¹Brent D. Turrin,²Fara Lindsay,¹Jeremy S. Delaney,^2,3,4Jisun Park,²Gregory F. Herzog,¹Carl Swisher Jr,⁵Cyrena A. Goodrich
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.13953]
¹Department of Earth and Planetary Sciences, Rutgers University, Piscataway, New Jersey, 08854 USA
²Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854 USA
³Physical Sciences, Kingsborough Community College of the City University of New York, Brooklyn, New York, 11235 USA
⁴Department of Earth and Planetary Sciences, American Museum of Natural History, New York, New York, 10024 USA
⁵Lunar and Planetary Institute, Universities Space Research Association, Houston, Texas, 77058 USA
Published by arrangement with John Wiley & Sons

The Almahata Sitta (AhS) meteorite consists of disaggregated clasts from the impact of the polymict asteroid 2008 TC3, including ureilitic (70%–80%) and diverse non-ureilitic materials. We determined the 40Ar/39Ar release patterns for 16 AhS samples (3–1500 μg) taken from three chondritic clasts, AhS 100 (L4), AhS 25 (H5), and MS-D (EL6), as well as a clast of ureilitic trachyandesite MS-MU-011, also known as ALM-A, which is probably a sample of the crust of the ureilite parent body (UPB). Based on our analyses, best estimates of the 40Ar/39Ar ages (Ma) of the chondritic clasts are 4535 ± 10 (L4), 4537–4555 with a younger age preferred (H5), and 4513 ± 17 (EL6). The ages for the L4 and the H5 clasts are older than the most published 40Ar/39Ar ages for L4 and H5 meteorites, respectively. The age for the EL6 clast is typical of older EL6 chondrites. These ages indicate times of argon closure ranging up to 50 Ma after the main constituents of the host breccia, that is, the ureilitic components of AhS, reached the >800°C blocking temperatures of pyroxene and olivine thermometers. We suggest that these ages record the times at which the clasts cooled to the Ar closure temperatures on their respective parent bodies. This interpretation is consistent with the recent proposal that the majority of xenolithic materials in polymict ureilites were implanted into regolith 40–60 Ma after calcium–aluminum-rich inclusion and is consistent with the interpretation that 2008 TC3 was a polymict ureilite. With allowance for its 10-Ma uncertainty, the 4549-Ma 40Ar/39Ar age of ALM-A is consistent with closure within a few Ma of the time recorded by its Pb/Pb age either on the UPB or as part of a rapidly cooling fragment. Plots of age versus cumulative 39Ar release for 10 of 15 samples with ≥5 heating steps indicate minor losses of 40Ar over the last 4.5 Ga. The other five such samples lost some 40Ar at estimated times no earlier than 3800–4500 Ma bp. Clustering of ages in the low-temperature data for these five samples suggests that an impact caused localized heating of the AhS progenitor ~2.7 Ga ago. In agreement with the published work, 10 estimates of cosmic-ray exposure ages based on 38Ar concentrations average 17 ± 5 Ma but may include some early irradiation.

¹Moromoto, Narumi,^1,2Kawai, Yosuke,^1,2Terada, Kentaro,³Miyahara, Masaaki, ⁴Takahata, Naoto,^4,5Sano, Yuji,³Fujikawa, Naoko,^6,7Anand, Mahesh
Mass Spectrometry 12, A0115 Open Access Link to Article [DOI 10.5702/massspectrometry.A0115]
¹Department of Earth and Space Science, Graduate School of Science, Osaka University, 1–1 Machikaneyama, Osaka, Toyonaka, 560–0043, Japan
²Forefront Research Center, Graduate School of Science, Osaka University, 1–1 Machikaneyama, Osaka, Toyonaka, 560–0043, Japan
³Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima, Higashi-Hiroshima, 739–8526, Japan
⁴Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Kashiwa, 277–8564, Japan
⁵Center for Advanced Marine Core Research, Kochi University, Kochi, Nankoku, 783–8502, Japan
⁶School of Physical Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom
⁷Department of Earth Sciences, The Natural History Museum, London, SW7 5BD, United Kingdom

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^1,2J.N. Rasera,¹J.J. Cilliers,²J.-A. Lamamy,^1,3K. Hadler
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2023.105651]
¹Department of Earth Sciences and Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, United Kingdom
²ispace Europe S.A, 5, rue de l’Industrie, L-1811, Luxembourg City, Luxembourg
³European Space Resources Innovation Centre (ESRIC), Luxembourg Institute of Science and Technology (LIST), Maison de l’Innovation, 5, avenue des Hauts-Fourneuax, L-4362, Esch-sur-Alzette, Luxembourg

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¹Bittaru, Ilaria et al. (>10)
Applied Radiation and Isotopes 194, 110651 Link to Article [DOI 10.1016/j.apradiso.2023.110651]
¹Universitá degli Studi di Torino, Via Pietro Giuria 1, Torino, 10125, Italy

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¹Tahir, Naeem Ahmad,¹Bagnoud, Vincent,¹Neumayer, Paul,²Piriz, Antonio Roberto,²Piriz, Sofia Ayelen
Scientific Reports 13, 1459 Open Access Link to Article [DOI 10.1038/s41598-023-28709-7]
¹GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, Darmstadt, 64291, Germany
²E.T.S.I. Industriales, Universidad de Castilla-La Mancha, Ciudad Real, 13071, Spain

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¹Mark A. Sephton,^2,3,4Queenie H. S. Chan,¹Jonathan S. Watson,⁵Mark J. Burchell,⁵Vassilia Spathis,⁴Monica M. Grady,⁴Alexander B. Verchovsky,⁴Feargus A. J. Abernethy,⁴Ian A. Franchi
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13952]
¹Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ UK
²Royal Holloway University of London, Egham Hill, TW20 0EX UK
³UK Fireball Network (UKFN), UK
⁴The Open University, Milton Keynes, MK7 6AA UK
⁵Department of Physics and Astronomy, University of Kent, Canterbury, CT2 7NH UK
Published by arrangement with John Wiley & Sons

The Winchcombe meteorite fell on February 28, 2021 in Gloucestershire, United Kingdom. As the most accurately recorded carbonaceous chondrite fall, the Winchcombe meteorite represents an opportunity to link a tangible sample of known chemical constitution to a specific region of the solar system whose chemistry can only be otherwise predicted or observed remotely. Winchcombe is a CM carbonaceous chondrite, a group known for their rich and varied abiotic organic chemistry. The rapid collection of Winchcombe provides an opportunity to study a relatively terrestrial contaminant-limited meteoritic organic assemblage. The majority of the organic matter in CM chondrites is macromolecular in nature and we have performed nondestructive and destructive analyses of Winchcombe by Raman spectroscopy, online pyrolysis–gas chromatography–mass spectrometry (pyrolysis–GC–MS), and stepped combustion. The Winchcombe pyrolysis products were consistent with a CM chondrite, namely aromatic and polycyclic aromatic hydrocarbons, sulfur-containing units including thiophenes, oxygen-containing units such as phenols and furans, and nitrogen-containing units such as pyridine; many substituted/alkylated forms of these units were also present. The presence of phenols in the online pyrolysis products indicated only limited influence from aqueous alteration, which can deplete the phenol precursors in the macromolecule when aqueous alteration is extensive. Raman spectroscopy and stepped combustion also generated responses consistent with a CM chondrite. The pyrolysis–GC–MS data are likely to reflect the more labile and thermally sensitive portions of the macromolecular materials while the Raman and stepped combustion data will also reflect the more refractory and nonpyrolyzable component; hence, we accessed the complete macromolecular fraction of the recently fallen Winchcombe meteorite and revealed a chemical constitution that is similar to other meteorites of the CM group.

^1,2,3Yanhua Peng et al. (>10)
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115493]
¹Institution of Meteorites and Planetary Materials Research, Key Laboratory of Planetary Geological Evolution at Universities of Guangxi Province, Guilin University of Technology, Guilin 541004, China
²Center for Lunar and Planetary Sciences, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
³Nanning College of Technology, Guilin 541006, China
Copyright Elsevier

Metallic iron (Fe0) particles with sizes ranging from a few nanometers to the submicroscopic scale and formed by space weathering are specific components of lunar soil. Previous studies have suggested that the iron significantly alters the optical properties of lunar soil. For example, nanophase metallic iron (npFe0) causes both reddening and darkening of the lunar soil spectrum, and submicroscopic metallic iron (SMFe) only causes darkening. Here, we prepared SMFe particles with an average size of ~180 nm embedded within melt glasses through carbothermal reduction experiments to analogize agglutinated glasses in the lunar soil. We evaluated the effect of SMFe content on visible and near-infrared (VIS–NIR) reflectance spectra of these lunar soil samples simulants. The spectral data show that SMFe content plays a key role in the optical properties of samples, including the average reflectance in the VIS-NIR range (400–2150 nm), and the absorption depth at ~2 μm. A small amount (0.05 wt%) of SMFe mainly causes significant spectral darkening, and the average reflectance is reduced by 50% when the SMFe content rises to 0.36 wt%. Both the average reflectance and the absorption depth at ~2 μm show a negative correlation with the SMFe content. We developed a quantitative model relating the spectral characteristics and the SMFe abundance based on experimental results. Thus, the SMFe contents play a key role in altering spectral characteristics of airless bodies during remote sensing spectroscopic detection.

^1,2Manuel Andrade et al. (>10)
Monthly Notices of the Royal Astronomical Society 518, 3850-3876 Open Access Link to Article [https://doi.org/10.1093/mnras/stac2911]
¹CITMAga, E-15782 Santiago de Compostela, Galiza, Spain
¹Observatorio Astronómico R. M. Aller (OARMA), Departamento de Matemática Aplicada, Escola Politécnica Superior de Enxeñaría (EPSE), Universidade de Santiago de Compostela (USC), Campus Terra, E-27002 Lugo, Galiza, Spain

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^1,2Zilong Wang,¹Wei Tian
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13957]
¹The Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, School of Earth and Space Sciences, Peking University, Beijing, China
²The Key Laboratory of Paleomagnetism and Tectonic Reconstruction of MNR, Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China
Published by arrangement with John Wiley & Sons

Mesosiderites are breccias composed of roughly equal parts of metal phases and silicate clasts. However, the parent body and formation process of mesosiderites remain enigmatic. Northwest Africa (NWA) 12949 is a newly found mesosiderite belonging to type 2A. One type of ultramafic clasts and four types of mafic clasts (gabbroic, poikilitic, subophitic, and cataclastic), compositionally consistent with diogenites and eucrites, have been identified in NWA 12949. However, these clasts have undergone different thermal histories, with cooling rates varying from ~0.0044 °C year−1 to a few °C h−1, and equilibrium temperatures varying from ~880 to 910 °C to ~1000 to 1100 °C. All the lithic clasts have undergone redox reactions during extensive metamorphism, forming excess troilite, chromite, merrillite, tridymite, and pyroxene with lower Fe/Mg and Fe/Mn. The petrology and mineralogy of NWA 12949 support a formation scenario involving two major impact events, and a candidate parent body of 4 Vesta.

¹Dagmara Oszkiewicz,¹Hanna Klimczak,²Benoit Carry,³Antti Penttilä,⁴Marcel Popescu,¹Joachim Krüger,^5,6Marcelo Aron Keniger
Monthly Notices of the Royal Astronomical Society 519, 2917–2928 Link to Article[https://doi.org/10.1093/mnras/stac3442]
¹Astronomical Observatory Institute, Faculty of Physics, Adam Mickiewicz University, Słoneczna 36, P-60-286 Poznań, Poland
²Observatoire de la Côte d’Azur, CNRS, Université Côte d’Azur, Laboratoire Lagrange, 06304 Nice, France
³Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
⁴Astronomical Institute of the Romanian Academy, 5 Cutitul de Argint, 040557 Bucharest, Romania
⁵Nordic Optical Telescope, Rambla José Ana Fernández Pérez 7, E-38711 Breña Baja, Spain
⁶Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark

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