Meteoritics & Planetary Science最新文献

{"title":"Oxygen isotope thermometry and composition of aqueous fluids within the parent body of asteroid (101955) Bennu","authors":"Gary R. Huss,&nbsp;Kazuhide Nagashima,&nbsp;Elena Dobrică,&nbsp;Alexander N. Krot,&nbsp;Gregory Cane,&nbsp;Zoe E. Wilbur,&nbsp;Timothy J. McCoy,&nbsp;Catherine M. Corrigan,&nbsp;Sara S. Russell,&nbsp;Jessica J. Barnes,&nbsp;Ann N. Nguyen,&nbsp;Harold C. Connolly Jr.,&nbsp;Dante S. Lauretta","doi":"10.1111/maps.70231","DOIUrl":"https://doi.org/10.1111/maps.70231","url":null,"abstract":"<p>We report on the petrography and oxygen isotopic compositions from in situ analyses of carbonates (Ca-carbonate, dolomite, and Fe-rich magnesite), magnetite, and apatite in particles from asteroid Bennu. Using oxygen isotope thermometry of Ca-carbonate, dolomite, and magnetite, we estimated crystallization temperatures and the oxygen isotopic compositions of the aqueous fluids from which they precipitated. The Ca-carbonate–magnetite pairs formed at lower temperatures (−5 to 20°C) than the dolomite–magnetite pairs (5–89°C); the uncertainties are ±10–16°C. The inferred fluid compositions for Ca-carbonate–magnetite pairs are δ¹⁸O = 0.6‰–9‰ and Δ¹⁷O = 1.8‰–2.7‰, whereas for dolomite–magnetite pairs, they are δ¹⁸O = −2.2‰ to 7.6‰ and Δ¹⁷O = −0.1‰ to 0.9‰. On a three-isotope oxygen diagram (δ¹⁷O vs. δ¹⁸O), 11 out of 13 of our inferred aqueous fluid compositions plot along a single line with a slope of ~0.8, potentially indicating precipitation from a single isotopically evolving fluid. Two dolomite–magnetite pairs appear to be outliers and may have formed from fluids with different oxygen isotopic compositions. The oxygen isotope data presented herein overlap with those reported from samples of asteroid Ryugu, supporting a possible close genetic relationship between these asteroids.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 10","pages":"2567-2591"},"PeriodicalIF":3.2,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70231","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149177531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Zeolite formation via aqueous alteration of calcium-aluminum-rich inclusions on the CR and CV parent asteroids","authors":"M. A. Ivanova,&nbsp;S. N. Britvin,&nbsp;A. N. Krot,&nbsp;K. Nagashima,&nbsp;N. G. Zinovieva","doi":"10.1111/maps.70234","DOIUrl":"https://doi.org/10.1111/maps.70234","url":null,"abstract":"&lt;p&gt;We describe here zeolites and zeolite-like phases in Ca,Al-inclusions (CAIs) from Kaidun microbreccia and Northwest Africa (NWA) 3118 (CV3) chondrite studied using scanning electron microscopy (SEM), electron probe microanalysis (EPMA), secondary ion mass spectrometry (SIMS), Fourier transform infrared (FT-IR) spectroscopy, and single-crystal X-ray diffraction (SCXRD). Large (~4–8 μm in size) fragments of a coarse-grained igneous type B CAI from Kaidun consist of melilite (Åk&lt;sub&gt;35–75&lt;/sub&gt;), anorthite, magnesian spinel (&lt;1 wt% FeO), and Al,Ti-diopside (in wt%, TiO&lt;sub&gt;2&lt;/sub&gt; 4–18, Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; 16–22); perovskite, hibonite, and Fe,Ni-metal are minor. The CAI experienced aqueous alteration that resulted in replacement of melilite by the calcite + apophyllite [KCa&lt;sub&gt;4&lt;/sub&gt; (Si&lt;sub&gt;8&lt;/sub&gt;O&lt;sub&gt;20&lt;/sub&gt;) (OH,F)·8H&lt;sub&gt;2&lt;/sub&gt;O] + zeolites [natrolite (Na&lt;sub&gt;2&lt;/sub&gt;Al&lt;sub&gt;2&lt;/sub&gt;Si&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;10&lt;/sub&gt;·2H&lt;sub&gt;2&lt;/sub&gt;O)] and phillipsite-Na [(Na,K,Ca&lt;sub&gt;0.5&lt;/sub&gt;)&lt;sub&gt;4–7&lt;/sub&gt; (Al&lt;sub&gt;4–7&lt;/sub&gt;Si&lt;sub&gt;12−9&lt;/sub&gt;O&lt;sub&gt;32&lt;/sub&gt;)·12H&lt;sub&gt;2&lt;/sub&gt;O] assemblage previously unreported in meteorites. Oxygen isotopic composition of calcite is similar to that in CR chondrites (Δ&lt;sup&gt;17&lt;/sup&gt;O ~2‰, δ&lt;sup&gt;18&lt;/sup&gt;O ~41‰). Phillipsite and natrolite have Δ&lt;sup&gt;17&lt;/sup&gt;O close to that of calcite; the lack of proper SIMS standards for these minerals does not allow us to constrain their δ&lt;sup&gt;18&lt;/sup&gt;O values. These data and textural observations suggest co-precipitation of calcite and zeolites. Calcite–zeolite assemblages are commonly observed in terrestrial rocks that experienced aqueous alteration in the presence of low-temperature alkaline- and carbonate-rich solutions. We suggest that aqueous alteration and formation of calcite–zeolite–apophyllite assemblage in Kaidun CAI occurred in fractures, cracks, and veins from volatile-rich, alkaline hydrothermal fluids (pH = 8–10) at ~20–150°C. This alteration has little effect on oxygen and aluminum–magnesium isotope systematics of primary minerals in the Kaidun CAI: melilite, spinel, pyroxene, and anorthite have solar-like oxygen isotope compositions: Δ&lt;sup&gt;17&lt;/sup&gt;O = −22 to −25‰ and show resolvable excess of radiogenic &lt;sup&gt;26&lt;/sup&gt;Mg corresponding to the inferred initial &lt;sup&gt;26&lt;/sup&gt;Al/&lt;sup&gt;27&lt;/sup&gt;Al ratio [(&lt;sup&gt;26&lt;/sup&gt;Al/&lt;sup&gt;27&lt;/sup&gt;Al)&lt;sub&gt;0&lt;/sub&gt;] of (4.97 ± 0.11) × 10&lt;sup&gt;−5&lt;/sup&gt; (MSWD = 0.57; δ&lt;sup&gt;26&lt;/sup&gt;Mg*&lt;sub&gt;0&lt;/sub&gt; = 0.04 ± 0.05‰). Type C CAI from NWA 3118 consists of melilite (Åk&lt;sub&gt;18–56&lt;/sub&gt;, 0.1–0.3 wt% Na&lt;sub&gt;2&lt;/sub&gt;O), anorthite, Al,Ti-diopside (in wt%, TiO&lt;sub&gt;2&lt;/sub&gt; 3–5, Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; 16–24), and spinel (up to 3.3 wt% FeO). Melilite and anorthite in the peripheral part of the CAI are replaced by nepheline, sodalite, Na-bearing plagioclase, and hedenbergite. Melilite in the CAI core is replaced by a hydrated silica-rich amorphous phase, which may have been originally a zeolite that subsequently experienced structural and compositional changes dur","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 10","pages":"2505-2530"},"PeriodicalIF":3.2,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149177256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revisiting olivine-phyric shergottites: Pyroxene crystallization pressure and the role of undercooling","authors":"Roger H. Hewins,&nbsp;Brigitte Zanda,&nbsp;Arnaud Duverger","doi":"10.1111/maps.70220","DOIUrl":"https://doi.org/10.1111/maps.70220","url":null,"abstract":"<p>Shergottites are the most abundant meteorites from Mars and a major source of information on magma reservoirs, transport, and eruption, particularly in the late Hesperian northern hemisphere. Conflicting interpretations have arisen on the crystallization conditions of pyroxene in olivine-phyric shergottites. The pyroxene Ti:Al barometer suggested deep crustal or upper mantle crystallization, while 1 bar experimental petrology yielded a similar pyroxene Al-Ti distribution but suggested near surface formation. This barometer was first calibrated for alkali basalt, in which the phases that crystallized changed as a function of pressure, and it has not been demonstrated that its application could be extended to olivine-phyric shergottites. We have confronted this question by examining the petrogenesis of NWA 6234 and NWA 10170 olivine-phyric shergottites, which we confirm are paired. Modeling of their crystallization shows that the major-element composition trend of their composite, complexly zoned pyroxene crystals cannot be reproduced, indicating disequilibrium due to rapid cooling. It also shows that, with an unchanging sequence of crystallizing phases, the partitioning of Al and Ti into pyroxene does not change with pressure. Many olivine-phyric shergottites experienced strong undercooling, as in many Apollo and terrestrial basalts, consistent with surface eruption during pyroxene crystallization.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 10","pages":"2466-2475"},"PeriodicalIF":3.2,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70220","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149177299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cover","authors":"","doi":"10.1111/maps.70250","DOIUrl":"https://doi.org/10.1111/maps.70250","url":null,"abstract":"<p>\u0000 \u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure>\u0000 </p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 10","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70250","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149177456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-pressure phase preservation in ordinary L-chondrite melt veins: Evidence for control by post-shock thermal evolution","authors":"S. Effraimidou,&nbsp;I. Baziotis,&nbsp;M. Simopoulou,&nbsp;L. Ferrière,&nbsp;C. Sanchez-Valle,&nbsp;S. Klemme,&nbsp;J. Berndt,&nbsp;P. D. Asimow","doi":"10.1111/maps.70228","DOIUrl":"https://doi.org/10.1111/maps.70228","url":null,"abstract":"<p>This study investigates the petrography and mineralogy of three L-type ordinary chondrite meteorites: Northwest Africa (NWA) 4137 (L6), Homestead (L5), and Kunashak (L6). We studied the shock-related deformation features in the matrix and the characteristics of the melt veins, including the presence or absence of high-pressure (HP) phases. Our goal is to constrain the shock history of these meteorites, including constraints on peak shock conditions and on post-shock thermal histories. All three studied meteorites are strongly shocked, with textural evidence indicating shock stages up to S4 and development of melt veins. However, NWA 4137 is the only one of these meteorites in which HP phases were observed; we identified wadsleyite, majorite, albitic jadeite, tuite, and xieite within melt veins, indicating peak shock pressure in the range of 11–23 GPa. In contrast, the investigated melt veins in Homestead and Kunashak lack any HP phases despite indicators of comparable shock intensity to that observed in NWA 4137. The absence of HP phases in these two meteorites is attributed to a high post-shock temperature that favored back-transformation into low-P minerals during decompression over preservation of HP phases. These case studies testify to the importance of the full pressure (<i>P</i>)–temperature (<i>T</i>)–time (<i>t</i>) path experienced by meteoritic samples during shock events in determining their ultimate mineralogy.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 10","pages":"2549-2566"},"PeriodicalIF":3.2,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70228","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149177631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Description and terrestrial ages of the Calama Area Meteorite Collection (Atacama Desert, Chile)","authors":"Carine Sadaka,&nbsp;Jérôme Gattacceca,&nbsp;Florian Dumas,&nbsp;Régis Braucher,&nbsp;ASTER Team,&nbsp;Matthieu Gounelle,&nbsp;Dilyara Kuzina,&nbsp;Cyril Lorenz,&nbsp;Alexandre Corgne,&nbsp;Pierre Sempéré","doi":"10.1111/maps.70219","DOIUrl":"https://doi.org/10.1111/maps.70219","url":null,"abstract":"<p>We present a comprehensive study of a meteorite collection from the Atacama Desert (Chile), the driest and most climatically stable desert in the world. This collection includes meteorites from three adjacent Dense Collection Areas (DCAs) in the northern part of the Atacama Desert: Calama, Sierra Gorda, and Chug Chug, referred to as the “Calama area.” Within this region (~550 km²), we conducted a systematic search over a 2.5 km² zone in the Calama DCA and compared the resulting density to the nonsystematic recovery density in the Calama area. We also present the ³⁶Cl-based terrestrial ages of 49 ordinary chondrites selected from the Calama area. The systematic search yielded a meteorite recovery density of 38 meteorites per km² (15 meteorites per km² for meteorites &gt;20 g), and the collection exhibits a median terrestrial age of 303 ka. Notably, compared with the El Médano and Catalina DCAs, the Calama area is characterized by a lower meteorite density and younger meteorite terrestrial ages, most likely reflecting the region's more humid climate and more dynamic geomorphology due to its proximity to the pre-Andean range. Our results further show that meteorite weathering is not correlated with terrestrial age but is instead essentially controlled by the initial porosity of the meteorite, itself related to shock stage. Nevertheless, the Calama area still exhibits higher densities and older terrestrial ages than any other hot desert in the world, confirming that the long-term preservation of meteorites is observed across the entire Atacama Desert.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 10","pages":"2415-2430"},"PeriodicalIF":3.2,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70219","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149177190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Dingle Dell (L6) meteorite fall: In-depth characterization of an L chondrite with some LL-like properties originating from the inner main belt","authors":"Seamus L. Anderson,&nbsp;Gretchen K. Benedix,&nbsp;Lucy V. Forman,&nbsp;Luke Daly,&nbsp;Belinda Godel,&nbsp;Lionel Esteban,&nbsp;Matthias M.M. Meier,&nbsp;Colin Maden,&nbsp;Henner Busemann,&nbsp;Qing-Zhu Yin,&nbsp;Matthew E. Sanborn,&nbsp;Karen Ziegler,&nbsp;Jon M. Friedrich,&nbsp;Kees C. Welten,&nbsp;Marc W. Caffee,&nbsp;Kieren T. Howard,&nbsp;Hannah Mclain,&nbsp;Katarina Yocum,&nbsp;Daniel P. Glavin,&nbsp;Jason P. Dworkin,&nbsp;Robert Macke,&nbsp;Ashley F. Rogers,&nbsp;Hadrien A.R. Devillepoix,&nbsp;Phil A. Bland,&nbsp;Martin C. Towner,&nbsp;Eleanor K. Sansom,&nbsp;Alex W.R. Bevan","doi":"10.1111/maps.70232","DOIUrl":"https://doi.org/10.1111/maps.70232","url":null,"abstract":"<p>The Dingle Dell meteorite fell in the wheat belt of Western Australia on Halloween night (October 31st) in 2016 and was observed by multiple cameras from the Desert Fireball Network, being recovered less than a week later. In this paper, we report the in-depth characterization and reclassification of this meteorite, from its original LL6 class to an updated L6 chondrite. Dingle Dell is an unbrecciated L6 chondrite with low shock features (S2) and no weathering (W0). The silicate mineral chemistry is typical of an L chondrite (Fa = 24.4 ± 0.3; Fs = 20.5 ± 0.2; Wo = 1.6 ± 0.3; all mol%), while the kamacite-Co concentration is on the high end of the L-chondrite range. The measured oxygen isotopes (δ¹⁷O = 3.809 ± 0.068; δ¹⁸O = 5.102 ± 0.126; Δ¹⁷O = 1.115 ± 0.011) are slightly more consistent with an LL chondrite classification, though on the border shared by L and LL chondrites. The chromium isotopic anomaly measured in Dingle Dell also places it among both L and LL chondrites (ɛ⁵⁴Cr = −0.37 ± 0.09). Analyses of cosmogenic radionuclides and noble gases indicate that Dingle Dell existed as a small meteoroid (10–15 cm radius) for 9.3 ± 1.3 Myr before impacting the Earth. Ideal gas pycnometry indicates a grain density of 3.61 ± 0.01 g cm⁻³ and a bulk density of 3.23 ± 0.02 g cm⁻³, revealing a calculated porosity of 10.5% ± 0.5%. Dingle Dell's likely source region near the 3:1 mean motion resonance may constitute meteoritic sampling from an asteroid not associated with the Massalia or Flora families, the proposed sources for many L chondrites.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 10","pages":"2476-2504"},"PeriodicalIF":3.2,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149177416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimating past fluid pH and evaporative conditions in Gale crater using terrestrial analog samples from Death Valley, CA","authors":"D. Das,&nbsp;P. J. Gasda,&nbsp;K. Berlo,&nbsp;R. J. Leveille,&nbsp;M. A. Nellessen,&nbsp;L. Crossey,&nbsp;E. Peterson,&nbsp;R. Beal,&nbsp;A. L. Reyes-Newell,&nbsp;S. M. Clegg,&nbsp;N. L. Lanza,&nbsp;O. Gasnault","doi":"10.1111/maps.70237","DOIUrl":"https://doi.org/10.1111/maps.70237","url":null,"abstract":"<p>Boron and lithium have been observed in Ca-sulfate veins of Gale crater. These elements are highly water mobile and can inform us regarding the aqueous processes that may have taken place in Gale crater. However, the analysis of B in Gale crater is limited to low-Fe rocks and minerals due to spectral interference of Fe with B in ChemCam data. We investigate the distribution of B and Li in various phases (veins, sheet silicate mineral-rich sedimentary rocks, salts, and igneous materials) within samples collected from Death Valley and surrounding locations in Southern California, which we use as a terrestrial analog for Gale crater. In the terrestrial analog samples set that we study, B concentration is found to be predominantly associated with borate minerals while elevated Li concentration is linked with the presence of sheet silicate minerals. Based on these observations, we suggest that B enrichment as evaporites such as borates may have formed during evaporation of borate-enriched fluids in drier atmospheric conditions while Li enrichment may have taken place due to surface adsorption to sheet silicate minerals. Prior literature indicated that different fluid pH conditions and atmospheric humidity levels are necessary for borate enrichment and Li adsorption. The process of adsorption to the surface of sheet silicates is attributed to high pH aqueous conditions while the formation of borate minerals is attributed to a combination of low aqueous pH and high evaporative atmospheric conditions. We infer that the coexistence of borate minerals and Li-containing sheet silicates is indicative of multiple generations of aqueous conditions that likely took place over multiple seasonal cycles. We extend our inference to Gale crater and draw from the similarities between dry-lake deposits of Death Valley to provide a terrestrial-analog backed hypothesis on B and Li enrichment on Mars. We conclude that multiple early and late-stage aqueous events that may have involved the participation of groundwater activity were likely present to account for the observations in Gale crater.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 10","pages":"2531-2548"},"PeriodicalIF":3.2,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70237","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149177526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Localized alteration and contamination of lunar regolith particles upon exposure to Earth atmosphere","authors":"Zhi Cao,&nbsp;Pan Yan,&nbsp;Zhiyong Xiao,&nbsp;Yanxue Wu,&nbsp;Haiyang Xian,&nbsp;Yunhua Wu,&nbsp;Lifeng Zhong,&nbsp;Dengfeng Li,&nbsp;Mingchao Xiong,&nbsp;Zilei Chen","doi":"10.1111/maps.70229","DOIUrl":"https://doi.org/10.1111/maps.70229","url":null,"abstract":"<p>Microstructures on surfaces of lunar regolith particles record intricate processes during regolith formation and evolution. To acquire the complete morphology and composition of microstructures on surfaces of Chang'e-5 and Chang'e-6 regolith particles, the selected particles were rotated, cleaned using anhydrous ethanol, and loaded into electron microscopes for multiple rounds of analysis. During sample analysis, we noticed a few unusual features on the surfaces of the particles, including ferric-rich iron oxides and NaCl and KCl crystals. These features exhibit overlapping relationships with other microstructures, similar to those formed on the Moon. By comparing the before and after scanning electron microscope (SEM) images, we confirmed that these features resulted from the oxidation of metallic iron particles in the Earth atmosphere and the adhesion of terrestrial contaminants. Our results demonstrate that localized alteration and contamination of lunar regolith samples, although rare, may occur during a limited exposure to the Earth atmosphere, which might hamper interpretations of sample analysis. This work highlights the importance of full-process environmental protection (e.g., inert gas, constant temperature) for pretreatment, transfer and analysis of extraterrestrial samples.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 10","pages":"2431-2444"},"PeriodicalIF":3.2,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photochemical effects of Mars-like UV irradiation on carboxylic acids in carbonaceous chondrites and expectations for abiotic background organics on Mars","authors":"D. K. Buckner,&nbsp;J. C. Aponte,&nbsp;A. C. Schuerger,&nbsp;D. I. Foustoukos,&nbsp;F. Seguin,&nbsp;M. B. Wilhelm,&nbsp;G. Cooper,&nbsp;A. J. Williams","doi":"10.1111/maps.70194","DOIUrl":"https://doi.org/10.1111/maps.70194","url":null,"abstract":"<p>In the search for life on Mars, understanding the origin of preserved organics is critical. Expected sources include exogenous delivery, endogenous synthesis, and potentially life. Environmental processing by ultraviolet (UV) irradiation can alter these organics, obscuring hallmarks of their origin. To deconvolve these effects, we conducted an experimental study subjecting the Aguas Zarcas (CM2) carbonaceous chondrite to UV–VIS–NIR (200–2500 nm) irradiation under Mars environmental conditions (8.5 mbar pressure, −4 to −7 °C temperature, Mars atmosphere mix of 95.04% CO₂, 2.59% N₂, 1.94% Ar, 0.40% O₂, and 0.03% H₂O) for 154 sols (days on Mars) equivalent exposure. We measured changes to carboxylic acid abundances and compound-specific δ¹³C isotopes and bulk carbon, nitrogen, and hydrogen weight percent and isotopes. Compared to unirradiated samples, UV-exposed samples displayed nearly a twofold increase in total carboxylic acid abundance, due to elevated quantities of formic (C₁) and acetic (C₂) acids, while indigenous longer-chained (C₃–C₆) species displayed no change in abundance. Our results suggest that on Mars, UV irradiation of carbonaceous chondrites over short time scales is unlikely to degrade indigenous carboxylic acids and additionally may represent a photochemical synthesis mechanism for producing short-chain organic acids from meteoritic insoluble organic matter (IOM), meteoritic carbonates, or atmospheric CO₂ precursors.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 10","pages":"2445-2465"},"PeriodicalIF":3.2,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70194","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149177294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}