The rock-forming minerals and macroscale mechanical properties of asteroid rocks

1,2Tang, Xuhai,1Xu, Jingjing,1Zhang, Yiheng,3Zhao, Haifeng,4Paluszny, Adriana,3Wan, Xue,1Wang, Zhengzhi
Engineering Geology 321, 107154 Link to Article [DOI 10.1016/j.enggeo.2023.107154]
1School of Civil Engineering, Wuhan University, Hubei, Wuhan, 430072, China
2Wuhan University Shenzhen Research Institute, Shenzhen, 518057, China
3Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences, Beijing, 100094, China
4Department of Earth Science and Engineering, Imperial College, London, United Kingdom#

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Synthesis of prebiotic organics from CO2 by catalysis with meteoritic and volcanic particles

1,2Peters, Sophia,1,2Semenov, Dmitry A.,3Hochleitner, Rupert,1,2Trapp, Oliver
Scientific Reports (in Press) Open Access Link to Article [DOI 10.1038/s41598-023-33741-8]
1Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, Munich, 81377, Germany
2Max Planck Institute for Astronomy, Königstuhl 17, Heidelberg, 69117, Germany
3Mineralogische Staatssammlung München, Theresienstr. 41, Munich, 80333, Germany

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In-situ measurement of hydrogen on airless planetary bodies using laser-induced breakdown spectroscopy

1Yumoto, Koki, 1Cho, Yuichiro, 2,3Kameda, Shingo, 1Kasahara, Satoshi, 1,4,5Sugita, Seiji
Spectrochimica Acta – Part B Atomic Spectroscopy 205, 106696 Link to Article [DOI
10.1016/j.sab.2023.106696]
1Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
2Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo, 171-8501, Japan
3Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Kanagawa, Sagamihara, 252-5210, Japan
4Research Center of Early Universe, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
5Planetary Exploration Research Center, Chiba Institute of Technology, Narashino, 275-0016, Japan

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A new shergottite martian meteorite analog system (SAS) for alteration experiments

1,2V. Fortier,2V. Debaille,1,3V. Dehant,4B. Bultel
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2023.105749]
1Earth and Life Institute, Université Catholique de Louvain-la-Neuve, Louvain-la-Neuve, Belgium
2Laboratoire G-Time, Université libre de Bruxelles, Bruxelles, Belgium
3Royal Observatory of Belgium, Bruxelles, Belgium
4Geosciences Paris Saclay, Université Paris-Saclay, Paris, France

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Bidirectional reflectance distribution function measurements of the Winchcombe meteorite using the Visible Oxford Space Environment Goniometer

1R. J. Curtis,1H. C. Bates,1T. J. Warren,1K. A. Shirley,1E. C. Brown,1A. J. King,1N. E. Bowles
Meteoritics & Planetary Scince (in Press) Link to Article [https://doi.org/10.1111/maps.14055]
1Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Oxford, UK
2Earth Sciences, Natural History Museum, London, UK
Published by arrangement with John Wiley & Sons

A laboratory study was performed using the Visible Oxford Space Environment Goniometer in which the broadband (350–1250 nm) bidirectional reflectance distribution function (BRDF) of the Winchcombe meteorite was measured, across a range of viewing angles—reflectance: 0°–70°, in steps of 5°; incidence: 15°, 30°, 45°, and 60°; and azimuthal: 0°, 90°, and 180°. The BRDF dataset was fitted using the Hapke BRDF model to (1) provide a method of comparison to other meteorites and asteroids, and (2) to produce Hapke parameter values that can be used to extrapolate the BRDF to all angles. The study deduced the following Hapke parameters for Winchcombe: w = 0.152 ± 0.030, b = 0.633 ± 0.064, and hS = 0.016 ± 0.008, demonstrating that it has a similar w value to Tagish Lake (0.157 ± 0.020) and a similar b value to Orgueil (0.671 ± 0.090). Importantly, the surface profile of the sample was characterized using an Alicona 3D® instrument, allowing two of the free parameters within the Hapke model φ and �¯, which represent porosity and surface roughness, respectively, to be constrained as φ = 0.649 ± 0.023 and �¯ = 16.113° (at 500 μm size scale). This work serves as part of the characterization process for Winchcombe and provides a reference photometry dataset for current and future asteroid missions.

V-type Asteroids as the Origin of Mesosiderites

1Guy Libourel,2Pierre Beck,3Akiko M. Nakamura,4Pierre Vernazza,5Clement Ganino,1Patrick Michel
The Planetary Science Journal 4, 123 Open Access Link to Article [DOI 10.3847/PSJ/ace114]
1Université Côte d’Azur, Lagrange, Observatoire de la Côte d’Azur, CNRS, Nice, France
2UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble, Grenoble, France
3Graduate School of Science, Kobe University, Japan
4Université Aix-Marseille, CNRS, Laboratoire d’Astrophysique de Marseille, Marseille, France
5Université Côte d’Azur, Géoazur, Observatoire de la Côte d’Azur, CNRS, Valbonne, France

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Petrographic constraints on the formation of silica-rich igneous rims around chondrules in CR chondrites

1Aimee Smith,1Rhian H. Jones
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14051]
1Department of Earth and Environmental Sciences, The University of Manchester, Manchester, UK
Published by arrangement with John Wiley & Sons

In the CR (Renazzo-like) chondrite group, many chondrules have successive igneous rim (IR) layers, with an outer layer that contains a silica mineral and/or silica-rich glass (silica-rich igneous rims, SIRs). Models for SIR formation include (1) accretion of Si-rich dust onto solid chondrule surfaces, followed by heating and cooling and (2) condensation of SiO(gas) onto the surface of partially molten chondrules. We evaluate these models, based on a petrographic study of five Antarctic CR chondrites that have undergone minimal secondary alteration. We obtained electron microprobe analyses of minerals and glass with quantitative wavelength-dispersive spectroscopy mapping, and identified silica polymorphs with Raman spectroscopy. Common SIRs contain silica, low-Ca pyroxene, Ca-rich pyroxene, Fe,Ni metal, ± glass ± plagioclase ± rare olivine. We also describe near-monomineralic SIRs where a narrow zone of cristobalite occurs at the outer edge of the chondrule. All crystalline silica is cristobalite, except for one SIR that consists of tridymite. Some rims contain silica-rich glass (>80 wt% SiO2) but no silica mineral. Features such as sharp interfaces and compositional boundaries between chondrules and SIRs indicate that SIRs were formed from solid precursors. Consideration of the stability fields of silica polymorphs and computed liquidus temperatures indicates that SIRs were heated to >1500°C for limited time periods, followed by rapid cooling, similar to conditions for chondrule formation. We infer that in the CR chondrule formation region, the same heating mechanism was repeated multiple times while the chemical composition of the nebular gas evolved to highly fractionated silica-rich compositions.

Silicon isotope constraints on terrestrial planet accretion

1Isaac J. Onyett,1Martin Schiller,1Georgy V. Makhatadze,1Zhengbin Deng,1,2Anders Johansen,1,3Martin Bizzarro
Nature 619, 539-544 Open Access Link to Article [DOI https://doi.org/10.1038/s41586-023-06135-z]
1Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Copenhagen, Denmark
2Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
3Institut de Physique du Globe de Paris, Université de Paris Cité, Paris, France

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Bounding the unknowns of Martian crustal heat flow from a synthesis of regional geochemistry and InSight mission data

1Katelyn R. Frizzell,1Lujendra Ojha,2Suniti Karunatillake
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115700]
1Department of Earth and Planetary Sciences, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
1Louisiana State University, Baton Rouge, LA, USA
Copyright Elsevier

The thermal evolution of terrestrial planets is primarily modulated by the distribution of heat-producing elements (HPE) within the crust and mantle. Chemical data from Martian meteorites suggest that Mars differentiated early, which led to an early partitioning of incompatible heat-producing elements in the crust. Previous estimates of Martian crustal heat flow that used the bulk regolith abundances of HPEs from the Gamma-Ray Spectrometer (GRS) suite on Mars Odyssey spacecraft have further corroborated this view of Mars, albeit with poorly known crustal column representativeness. Here we couple the GRS-derived chemical maps of Mars with estimates of crustal thickness and density from the InSight lander to revise the estimated Martian crustal heat flow. The mean crustal heat flow values range from 3.0 to 13.9 mW m−2 for the endmember gravity-derived crustal thickness models anchored by constraints from InSight. We also estimate the crustal heat flow from other factors such as the distribution of HPEs with depth and the Uranium content of the crust. Our results suggest that the mean crustal heat flow varies substantially across models, with the highest mean values being associated with higher densities and an increased enrichment of HPEs with depth. Further work is needed to constrain the crustal thickness of Mars, as the largest uncertainties in the estimate of crustal heat flow stem from uncertainty in the crustal thickness estimates, not geochemical variability. The results from this work corroborate previous estimates of a strong fractionation of heat-producing elements into the Martian crust.

In-situ phosphate U-Pb ages of the L chondrites

  • 1Craig Robert Walton et al. (>10)
    Geochmica et Cosmochimica Acta (in Press) Open Access Link to Article [https://doi.org/10.1016/j.gca.2023.07.012]
    1University of Cambridge, Institute of Astronomy, Madingley Road, Cambridge, CB3 0HA, United Kingdom
    Copyright Elsevier

The thermal history of asteroids is recorded by the radioisotopic ages of meteorites that derive from them. Radioisotopic ages may date a number of events, such as the cooling of a parent body during waning radiogenic metamorphism, rapid cooling experienced upon parent body break-up, and/or subsequent collision-induced reheating of material. However, sampling statistics for meteorite radioisotope ages are currently relatively low and most are derived from analyses of bulk material, therefore lacking the in-situ microtextural context that aids in distinguishing collisional events. Here, we present new in-situ apatite U-Pb ages for nine L chondrite meteorites using secondary ionisation mass spectrometry.

Our measurements greatly expand the L chondrite phosphate U-Pb age record and provide evidence for distinct stages in the thermal evolution of the L chondrite parent asteroid, including: early collisions driving parent body fragmentation- and/or exhumation-associated cooling at > 4530 Ma; onion-shell-style cooling with waning radiogenic metamorphism until 4500 Ma; late collisional reheating from 4480–4460 Ma; parent body break-up at 474± 22 Ma; and recent ejection events within several 10s of Myr of present day. We show that meteorite shock stage correlates with upper intercept age but is uncorrelated with lower intercept age. This outcome links the upper intercept ages alone to the preserved high-energy impact-related features in strongly shocked meteorites, which has important implications for our interpretation of the L chondrite U-Pb record.

We see no evidence in our record for collisional episodes between 3000–4400 Ma, i.e., the Late Heavy Bombardment. Our upper intercept age record hints that collision rates changed as a result of some dynamical instability at 4460–4480 Ma, which may have strongly depleted the main asteroid belt, and/or that L asteroid physical structure changed such that the shock metamorphic response to collisions was muted after this time, e.g., by the formation of weak rubble pile bodies. L chondrite phosphate U-Pb ages provide evidence for a heterogeneous early and shared late (less than 500 Ma) thermal history for the majority of L chondrite meteorites falling to Earth today. From this observation, we infer that most L chondrites derive from a single parent asteroid (in existence from around 4500–4440 Ma to 474± 22 Ma), which has since been disturbed to create an asteroid family. Our record of meteorite U-Pb ages traces out the thermal and dynamical evolution of the L chondrite asteroid. These observations can be used in future to benchmark dynamical models of Solar System evolution.