance the leaching out of Mg, Na, S (with max concentrations noted in the presence of 1.0% perchlorate), Al, Ca (0.5%) and Cr, Fe, Si and Ti (0.25%). No detectable concentrations of Mn and P were leached from the regolith simulant throughout the experiment. This study provides a pilot experimental overview of the combined physicochemical conditions that modern liquid water on Mars could present with the potential implications for the survival of biological life and use as an in situ resource.

^{1,2 3}M.Millan et al. (>10)
Joournal of Geophysical Research (Planets) (in Press) Open Access Link to Article [https://doi.org/10.1029/2021JE007107]
¹Department of Biology, Georgetown University, Washington, DC, USA
²NASA Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, MD, USA
³Laboratoire Atmosphère, Observations Spatiales (LATMOS), LATMOS/IPSL, UVSQ Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt, France
Published by arrangement with John Wiley & Sons

The Sample Analysis at Mars (SAM) suite instrument on board NASA’s Curiosity rover has characterized the inorganic and organic chemical composition of seven samples from the Glen Torridon clay-bearing unit. A variety of organic molecules were detected with SAM using pyrolysis (up to ∼850°C) and wet chemistry experiments coupled with evolved gas analysis (EGA) and gas chromatography-mass spectrometry (GCMS). SAM EGA and GCMS analyses revealed a greater diversity and abundance of sulfur-bearing aliphatic and aromatic organic compounds in the sediments of this Gale crater unit than earlier in the mission. We also report the detection of nitrogen-containing, oxygen-containing, and chlorine-containing molecules, as well as polycyclic aromatic hydrocarbons found in Glen Torridon (GT), although the sources of some of these organics may be related to the presence of chemical reagents in the SAM instrument background. However, sulfur-bearing organics released at high temperature (>600°C) are likely derived from martian sources (e.g., igneous, hydrothermal, atmospheric, or biological) or exogenous sources and consistent with the presence of recalcitrant organic materials in the sample. The SAM measurements of the GT clay-bearing unit expand the inventory of organic matter present in Gale crater and is also consistent with the hypothesis that clay minerals played an important role in the preservation of ancient refractory organic matter on Mars. These findings deepen our understanding of the past habitability and biological potential of Gale crater.

¹G. Schmidt,²E. Luzzi,²A.P. Rossi,³M. Pondrelli,¹A. Apuzzo,¹F. Salvini
Journal of Geophysical Research (Planets) (in Press) Link to Article [https://doi.org/10.1029/2022JE007320]
¹Department of Science, Università degli studi Roma Tre, Rome, Italy
²Department of Physics and Earth Sciences, Jacobs University Bremen, Bremen, Germany
³International Research School of Planetary Sciences, Università d’Annunzio, Pescara, Italy
Published by arrangement with John Wiley & Sons

The formation of layered mounds on Mars remains a major topic of debate, with the relationship between their deposition and chemical alteration a major aspect still to be constrained. The association these deposits have with hydrated minerals indicates aqueous processes were active in their past, however the extent and duration of this aqueous period has yet to be fully realized. We studied compositional, stratigraphical, and structural characteristics of two separate layered deposits within Becquerel crater, Arabia Terra, to constrain their origins and the intensity of past aqueous activity. We find that due to key differences in composition, layering, and deformation between the two deposits, the timing of important depositional changes within Becquerel can be identified. We propose a scenario involving differences in fluid expulsion intensity and water level between the two layered deposits, in which diverse depositional and post-depositional environments were able to form. Furthermore, internal collapsing and deformation of the main mound might reflect that fluid upwelling persisted below the mound after formation. Determining the relationship between these two deposits is an important step in unraveling the past climate of Arabia Terra, and more broadly Mars. The evidence of protracted fluid expulsion represents a unique opportunity for future missions searching for signs of past life.

¹Yazhou Yang,²Te Jiang,¹Yang Liu,¹Yuchen Xu,^2,3Hao Zhang,⁴Heng-Ci Tian,⁴Wei Yang,¹Yongliao Zou
Journal of Geophysical Research (Planets)(In Press) Link to Article [https://doi.org/10.1029/2022JE007453]
¹State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, China
²Planetary Science Institute, School of Earth Sciences, China University of Geosciences, Wuhan, China
³CAS Center for Excellence in Comparative Planetology, Hefei, China
⁴Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
Published by arrangement with John Wiley & Sons

The Chang’e-5 (CE-5) mission has successfully returned samples from a site that is much younger than the sites of all previous lunar sampling missions. Sample analysis results reported so far have revealed a more complex sampling area than previously thought, casting uncertainties over the interpretation of remote sensing spectral data and the U and Th abundance derived from the orbital data. Laboratory spectral measurement of the returned samples can serve as validation of remote sensing observations and thus help refine our understanding of the geological evolution of the landing region. In this study we report detailed micro mid-infrared (MIR) spectral characteristics of individual soil grains of CE-5 samples. The spectral analysis results show that the CE-5 olivine grains have low Fo (molar Mg/[Mg + Fe] × 100) consistent with previous studies, indicating a Fe-rich source region of the mantle or a highly evolved magma. These olivine grains show high level of crystallinity, implying low degree of space weathering. Most of the CE-5 glasses analyzed are spectrally consistent with mare impact glasses, despite that a few of them may have a volcanic origin. These laboratory spectral analysis of CE-5 samples in the MIR wavelengths at a micro scale, together with the derived MIR optical constants of the olivine, pyroxene, plagioclase, and glass grains, provide important input for the modeling and interpretation of thermal remote sensing data of the Moon.

¹A.Rudolph et al. (>10)
Journal of Geophysical Research (Planets) (in Press) Link to Article [https://doi.org/10.1029/2021JE007098]
¹Purdue University, West Lafayette, United States
Published by arrangement with John Wiley & Sons

Glen Torridon (GT) is a recessive-trough feature on the northwestern slope of “Mt. Sharp” in Gale crater, Mars with the highest Fe-/Mg-phyllosilicates abundances detected by the Curiosity rover to date. Understanding the origin of these clay minerals and their relationship with diagenetic processes is critical for reconstructing the nature and habitability of past surface and subsurface environments in Gale crater. We aim to constrain the distribution and extent of diagenesis using compositional and morphological trends observed by visible-to-near infrared reflectance spectra in GT from Mastcam and ChemCam, supported by high-resolution images from the Mars Hand Lens Imager. Spectral features consistent with nontronite and fine-grained red hematite are ubiquitous throughout lower GT, and are strongest where diagenetic features are limited, suggesting that both were formed early, before burial. Diagenetic features increase in both abundance and diversity farther up-section, and we observe morphologic evidence for multiple episodes of diagenesis, with the edge of a diagenetic front partially preserved in the middle stratigraphic member, Knockfarril Hill. Near the contact between GT and the overlying Greenheugh pediment capping unit, we observe a lack of clay minerals with signatures consistent instead with coarse-grained gray hematite, likely formed through late-diagenetic alteration. We hypothesize that the sandstone-dominant Stimson formation acted as a conduit for diagenetic fluid flow into the area and that the clay-rich impermeable GT slowed the flow of those fluids, leading to enhanced alteration surrounding the clay-rich portions of GT, including within the nearby Vera Rubin ridge.