¹Iizuka, Tsuyoshi,^2,3Hibiya, Yuki,¹Yoshihara, Satoshi,⁴Hayakawa, Takehito
Astrophysical Journal Letters 979, L29 Open Access Link to Article [DOI 10.3847/2041-8213/ada554]
¹Department of Earth and Planetary Science, The University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo, 113-0033, Japan
²Research Center for Advanced Science and Technology, The University of Tokyo, Komaba 4-6-1, Meguro, Tokyo, 153-8904, Japan
³Submarine Resources Research Center, Japan Agency for Marine-Earth Science and Technology, Kanagawa, 237-0061, Japan
⁴Kansai Institute for Photon Science, National Institutes for Quantum Science and Technology, Umemidai 8-1-7, Kizugawa, Kyoto, 619-0215, Japan

The radioactive decay of short-lived 26Al-26Mg has been used to estimate the timescales over which 26Al was produced in a nearby star and the protosolar disk evolved. The chronology commonly assumes that 26Al was uniformly distributed in the protosolar disk; however, this assumption is challenged by the discordance between the timescales defined by the Al-Mg and assumption-free Pb-Pb chronometers. We find that the 26Al heterogeneity is correlated with the nucleosynthetic stable Ti isotope variation, which can be ascribed to the nonuniform distribution of ejecta from a core-collapse supernova in the disk. We use the Al-Ti isotope correlation to calibrate variable 26Al abundances in Al-Mg dating of early solar system processes. The calibrated Al-Mg chronometer indicates a ≥1 Myr gap between parent body accretion ages of carbonaceous and noncarbonaceous chondrites. We further use the Al-Ti isotope correlation to constrain the timing and location of the supernova explosion, indicating that the explosion occurred at 20-30 pc from the protosolar cloud, 0.94 +0.25/-0.21 Myr before the formation of the oldest solar system solids. Our results imply that the Sun was born in association with a ∼25 Mʘ star.

¹Takaaki Noguchi,^2,3Takahito Tominaga,^2,4Minako Takase,⁵Akira Yamaguchi,⁵Naoya Imae
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14324]
¹Division of Earth and Planetary Science, Kyoto University, Kyoto, Japan
²Department of Earth and Planetary Science, Kyushu University, Fukuoka, Japan
³Kai Industries Co. Ltd., Gifu, Japan
⁴Fukuoka City Science Museum, Fukuoka, Japan
⁵National Institute of Polar Research, Japan, Tokyo, Japan
Published by arrangement with John Wiley & Sons

Over a period of 16 years, we collected Antarctic micrometeorites (AMMs) preserved in 1-t snow samples from the surface to a depth of ~10–15 cm near Dome Fuji Station, Antarctica. A total of 1025 AMMs were identified: 843 unmelted AMMs, 51 scoriaceous ones, and 131 cosmic spherules. Their average sizes were 40, 64, and 40 μm, respectively. The accretion rate of AMMs was inferred to be (3.3 ± 1.8) × 103 t year−1, based on the snow accumulation rate near Dome Fuji Station. We compared the Dome Fuji collection (DFC) with our previous Tottuki #5 collection (T5C) recovered from blue ice in 2000. Regardless of the collection methods, the full range size distributions of AMMs were well fitted by lognormal functions. In 2019 and 2020, we applied a freeze-drying (FD) system to collect AMMs. We identified 21 AMMs from 17 kg of surface snow. Both GEMS (glass with embedded metal and sulfide)-rich chondritic porous (CP) AMMs and hydrated fine-grained (H f-g) AMMs were identified. No detectable mineralogical differences were observed between a CP AMM from the DFC-FD and one from the DFC, suggesting that ~6 h of exposure to cold water (<8.7°C) did not affect the mineralogy of CP AMMs.

^1,2N.G. Rudraswami, ^1,2V.P. Singh, ¹M. Pandey
Chemical Geology 677, 122628 Link to Article [https://doi.org/10.1016/j.chemgeo.2025.122628]
¹National Institute of Oceanography (Council of Scientific and Industrial Research), Dona Paula, Goa 403004, India
²Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India

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^1,3Hyung, Eugenia,^2,3Cherston, Juliana,^1,3Jacobsen, Stein B.,^2,3Loeb, Abraham Avi
Chemical Geology 677, 122627 Link to Article [DOI 10.1016/j.chemgeo.2025.122627]
¹Dept. of Earth and Planet. Sci., Harvard Univ., Cambridge, 02138, MA, United States
²Dept. of Astronomy, Harvard Univ., Cambridge, 02138, MA, United States
³Interstellar Expedition of the Galileo Project, Cambridge, 02138, MA, United States

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^1,2Dettori, Riccardo^1,2Goldman, Nir
Journal of Physical Chemistry A, 129 583-595 Link to Article [DOI 10.1021/acs.jpca.4c05881]
¹Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, 94550, CA, United States
²Department of Physics, University of Cagliari, CA, Monserrato, 09042, Italy
³Department of Chemical Engineering, University of California, Davis, 95616, CA, United States

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¹Elmer J.W.,¹Bellino J.S.
Acta Astronautica 229, 578-590 Link to Article [DOI 10.1016/j.actaastro.2025.01.018]
¹Materials Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA, United States

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^1,2Yanze Su,^1,2Luyuan Xu,^1,2Meng-Hua Zhu
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2024JE008501]
¹State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Macau, China
²CNSA Macau Center for Space Exploration and Science, Macau, China
Published by arrangement with John Wiley & Sons

The composition of lunar samples sheds light on the Moon’s evolutional history. Analyses of Chang’e-5 (CE-5) lunar soils showed <5% of foreign materials, significantly less than numerical predictions (∼10%). To address this inconsistency, we simulated the impact gardening process, accounting for distal ejecta, and tracked the compositional changes in the top 1 m layer at CE-5 landing area over time. Our results show that impact gardening brings deeper local materials to the surface, leading to a mixture that reduces the distal ejecta proportion within the top 1 m layer from which the soils were collected. After 2.0 Gyr of impact gardening, most materials of the top 1 m layer originate from the upper layer (depth <30 m) of local basalts, with distal ejecta as a minor component (∼2.7 vol.%), consistent with CE-5 soils analyses. Our results emphasize the profound influence of impact gardening on the composition of lunar soils.

¹Parsons Levben, ¹Black Benjamin, ²Karunatillake Suniti
Icarus (in Press) Open Access Link to Article [https://doi.org/10.1016/j.icarus.2025.116491]
¹Department of Earth and Planetary Sciences, Rutgers University, 610 Taylor Rd., Piscataway, NJ 08854, United States of America
²Department of Geology and Geophysics, Louisiana State University, E235 Howe Russell Kniffen, Baton Rouge, LA 70803, United States of America
Copyright Elsevier

The sulfur cycle on Mars plays a critical role in shaping its surface and atmospheric chemistry. Mars’ near-surface sulfur inventory largely originated from mantle-derived magmas that erupted during the Noachian, Hesperian, and Amazonian eons. Satellites permit measurements of bulk sulfur in Martian regolith, and rover and meteorite measurements capture snapshots of sulfur in specific samples. However, the concentration of sulfur in Martian magmas prior to degassing, which governs the transfer of interior sulfur to the near-surface, remains uncertain. Because Mars’ mantle may be sulfur-rich, most primary mantle melts are expected to be in equilibrium with residual mantle sulfide. In this work, we therefore use Gamma Ray Spectroscopy (GRS) regional maps of bulk surface chemistry to calculate the sulfur concentration at sulfide saturation (SCSS) for late Noachian through Amazonian Martian magmas. We further consider a range in mantle source sulfur and constraints on degree of melting to account for mantle sulfide exhaustion, in order to estimate sulfur concentrations in primitive melts. We find that the concentration of sulfur in Martian magmas ranged between ~1330 and 4550 ppm S. These results underscore that the GRS sulfur concentration data, from ~15,000 and 29,000 ppm globally, do not represent the sulfur content of primitive basalts, but rather reflect myriad processes that cycled sulfur within the critical zone of exchange between the atmosphere and crust. We define a new metric, the Sulfur Enrichment Index (SEI), that tracks the enrichment in present-day regolith sulfur relative to the original magmatic sulfur concentration in volcanic regions. We show that sulfur release is inefficient for magmas emplaced at >1–2 km depth. Accounting for the total extruded volume of magma from the late Noachian through the Amazonian, our estimates of primary magmatic sulfur concentrations lead to a cumulative yield of ~2–68 × 1019 g of sulfur to the Martian atmosphere from ~3.8 Ga to the present. For comparison, only ~1018–1019 g of sulfur is evident within the upper decimeters of the Martian crust at mid-latitudes. We therefore infer that volcanogenic sulfur, like water, has likely been sequestered within Mars’ crust.

^1,2Paulina Skirak,^2,3Gabriela Opiła,¹Adam Piestrzyński,¹Gabriela Kozub-Budzyń,³Czesław Kapusta
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14318]
¹Faculty of Geology Geophysics and Environmental Protection, AGH University of Kraków, Kraków, Poland
²Space Technology Centre, AGH University of Kraków, Kraków, Poland
³Faculty of Physics and Applied Computer Science, AGH University of Kraków, Kraków, Poland
Published by arrangement with John Wiley & Sons

Results of microanalysis study of NWA 869 meteorite, an ordinary chondrite, where silicates, Fe-Ni alloys, and troilite are major constituents, are reported. The presented study of microtextures in metallic and sulfide grains provides information on processes occurring from the asteroid’s accretion, through the impacts until cooling. The presence of metal–silicate emulsion, swiss-cheese texture, and polycrystalline kamacite–troilite aggregates observed indicates very rapid increase in temperature due to impact. Fizzed troilite, slightly homogenized taenite domains, and intergrowth of native copper in plessite imply rapid cooling in isolated regions in space. Agrell effect on the interface of kamacite–taenite grains and non-corroded tetrataenite rims indicates that the sample contains rock fragments from a region unaffected directly by the impact or rapid heating. Diversity of petrological types, lithic clasts with shock grade higher than S3, shock-darkened clasts or impact melting rocks, and variation of microtextures suggest that the parent body of L-type chondrites after accretion, radiogenic metamorphism, and consequent formation of the onion–shell model broke up into debris after the impact of eucrite body.

^1,2Jon M. Friedrich,¹Eva M. Riveros,³Robert J. Macke,^2,4,5Steven J. Jaret,⁶Mark L. Rivers,^2,5,7Denton S. Ebel
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14320]
¹Department of Chemistry and Biochemistry, Fordham University, Bronx, New York, USA
²Department of Earth and Planetary Sciences, American Museum of Natural History, New York, New York, USA
³Vatican Observatory, Vatican City State
⁴Department of Physical Science, Kingsborough Community College, City University of New York, Brooklyn, New York, USA
⁵Department Earth and Environmental Sciences, CUNY Graduate Center, New York City, New York, USA
⁶GeoSoilEnviroCARS, The University of Chicago, Argonne National Lab, Lemont, Illinois, USA
⁷Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA
Published by arrangement with John Wiley & Sons

CI chondrites are poorly lithified and highly friable regolith breccias. To examine their physical properties and the nature of their breccation, we investigated nine samples of the Ivuna and Orgueil CI chondrites ranging in size from 1 mm to 4 cm in approximate diameter. The combined mass of unique material investigated in this work is 113 g. For our investigations, we use ideal gas pycnometry, 3-D laser scanning, x-ray computed microtomography (μCT), and accompanying digital data extraction techniques. We found that the bulk density of the samples ranged from 1.61 to 2.10 g cm−3. Larger samples tend to have a lower bulk density. Grain density (ranging from 2.44 to 2.55 g cm−3) is significantly less variable than the bulk density in our samples and the quantity of porosity (ranging from 14.6% to 33.8%) is the dominant factor in determining the bulk density of CI chondrite material. Our μCT results show that the visible porosity across all sizes of our CI chondrite samples is in the form of cracks, but these cracks can account for less than two-thirds of the porosity in the CI chondrites. Other porosity is not visible, even at μCT resolutions of 2.7 μm voxel edge−1 and we conclude that it is sub-micron in nature. It is not clear if the cracks seen in our samples are indigenous to the chondrites or are a result of terrestrial processes. We also find that the CI chondrites are excellent examples of the fractal-like nature of brecciation, where clasts can be observed at all scales we imaged. The breccias are composed of sub-equant-shaped and sub-rounded-textured clasts like melt-free impact breccias on other solar system bodies. From our μCT volume and digital data extraction, we determine that the Ivuna CI chondrite breccia is organized: the mostly sub-equant clasts within our ~2 cm chunk of Ivuna have a mean diameter of 1.33 mm and their aligned longest axes define a lineation structure. We speculate that the lineation was imparted after fragmentation of the clasts by slight shear on the parent asteroid which could be the result of seismic-related granular flow or mild non-axial impact-related compaction. These data will help to place returned asteroidal material from asteroids 162173 Ryugu and 101955 Bennu and the CI chondrites into a mutual geological context.