¹I. Weber, ¹M.P. Reitze, ¹T. Heyer, ¹A. Morlok, ¹T. Grund, ¹H. Hiesinger
Advances in Space Sciences (in Press) Open Access Link to Article [https://doi.org/10.1016/j.asr.2025.12.048]
¹Universität Münster, Institut für Planetologie, Wilhelm-Klemm-Str. 10, 48149 Münster

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¹Roberto Conconi,¹Hugues Leroux,²Maya Marinova,¹Sylvain Laforet,¹Damien Jacob,³Léna Jossé,³Alice Aléon-Toppani,³Zélia Dionnet,³Rosario Brunetto,¹Corentin Le Guillou
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.70083]
¹Universite de Lille, CNRS, INRAE, Centrale Lille, UMR 8207-UMET-Unit et Materiaux et Transformations, Villeneuve d’Ascq,France
²Universite de Lille, CNRS, INRAE, Centrale Lille, Universit´e Artois, FR 2638-IMEC-Institut Michel-Eugene Chevreul,Villeneuve d’Ascq, France
³Universite Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale, Orsay, France
Published by arrangement with John Wiley & Sons

Samples returned from asteroid Ryugu by the Hayabusa2 mission are dominated by fine-grained matrix material made of phyllosilicates and nanosulfides. Here, we report the mineralogical, textural, and chemical characteristics of nanosulfide-rich regions identified in Ryugu particles. High-resolution scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy reveal nanoscale heterogeneities in sulfide composition and morphology, indicating formation under variable conditions. Nanosulfide-rich regions are dominated by the presence of mackinawite (FeS) and pyrrhotite (Fe1-xS), in different proportions. Mackinawite, identified for the first time in Ryugu, occurs as well-crystallized lamellar crystals with some areas containing greigite (Fe3S4) and others showing signs of oxidation. In contrast, pyrrhotite appears either as euhedral nanocrystals or as structurally complex grains composed of stacked platy segments, which are characterized by numerous defects, including inclusions and planar defects. The distribution and associations of these phases are consistent with low-temperature aqueous alteration under alkaline and reducing conditions, likely occurring in Ryugu’s parent body. The presence of mackinawite implies complex thermodynamic and kinetic constraints and suggests the presence of localized fluids in which Fe concentrations exceeded those of S by an order of magnitude.

^1,2Walter Alvarez
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.70084]
¹Department of Earth and Planetary Science, University of California, Berkeley, California, USA
²Osservatorio Geologico di Coldigioco, Apiro, Italy
Published by arrangement with John Wiley & Sons

Astronomy and geology: the first deals with myriad, enormous, unreachable objects seen at great distances and at very low resolution; the other investigates one tiny (by comparison) object, Earth, at close range, from planetary scale down to almost atomic resolution in the laboratory. Planetary Science, studying solar system objects, to some extent bridges the gap between astronomy and geology. Astronomers mostly look up; geologists mostly look down. This paper lists cases where studies in one of those fields have contributed to understanding in the other. The central focus is on investigations of the Cretaceous and Paleogene pelagic Scaglia limestone in the Italian Apennine Mountains where geologic studies bear on five classes of solar system objects. The classes are separated by three orders of magnitude in size: the Moon-forming impactor, bolides that form craters on Earth, meteorites, meteor-forming grains, and extraterrestrial dust. The paper closes by calling attention to LIGO, the Laser Interferometer Gravitational-Wave Observatory, in which astronomical discoveries made by looking down have yielded a geological discovery done by looking up. LIGO has detected distant collisions involving black holes and neutron stars by measuring infinitesimal distortions of the Earth, which in turn have shown that at least some of Earth’s supply of heavy elements has been created by collisions of pairs of neutron stars—a major contribution to geochemistry and cosmochemistry.

¹N. Zimmermann,¹M. Safari,¹H. Nekvasil
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [ https://doi.org/10.1029/2024JE008906]
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2024JE008906]
¹Department of Geosciences, Stony Brook University, Stony Brook, NY, USA
Published by arrangement with John Wiley & Sons

Martian magmas compositionally resemble those from terrestrial continental hotspot magmatic suites, characterized by low OH and high Cl and S contents. The magmatic gases exsolved from such magmas transport a variety of metal complexes and, upon cooling, precipitate vapor-deposits into vugs and fractures within rocks and on the surfaces of pyroclastics, which are then added to surface fines. Experiments investigated trace element behavior during magmatic degassing as a potential signature of this magmatic process. Low-pressure experimental degassing of P-rich basaltic magma containing Cl, Br, S, minor OH, and trace elements (Sr, Ge, Ga, Zn, Pb, Rb, Cs, Se, Cu, La, and Lu) demonstrated that the gas-transported trace metals become incorporated into vapor-deposited Cs-Pb-Zn-Rb-bearing halides, Ge-Ga-bearing iron oxides, Zn-Se-Cu-bearing sulfides, alkali and iron sulfates, Ge-bearing silicates, rare earth phosphates, and elemental metals. Low-OH and high-Cl magmatic systems produce a variety of halides but inhibit Fe-oxide formation. S-rich systems produce vapor-deposited Na-, K-, and Fe-sulfates, Zn-Cu-Se bearing sulfides, and iron oxides. These results provide a signature for determining the possibility of a significant role for magmatic gas in producing secondary minerals and volatile trace element enrichment in the Gusev plains, Columbia Hills, Jezero crater, and Gale crater. A hallmark of vapor-deposited phases is the presence of local heterogeneities in “alteration” phases and in trace element signatures due to the superposition of high and low temperature phases.

¹E. Caminiti,²S. Besse,³A. Doressoundiram,^4,5J. Wright
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2025JE009359]
¹Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Japan
²European Space Agency (ESA), European Space Astronomy Center (ESAC), Madrid, Spain
³LIRA, Observatoire deParis, Université PSL, CNRS, Sorbone Université, Université de Paris, Meudon, France
⁴School of Physics and Astronomy, University of Leicester, Leicester, UK,
⁵School of Physical Sciences, The Open University, Milton Keynes, UK
Published by arrangement with John Wiley & Sons

NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging mission hasrevealed that about 27% of the surface of Mercury is covered by smooth plains, which are mostly volcanic inorigin. These plains are mainly located in the northern hemisphere, as well as within and around majorimpact basins. We used Mercury Atmospheric and Surface Composition Spectrometer data to perform anexhaustive spectral analysis of five major impact basins: Caloris, Rembrandt, Beethoven, Tolstoj, andRachmaninoff. We highlighted the existence of a new high‐reflectance spectral unit, that had previously onlybeen identified within the Rembrandt basin, as a major unit being more widespread. We named this new unitYoung High‐reflectance Red Plains. We found a common sequence of volcanic episodes that infilled thebasins and shaped their current surface spectral properties. We have shown that the size of the basin and theage of the volcanic infills are likely important parameters for the layering of different volcanic plains,defining the surface spectral units. Our study gives access to mantle properties, and we suggest thatheterogeneity in the mantle is certainly not necessary to explain the spectral properties of effusive volcanismassociated with impact basins. Future observations by the ESA‐JAXA‐BepiColombo mission are eagerlyawaited to better constrain the planet’s spectral, compositional, morphological, and geophysical surfaceproperties.

¹S.A.Connell et al. (>10)
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2025JE009243]
¹Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, USA
Published by arrangement with John Wiley & Sons

Investigating the stability of hydrated minerals is integral for examining the preservation ofrocks for potential Mars Sample Return and has major implications for models that use rover‐basedobservations to quantify Mars’ global water budget. The Mars 2020 Perseverance rover produces abrasionpatches to investigate fresh rock surfaces at Jezero crater, Mars. However, due to operational constraints, thefull analysis process typically takes several martian days (sols), and freshly exposed hydrated minerals maydehydrate upon atmospheric exposure between abrasion patch creation and their analyses. To assess thepotential for short‐term dehydration, the SuperCam instrument conducted the first in situ rover‐based dehydration experiment on rock exposures of the “Bright Angel formation.” The SuperCam andSHERLOC rover instruments indicated that the primary mineral hydration phases were Fe‐hydroxides, Ca‐sulfates such as bassanite (mixed with anhydrite), with possible minor contributions from non‐interlayer‐waterphyllosilicates (e.g., hydroxyl‐bearing only). The experiment involved a four‐sol sequence of observations onthe Steamboat Mountain abrasion patch, beginning just 22 min after abrasion. Dehydration was assessed bytracking changes in the 1.93 μm H2O absorption feature, which is sensitive to structural, absorbed, andadsorbed water. No significant changes in hydration were observed over the 93 hr, suggesting that the exposedminerals were already in a low hydration state and/or exhibit high stability under current martian surfaceconditions. These findings imply bulk rocks with low hydration and high stability minerals may not dehydrateupon exposure to the modern martian atmosphere on short time scales, consistent with predictions fromlaboratory simulations of Mars‐like environments.

^1,2Angel Mojarro,²José C. Aponte,²Jason P. Dworkin,²Jamie E. Elsila,²Daniel P. Glavin^3,4,5, Harold C. Connolly Jr.,³Dante S. Lauretta
Proceedings of the Nstional Academy of Sciences of the USA (in Press) Open Access Link to Article [https://doi.org/10.1073/pnas.25124611]
¹National Aeronautics and Space Administration Postdoctoral Program, Oak Ridge Associated Universities, Oak Ridge, TN 37830
²Solar System Exploration Division, National Aeronautics and Space Administration, Goddard Space Flight Center, Greenbelt, MD 20771
³Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721
⁴Department of Geology, School of Earth and Environment, Rowan University, Glassboro, NJ 08028
⁵Department of Earth and Planetary Sciences, American Museum of Natural History, New York, NY 10024

NASA’s OSIRIS-REx mission characterized the asteroid Bennu and delivered pristine samples of its regolith to Earth. Coordinated analyses of this primitive, carbonaceous material are elucidating the abiotic formation and inventory of prebiotic organic compounds in the early Solar System. Using pyrolysis and wet-chemistry techniques, we analyzed aggregate (unsorted particulate) material and three distinct stones that appear to correspond to different boulder types observed by the spacecraft. Results from the aggregate were consistent with previous work that detected the five canonical nucleobases and 14 of the 20 α-amino acids utilized by life to synthesize proteins. However, our analytical approach tentatively uncovered trace signals of a fifteenth α-amino acid, tryptophan, which has not been detected previously in extraterrestrial materials. Further, we found that the distributions of insoluble and soluble-derived organics differ between distinct stones, suggesting heterogeneous geologic processing within Bennu’s parent body. The distributions of alkylated polycyclic aromatic hydrocarbons resemble those in aqueously altered carbonaceous chondrites and are consistent with an abiotic origin through aqueous reactions. Our findings expand the evidence that prebiotic organic molecules can form within primitive accreting planetary bodies and could have been delivered via impacts to the early Earth and other Solar System bodies, potentially contributing to the origins of life.

¹S.A. Crowther et al. (>10)
Geochimica et Cosmochimica Acta (in Press) Open Access Link to Article [https://doi.org/10.1016/j.gca.2025.12.008]
Department of Earth and Environmental Sciences, The University of Manchester, UK
Copyright Elsevier

We report an I-Xe age of 7.94 ± 0.92 Myr after formation of calcium aluminium inclusions (CAI), and an iodine concentration of 67 ± 1 ppb for material returned from asteroid (162173) Ryugu by JAXA’s Hayabusa 2 mission. These were determined from multi-step laser heating xenon isotopic analysis of samples A0105-03 and A0105-12 (100 µg and 70 µg, respectively), the smaller of which had been neutron irradiated to convert 127I to 128Xe. The I-Xe age likely corresponds to the end of significant loss of volatiles from the parent body. A simple statistical model of all 24 xenon isotopic analyses of Hayabusa 2 material reported to date, including one sample that has an elevated concentration attributed to Xe-P7, suggests a bulk xenon content of 2.0–2.7 × 10−7 cm3 STP g−1 for such material. This is a factor of 12–60 times higher than suggested by analyses of CI chondrite meteorites that have been exposed to the terrestrial atmosphere.
The bulk xenon isotopic composition is enriched in the heavy isotopes (134, 136Xe) relative to Average Carbonaceous Chondrite (AVCC) xenon, consistent with loss of some planetary xenon (“Q-Xe”) during aqueous alteration allowing a greater relative contribution from presolar nanodiamonds than found in AVCC. The I-Xe age is within the range of I-Xe ages for aqueous alteration of CI material; it likely records either the closure of iodine-rich sites to xenon loss towards the end of a period of heating that was associated with aqueous alteration, or precipitation of iodine-bearing minerals driven by loss of water. We use a simple statistical model of xenon analyses of Ryugu material to investigate the concentration of xenon in CI material. The presence of the rare Xe-P7 component in one reported analysis increases the estimated gas concentration and so increases the discrepancy between xenon concentrations measured in Hayabusa2 samples and CI meteorites. This is consistent with a comparatively rare Xe-P7 carrier being susceptible to loss when exposed to the terrestrial atmosphere. We measured an iodine concentration of 67 ± 1 ppb, which is comparable to other analyses of CI chondrites by neutron-irradiation noble gas mass spectrometry (NI-NGMS). Our sample was sealed within a capillary tube during irradiation allowing us to monitor any gas lost from the sample; loss of iodine-derived 128Xe during the irradiation process cannot account for any discrepancy between our derived iodine concentration and those determined in carbonaceous chondrites by other methods.

¹Oliveira, B. H.,¹Snape, J. F.,¹Tartèse, R.,²Jeon, H.,²Whitehouse, M. J.,¹Joy, K. H.
Advances in Geochemistry and Cosmochemistry 1, 772 Open Access Link to Article [https://doi.org/10.33063/agc.v1i2.772]
¹Department of Earth and Environmental Sciences, The University of Manchester, Manchester, UK
²Department of Geosciences, The Swedish Museum of Natural History, Stockholm, Sweden

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¹Romain Tartèse et al. (>10)
Advances in Geochemistry and Cosmochemistry 1, 776 Open Access Link to Article [https://doi.org/10.33063/agc.v1i2.776]
¹Department of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom

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