Luca BINDI¹ et al. (>10)
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14377]
¹Dipartimento di Scienze della Terra, Universita di Firenze, Florence, Italy
Published by arrangement with John Wiley & Sons

We report the discovery of (Al,Cu)-bearing metallic alloys in two micrometeorites found in the Project Stardust collection gathered from urban rooftop environments in Norway. Most of the alloys are the same as those found in the Khatyrka meteorite and other micrometeorites, though one has a composition that has not been reported previously. Oxygen isotope ratio measurements using secondary ion mass spectrometry show that the Project Stardust samples reported here, like all earlier examples of natural (Al,Cu)-bearing alloys, contain material of chondritic affinity.

Tatsuhiro Michikami^a, Axel Hagermann^b
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2025.116693]
^aFaculty of Engineering, Kindai University, Hiroshima Campus, 1 Takaya Umenobe, Higashi-Hiroshima, Hiroshima 739-2116, Japan
^bLuleå University of Technology, Space Campus, 981 28 Kiruna, Sweden
Copyright Elsevier

In planetary science, the statistical properties of spatial distributions are frequently examined to understand the formation and evolution of a body’s surface. The surfaces of the asteroids directly explored by spacecraft are covered with numerous boulders and/or regolith particles. However, the spatial distribution of these boulders has not been statistically studied, although much statistical research has been done on the spatial distributions of craters. Thus, it is not known whether the spatial distribution of boulders on asteroids explored by spacecraft is random or not. Squyres et al. (1997) developed a simple model of crater formation and obliteration based on several assumptions, but some of their assumptions do not hold for boulders. In this study, we construct a simple model of the spatial distribution of boulders by verifying some assumptions, and investigate the effect of various assumptions and parameter variations on the model results. From these quantitative calculations, we investigate the spatial distribution of boulders on the asteroids Eros, Ryugu, and Itokawa. Our quantitative results show that boulders on Eros are spatially clustered at the 95 % confidence level. On the other hand, on Ryugu and Itokawa, decameter-sized boulders are spatially less clustered, while meter-sized small boulders are spatially clustered, all at the 95 % confidence level. This suggests that the clustered spatial distribution of small boulders on Ryugu and Itokawa can be explained by their migration.

James M. D. DAY¹, Hunter R. EDWARDS¹, Kim TAIT² , and Carl B. AGEE³
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14378]
¹Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
²Royal Ontario Museum, Toronto, Ontario, Canada
³University of New Mexico, Albuquerque, New Mexico, USA
Published by arrangement with John Wiley & Sons

To understand chemical variability within individual martian meteorites, we report major, minor, trace, and highly siderophile element abundances, as well as ¹⁸⁷Re-¹⁸⁷Os, for four separate rock fragments of gabbroic shergottite Northwest Africa (NWA) 6963. The compositions of these aliquots are consistent with data for NWA 6963 from Filiberto et al. (2018). Data reported for NWA 6963 in Day et al. (2018) and Tait and Day (2018) should no longer be used due to doubt in provenance of the sample fragment used in those studies. Genuine fragments of NWA 6963 show significant variability in elements due to different modal proportions of minerals. Terrestrial weathering effects appear to be most pronounced for Ba and Pb. The age and composition of NWA 6963 indicate that it may be related to enriched basaltic shergottites and some olivine–phyric and poikilitic shergottites that are referred to here as the “enriched shergottite group.” The ¹⁸⁷Re-¹⁸⁷Os systematics of the enriched shergottite group all conform to generation at ~180 million years from the same or similar mantle sources with long-term Re/Os enrichment on Mars. They show coherent fractional crystallization trends in plots of compatible elements with the possibility for impact-contaminated regolith assimilation in NWA 6963. The enriched shergottite group may represent magmatism akin to terrestrial continental flood basalt provinces. Entrainment of incompatible trace element enriched upper mantle in an otherwise deeply-derived incompatible trace element depleted mantle plume head in Mars at 180 million years ago may explain the similar crystallization ages of both enriched shergottites and some intermediate shergottites.

Jérôme Gattacceca¹ et al. (>10)
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14374]
¹CNRS, Aix Marseille Univ, IRD, INRAE, CEREGE, Aix-en-Provence, France
Published by arrangement with John Wiley & Sons

Meteoritical Bulletin 113 contains the 3646 meteorites approved by the Nomenclature Committee of the Meteoritical Society in 2024. It includes 17 falls, 2964 ordinary chondrites, 218 HED, 158 carbonaceous chondrites (including 7 ungrouped), 59 lunar meteorites, 38 iron meteorites (9 ungrouped), 30 ureilites, 31 primitive achondrites (3 ungrouped), 28 mesosiderites, 24 enstatite chondrites, 21 martian meteorites, 24 ungrouped stony achondrites, 20 Rumuruti chondrites, 17 pallasites, 8 angrites, 5 enstatite achondrites (one ungrouped), and 1 ungrouped chondrite. Of the meteorites approved in 2024, 1250 were collected in Antarctica, 1102 in Africa, 689 in Asia, 575 in South America, 17 in North America, 11 in Europe, and 2 in Oceania.

D. Das¹ et al. (>10)
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14375]
¹Los Alamos National Laboratory, Los Alamos, New Mexico, USA
Published by arrangement with John Wiley & Sons

The aim of this work is to provide a model-backed hypothesis for the formation of evaporites—sulfates, borates—in Gale crater using thermochemical modeling to determine constraints on their formation. We test the hypothesis that primary evaporites required multiple wet–dry cycles to form, akin to how evaporite assemblages form on Earth. Starting with a basalt-equilibrated Mars fluid, Mars-relevant concentrations of B and Li were added, and then equilibrated with Gale lacustrine bedrock. We simulated the cycles of evaporation followed by groundwater recharge/dilution to establish an approximate minimum number of wet–dry cycles required to form primary evaporites. We determine that a minimum of 250 wet–dry cycles may be required to start forming primary evaporites that consist of borates and Ca-sulfates. We estimate that ~14,250 annual cycles (~25.6 k Earth years) of wet and dry periods may form primary borates and Ca-sulfates in Gale crater. These primary evaporites could have been remobilized during secondary diagenesis to form the veins that the Curiosity rover observes in Gale crater. No Li salts form after 14,250 cycles modeled for the Gale-relevant scenario (approximately 10⁶ cycles would be needed) which implies Li may be leftover in a groundwater brine after the time of the lake. No major deposits of borates are observed to date in Gale crater which also implies that B may be leftover in the subsequent groundwater brine that formed after evaporites were remobilized into Ca-sulfate veins.

Kees C. WELTEN¹, Marc W. CAFFEE², Kevin RIGHTER^3,4, Ralph P. HARVEY^5,6, John SCHUTT⁵, and James M. KARNER⁷
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14376]
¹Space Sciences Laboratory, University of California, Berkeley, California, USA
²Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana, USA
³ARES, Mail Code XI2, NASA Johnson Space Center, Houston, Texas, USA
⁴Department of Earth and Environmental Sciences, University of Rochester, Rochester, New York, USA
⁵Department of Earth, Environmental and Planetary Science, Case Western Reserve University, Cleveland, Ohio, USA
⁶Antarctic Search for Meteorites (ANSMET), Case Western University, Cleveland, Ohio, USA
⁷Geology & Geophysics, University of Utah, Salt Lake City, Utah, USA
Published by arrangement with John Wiley & Sons

We reevaluated pairing relationships among 56 Antarctic howardites, eucrites, and diogenites (HED) from the Miller Range ice fields (MIL) based on new measurements of cosmogenic radionuclides and bulk composition of 28 HED samples and one HED-related dunite. These measurements were combined with petrographic examinations and find locations of the majority of the HED samples at MIL. During these studies, we reclassified 1 howardite, MIL 07665, as a brecciated diogenite and eight howardites as brecciated eucrites. We conclude that 18 of the 23 diogenites belong to a single large pairing group of brecciated diogenites. This pairing group includes at least seven samples with bulk compositions that indicate they contain 10%–25% of eucritic material, so technically the meteorites of this pairing group cross the boundary between diogenites and howardites. We also identified several smaller pairing groups (of 2–5 members each) among the eucrites and two paired samples among the howardites. The pairing relationships among the Miller Range eucrites are not fully resolved yet, as the collection contains many small specimens (<10 g) that were not included in this study. Altogether, we conclude that the 56 HED meteorites at Miller Range represent between 19 and 26 individual falls.

L. C. CHAVES^1,2*, M. S. THOMPSON², C. A. DUKES³, M. J. LOEFFLER⁴, M. F. MARTINEZ-MOTTA⁵, H. VANNIER², B. H. N. HORGAN², N. SMITH⁶, and K. ARDREY⁶
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14371]
¹Lunar and Planetary Laboratory, The University of Arizona, Tucson, Arizona, USA
²Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, USA
³Laboratory for Astrophysics and Surface Physics, University of Virginia, Charlottesville, Virginia, USA
⁴Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, Arizona, USA
⁵Departamento de Geociencias, Facultad de Ciencias, Universidad de los Andes, Bogota, Colombia
⁶Materials Science and Engineering, University of Virginia, Charlottesville, Virginia, USA
Published by arrangement with John Wiley & Sons

Pentlandite (Fe, Ni)₉S₈ is an important accessory mineral on asteroidal surfaces. It has been identified in returned regolith samples from asteroids Itokawa, Ryugu, and Bennu. Currently, systematic studies to understand the response of this mineral phase under space weathering conditions are lacking. In this work, we performed pulsed laser irradiation to simulate micrometeoroid impacts, and ion irradiation with 1 keV H⁺ and 4 keV He⁺ to simulate solar wind exposure for pentlandite. To understand the chemical, microstructural, and spectral alterations resulting from simulated space weathering, we conducted X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and reflectance spectroscopy across the visible to near-infrared wavelengths. Our results reveal S depletion and a change in the Fe:Ni ratio at the sample surface with continuing ion irradiation. Ion irradiation also created compositionally distinct rims in the pentlandite samples, while laser irradiation produced a surface melt. Additionally, we identified hillocks protruding from the pentlandite rim after He⁺ irradiation. Our findings also show that laser and H⁺-irradiation cause the sample to brighten, while He⁺ ion irradiation causes darkening. The change in spectral slope for samples irradiated with the laser and He⁺ is minimal, while H⁺ causes the sample to redden slightly. This work will enable the identification of space weathering signatures on pentlandite grains present in the recently returned samples from asteroids Ryugu and Bennu.

^1,2R.H. Hewins et al. (>10)
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2025.05.037]
¹IMPMC, Sorbonne Université, MNHN, UMR CNRS7590, 75005 Paris, France
²EPS, Rutgers Univ., Piscataway, NJ 08854, USA
Copyright Elsevier

An understanding of the differences between ungrouped, or anomalous, and normal carbonaceous chondrites could provide information on the population of parent bodies required to explain a chondrite group and on first solid accretion and evolution in the outer protoplanetary disk. The CR chondrites are key in this respect, as they display a unique formation history that distinguishes them from other groups. They are known to have formed between 4.1 and 4.6 Myr after CAI, with two generations of chondrules. Northwest Africa (NWA) 14674 is a CR2 anomalous (CR2-an) chondrite with very similar oxygen isotope composition, dark inclusion (DI) content, and serpentine-magnetite matrix to Al Rais (CR2-an). Both are petrologic subtype 2.3 with fresh magnesian olivine, and partly altered ferroan olivine, pyroxene, and metal. Additionally, NWA 14674 contains residual GEMS-like material at the nanoscale within preserved moderately altered areas. DI and matrix in NWA 14674 are mineralogically similar but they have different fabrics, and matrix is more porous than both DI and fine-grained rims (FGR). Matrix has aligned framboidal magnetite aggregates swathing the chondrules, suggesting slight compaction of the chondrite. Some DI have inner chondrule fragments and concentric layers richer and poorer in magnetite, indicating formation as accretionary pellets and lapilli: they are pebbles rather than clasts. The framboidal magnetite abundance is consistent with an alkaline alteration fluid potentially due to NH3 ice mixed with the more common water ice, which implies late distal accretion. Comparison with the CR chondrites Bells (regolith-like) and NWA 801 (with high-pressure clasts) indicates that a complex history involving inward drift, disruption of the grandparent body, and reaccretion of debris along with chondrules, DI pebbles, and dust is required to explain CR chondrite formation. The diverse facies observed in CR chondrites may be explained by the formation of relatively large parent bodies, comprising distinct layers (core to regolith). Some material has been inherited from a chondritic protoplanet that formed during the oligarchic growth phase of planetary formation. Subsequently, this initial body underwent disruption and partial reaccretion into the CR parent body.

¹Wei Dai,¹Frédéric Moynier,¹Zheng-Yu,^1,2Linru Fang,³James M. D. Day,⁴Marine Paquet,¹Julien Siebert
Proceedings of the National Academy of Science of the USA (PNAS) 22, e2422726122 Link to Article [https://doi.org/10.1073/pnas.242272612]
¹Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, Paris 75005, France
²Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Copenhagen K DK-1350, Denmark
³Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0244
⁴Université de Lorraine, CNRS, Centre de Recherches Pétrographiques et Géochimiques, Nancy F-54000, France

The extent of moderately volatile elements (MVE) depletion and its effects on the Moon’s evolutionary history remain contentious, partly due to unintentionally biased sampling by the Apollo missions from the Procellarum KREEP Terrane. In this study, we analyzed the Zn and K isotope compositions of a series of lunar basaltic meteorites, which vary in Th content and are likely to represent a broader sampling range than previous studies, including samples from the far side of the Moon. Our findings indicate remarkably consistent Zn and K isotope compositions across all lunar basalt types, despite significant variations in Th content. This consistency suggests a relatively homogeneous isotopic composition of volatile elements within the Moon, unaffected by subsequent impact events that formed major basins. Our results suggest that the estimates of MVE abundance and isotopic compositions from the Apollo returned samples are likely representative of the bulk Moon, supporting a globally volatile-depleted lunar interior.

¹M. V. Goryunov,²G. Varga,²Z. Dankházi,¹A. V. Chukin,³I. Felner,⁴E. Kuzmann,⁴Z. Homonnay,¹R. F. Muftakhetdinova,¹V. I. Grokhovsky,¹M. I. Oshtrakh
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14363]
¹Institute of Physics and Technology, Ural Federal University, Ekaterinburg, Russian Federation
²Department of Materials Physics, Eötvös Loránd University, Budapest, Hungary
³Racah Institute of Physics, The Hebrew University, Jerusalem, Israel
⁴Laboratory of Nuclear Chemistry, Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary
Published by arrangement with John Wiley & Sons

A fragment of the Kayakent IIIAB iron meteorite was analyzed using optical microscopy, scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD), X-ray diffraction (XRD), magnetization measurements, and Mössbauer spectroscopy. Optical microscopy and SEM show the presence of (i) the pure α2-Fe(Ni, Co) grains, (ii) the γ-Fe(Ni, Co) phase grains, (iii) the γ-Fe(Ni, Co) rims around the α2-Fe(Ni, Co) phase areas, (iv) the cloudy zone (a mixture of the γ-FeNi(Co) and α2-Fe(Ni, Co) phases), (v) plessite structures, and (vi) schreibersite inclusions in the α-Fe(Ni, Co) phase. The α-Fe(Ni, Co) phase demonstrates the ε-structure αε-Fe(Ni, Co) with the presence of at least three different orientations of the αε-Fe(Ni, Co) microcrystals, as shown by EBSD. EDS indicates variations in the Ni concentrations in the following ranges: (i) ~5.4–7.2 atom% in the α-Fe(Ni, Co) phase, (ii) ~15–18 atom% in the α2-Fe(Ni, Co) phase, and (iii) ~29–47 atom% in the γ-Fe(Ni, Co) phase grains. Schreibersite inclusions contain ~23.5–23.6 atom% of P, ~45.1–46.5 atom% of Fe, and ~28.8–31.4 atom% of Ni. The presence of ~98.1 wt% of the α-Fe(Ni, Co) phase and ~1.9 wt% of the γ-Fe(Ni, Co) phase is found by XRD in the powdered sample, while schreibersite is detected by XRD in the surface of the section only. Magnetization measurements show ferromagnetic multiphase material and a magnetic saturation moment of 175 emu g−1. The room temperature Mössbauer spectrum of the powdered Kayakent IIIAB sample demonstrates six magnetic sextets related to the ferromagnetic α2-Fe(Ni, Co), α-Fe(Ni, Co), and γ-Fe(Ni, Co) phases and one singlet assigned to the paramagnetic γ-Fe(Ni, Co) phase. In addition, the Mössbauer spectrum shows six minor magnetic sextets associated with 57Fe in the M1, M2, and M3 sites in schreibersite and one minor doublet shape assigned to the superparamagnetic rhabdite microcrystals. The iron fractions in the detected phases can be roughly estimated as follows: (i) ~11.9% in the α2-Fe(Ni, Co) phase, (ii) ~75.6% in the α-Fe(Ni, Co) phase, (iii) ~5.7% in the disordered γ-Fe(Ni, Co) phase with Ni content of ~34–40 atom%, (iv) ~1.5% in the more ordered γ-Fe(Ni, Co) phase with a higher Ni content (~46–47 atom%), (v) ~0.5% in the paramagnetic γ-Fe(Ni, Co) phase (~29–33 atom% of Ni), (vi) ~3% in schreibersite, and (vii) ~2% in rhabdite.