¹Felipe Abrahão Monteiro, ²Maria Elizabeth Zucolotto, ¹Amanda Araujo Tosi
Anuário do Instituto de Geociências (in Press)
Open Access Link to Article [DOI: 10.11137/1982-3908_2026_49_71839]
¹Universidade Federal do Rio de Janeiro, Instituto de Geociências, Departamento de Geologia, RJ, Rio de Janeiro, Brazil
²Universidade Federal do Rio de Janeiro, Museu Nacional, Departamento de Geologia e Paleontologia, Setor de Meteoritos, RJ, Rio de Janeiro, Brazil

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¹Kohei Fukuda
Japanese Magazine of Mineralogical and Petrological Sciences (in Press)
Open Access Link to Article [DOI: 10.2465/gkk.260113]
¹Forefront Research Center, Graduate School of Science, The University of Osaka, 1–1 Machikaneyama-cho, Osaka, Toyonaka, 560–0043, Japan

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^1,2Zhi-Peng Han, ^1,2De-Han Shen, ³Dong-Liang Zhang, ⁴Guang-Ming Song, ⁴Chuan Chen, ⁵Zi-Zheng Gong, ¹Shi-Jie Li
Bulletin of Mineralogy, Petrology and Geochemistry (in Press)
Link to Article [DOI: 10.3724/j.issn.1007-2802.20250040]
¹Center for Lunar and Planetary Sciences, Institute of Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
²University of Chinese Academy of Sciences, Beijing, 100049, China
³Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education, School of Geosciences and Info-physics, Central South University, Changsha, 410083, China
⁴Beijing Institute of Spacecraft Environment Engineering, Beijing, 100094, China
⁵Deep Space Exploration Lab., Beijing, 100089, China

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¹Yoko Kebukawa, ²Hiroki Suga, ^1,3Masanori Suzuki, ³Minori Ogino, ⁴Michael E. Zolensky, ⁵Yoshio Takahashi
Geochemical Journal (in Press)
Open Access Link to Article [DOI: 10.2343/geochemj.GJ26009]
¹Department of Earth and Planetary Sciences, Institute of Science Tokyo, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
²NanoTerasu Promotion Division, Japan Synchrotron Radiation Research Institute, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Miyagi, Sendai, 980-8572, Japan
³Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan
⁴Astromaterials Research and Exploration Science, NASA Johnson Space Center, Houston, 77058, TX, United States
⁵Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan

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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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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.

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.