Petrology, Geochemistry, and Geochronology of the L6 Ordinary Chondrite Maoming Meteorite

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1Cheng Yue, 1Xiaohao Che, 1Tao Long, 2Ziyao Wang, 1Huimin Wang, 1Chen Wang, 1Dunyi Liu
Acta Geoscientica Sinica (in Press) Link to Article [DOI: 10.3975/cagsb.2026.032421]
1Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China
2Hebei GEO University, Hebei, Shijiazhuang, 052161, China

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Characterization of Northwest Africa 6410 L6 ordinary chondrite using scanning electron microscopy, X-ray diffraction and Mössbauer spectroscopy

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1A. A. Maksimova, 1E. V. Petrova, 1A. V. Chukin, 2G. Varga, 2Z. Dankházi, 1,3,4M. Gritsevich, 5E. Kuzmann, 5Z. Homonnay, 1M. I. Oshtrakh
Meteoritics & Planetary Science, (in Press), 1–15 Link to Article [DOI: 10.1111/maps.70258]
1Institute of Physics and Technology, Ural Federal University, Ekaterinburg, Russian Federation
2Department of Materials Physics, Eötvös Loránd University, Budapest, Hungary
3Instituto de Astrofísica de Andalucía (IAA-CSIC), Granada, Spain
4Finnish Fireball Network, Ursa Astronomical Association, Helsinki, Finland
5Laboratory of Nuclear Chemistry, Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary

Published by arrangement with John Wiley & Sons

Ordinary chondrites preserve important information on the mineralogical and phase evolution as well as thermal metamorphism of their parent bodies. Quantitative characterization of minerals/phases and cation distributions in silicates using complementary analytical techniques provides valuable constraints on their crystal chemistry and thermal history. In this study, we investigate the Northwest Africa (NWA) 6410 L6 ordinary chondrite using optical microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and 57Fe Mössbauer spectroscopy. Optical microscopy revealed significant porosity of the polished section together with abundant chondrules and chondrule relics. The mineralogical/phase composition and crystal chemistry of the meteorite were characterized by SEM, EDS, XRD, and Mössbauer spectroscopy. XRD identified the major mineral phases, whereas Mössbauer spectroscopy resolved the Fe-bearing mineral/phase compounds and the distribution of Fe2+ between the M1 and M2 crystallographic sites in olivine and orthopyroxene. The occupancies of Fe2+ and Mg2+ at the M1 and M2 sites were determined from XRD refinements, while the ratios of Fe2+ site populations in silicates were derived from Mössbauer spectra. The Fe2+ M1/M2 site-occupancy ratios obtained independently by XRD and Mössbauer spectroscopy are in good agreement, demonstrating the consistency of the two approaches. The temperatures of cation equilibrium distribution calculated from XRD and Mössbauer spectroscopy are 570 and 626 K, respectively, for olivine and 679 and 686 K, respectively, for orthopyroxene. Classification based on the relative spectral areas (roughly the relative Fe fractions) of characteristic Mössbauer components confirms that NWA 6410 belongs to the L group of ordinary chondrites.

Distribution and rare earth element abundances of apatite in Bennu samples determined by synchrotron X-ray fluorescence spectroscopy

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1B. J. Tkalcec (>10)
 Meteoritics & Planetary Science, (in Press), 1–23
Open Source Link to Article [DOI: 10.1111/maps.70259]
1Schwiete Cosmochemistry Laboratory, Goethe University, Frankfurt am Main, Germany

Published by arrangement with John Wiley & Sons

Apatite is often the most rare earth element (REE)-enriched mineral in chondritic meteorites. REE enrichment and fractionation levels in apatite grains can give insight into the aqueous fluids in which they formed and the conditions prevailing within the host body. In this study, we applied synchrotron X-ray fluorescence (SXRF) spectroscopy to investigate the distribution and REE enrichments of 34 apatite grains in five rock fragments from asteroid (101955) Bennu, collected and brought to Earth by NASA’s OSIRIS-REx mission. We observe a strongly heterogeneous apatite distribution with frequent occurrence of clusters containing three to nine apatite grains. SXRF results reveal a wide grain-to-grain range of REE enrichment levels, at 15–900 times those of bulk CI chondrites. Of the 34 measured apatite grains, four are Mn-enriched (Mn > 1.26 wt%) and these show the lowest REE concentrations (15–65 times CI). Little light/heavy REE fractionation is observed in the Bennu apatite grains, in contrast to the heavy REE enrichment observed in apatite grains in samples from asteroid Ryugu. Our results suggest fluid circulation in Bennu’s parent asteroid involved apatite precipitation in cavities and local variations in water-rock interaction leading to local changes in fO2, and fluid chemistry. Given the dynamically evolving fluid conditions and the enhanced peripheral luminescence and oscillatory zoning observed in some apatite grains, an absence of REE fractionation during apatite formation appears unlikely. We postulate that, as fluid chemistry evolved to higher alkalinity and salinity, sequential complexation resulted in early incorporation of light REEs into precipitating apatite grains, subsequently balanced by later adsorption of heavy REEs.

Influence of minerals on aldose formation during hydrothermal processes in meteorite parent bodies

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1,2Taiyu Fujii, 1,2Shunpei Abe, 3Naoki Hirakawa, 1,2Kensei Kobayashi, 2Yoko Kebukawa
 Progress in Earth and Planetary Science (in Press)
Open Access
Link to Article [DOI: 10.1186/s40645-025-00793-5]
1Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan
2Department of Earth and Planetary Sciences, Institute of Science Tokyo, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
3Department of Education, Osaka Kyoiku University, 4-698-1 Asahigaoka, Kashiwara-shi, Osaka, 582-8582, Japan

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Behavior of the magnesium formate mineral during aqueous alteration of the Allende meteorite with organic compound–bearing fluid

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1Kanako Yoshihara, 2Hiroshi Isobe
Journal of Mineralogical and Petrological Sciences (in Press)
Open Acces Link to Article [DOI: 10.2465/jmps.250311]
1Graduate School Science and Technology, Kumamoto University, Kumamoto, 860–8555, Japan
2Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, 860–8555, Japan

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Mass-independent oxygen isotope fractionation driven by energetic-particle irradiation of icy solids

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1Gerardo Dominguez, 1Caroline Caplan, 1Lauren Tafla, 1Joshua Lucas, 2Ming-Chang Liu, 2Kevin McKeegan, 3Jeff Gillis
Proceedings of the National Academy of Sciences, 123, e2610806123
Open Access Link to Article [DOI: 10.1073/pnas.2610806123]
1Department of Physics, California State University, San Marcos, CA 92096-0001
2Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095-1567
3Department of Physics, Washington University of St. Louis, St. Louis, MO 63130

Mass-independent isotope fractionation (MIF) of oxygen provides key insights into atmospheric chemistry and the origin of isotopic anomalies in planetary materials. To date, MIF has been primarily associated with gas-phase processes involving symmetry-dependent reaction pathways, most notably ozone formation. Whether analogous effects can arise in condensed phases or at interfaces remains an open question. Here we report laboratory experiments demonstrating that energetic particle irradiation of icy oxide surfaces produces mass-independent oxygen isotope fractionation at temperatures as low as 10 K. Electron irradiation of SiO2 and Al2O3 substrates in the presence of H2O ice results in measurable shifts in Δ17O in the underlying solids. The resulting three-isotope relationships include slope-1-like behavior in SiO2 and Al2O3 and distinct, substrate-dependent trends in Al2O3, indicating that irradiation-induced defect formation and interfacial chemistry govern the isotope effects. The magnitude of the observed anomalies demonstrates that irradiation-driven processes can generate substantial oxygen isotope heterogeneity in condensed phases. These results identify a previously unrecognized class of MIF and provide a quantitative framework for interpreting oxygen isotope signatures in radiation-processed environments, including interstellar grains and early solar system materials.

A Martian meteorite that formed ≳4.1 billion years ago samples Mars’ early crust and mantle

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1,2Yang Liu et al. (>10)
Science (in Press) Link to Article [DOI: 10.1126/science.adz5646]
1Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
2Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA, USA

Reprinted with permission fromm AAAS

Martian meteorites provide a record of the planet’s geological history. However, most are geologically young samples that are not representative of Mars’ surface, which is dominated by ancient rocks. We describe the Martian meteorite Teghaza 001 (Teg 001), a slowly cooled igneous rock that formed at least 4.1 billion years ago. Its composition, mineralogy, and texture are distinct from other Martian meteorites. We determine that Teg 001 is a sample of ancient crust, which formed from a geochemically distinct mantle source with primordial composition. The presence of aqueously altered minerals, combined with bulk and mineral-specific oxygen isotope measurements, indicate that Teg 001 experienced reactions with fluids enriched in 18O, before ejection into space by an impact.