Meteoritics & Planetary Science最新文献

{"title":"Textural coarsening as the cause for impact-melt like plagioclase crystal size distributions and subtle layering in high-Al basalt 14053","authors":"Stu Webb,&nbsp;Clive R. Neal,&nbsp;Bridget Guiza,&nbsp;James M. D. Day","doi":"10.1111/maps.14362","DOIUrl":"https://doi.org/10.1111/maps.14362","url":null,"abstract":"<p>High-Al Apollo 14 basalt 14053 has been identified as an endogenous partial melt product from the lunar interior based on geochemical analyses, specifically low abundances of highly siderophile elements, but exhibits textural characteristics similar to those of impact melts. Prior studies of this sample have described mineralogical differences between “interior” and “exterior” portions, which have been attributed to exposure at the lunar surface and subsequent metamorphism through subsolidus reheating within or in proximity to an impact-ejecta blanket. It has been demonstrated that quantitative textural analysis is a useful tool for distinguishing between lunar rocks altered by impact processes and those produced by endogenic magmatic processes. Such an approach is used in this study to analyze multiple thin sections cut from interior and exterior portions of 14053. The textural heterogeneity of plagioclase crystals among thin sections revealed in this study suggests that an impact-ejecta blanket likely impinged on the western side of 14053. This thermal metamorphism coarsened the plagioclase grains within that portion of 14053 so intensely that components diffused to form subtle layering and moderate textural heterogeneity that was quantifiable. These results also support previous conclusions that suggest the differences in reduction textures within this sample are due to the limited penetration depth of solar-wind implanted hydrogen prior to reheating. Thermal metamorphism can produce textural changes in lunar samples even if below the solidus temperature, such that the plagioclase texture of an endogenous basalt is sufficiently altered to that resembling an impact melt. These results highlight the significance of quantitative petrographic observations of lunar samples to reveal important petrogenetic information that has to be placed in proper spatial context to be understood.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"60 6","pages":"1411-1420"},"PeriodicalIF":2.2,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14362","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144292420","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":"Multiple CV chondrite lithologies in Camel Donga 003 (CK3): Implications for the CV and CK parent bodies","authors":"Elana G. Alevy,&nbsp;Tasha L. Dunn,&nbsp;Alexander N. Krot,&nbsp;Paul Cardon-Pilotaz,&nbsp;Juliane Gross","doi":"10.1111/maps.14358","DOIUrl":"https://doi.org/10.1111/maps.14358","url":null,"abstract":"<p>Camel Donga 003 (CD 003) was originally classified as a CK3 chondrite based on its coarse-grained matrix, Ni-rich sulfides, Cr-rich magnetite, and CK-like silicate mineralogy. However, after preliminary backscattered electron imaging and elemental mapping of a 400 mm² thin section of CD 003, subsequent mineral chemistry analysis confirmed that the sample is a fragmental breccia consisting of three oxidized CV lithologies. In the two largest lithologies, both mineralogically pristine and metasomatically altered refractory inclusions are commonly found in close proximity to one another. This suggests that brecciation and mixing of different lithologies in CD 003 occurred on a submillimeter scale. The least abundant lithology—an 8 × 3 mm clast—is distinguished from the other lithologies by its recrystallized matrix, poorly defined chondrules, and equilibrated olivine (Fa₄₂). The homogeneity of matrix and chondrule olivine indicates that this lithology has been metamorphosed to at least petrologic subtype 3.8 conditions. We can trace the provenance of our sample to the main mass of CD 003, which must contain the CK material described in its original classification. Therefore, the presence of the three oxidized CV lithologies suggests that CD 003 is the first CV/CK3 chondrite breccia.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"60 6","pages":"1336-1364"},"PeriodicalIF":2.2,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144291923","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":"A complete inventory of institutional and public meteorite collections in Switzerland","authors":"J. Eschrig,&nbsp;M. M. M. Meier,&nbsp;B. A. Hofmann","doi":"10.1111/maps.14361","DOIUrl":"https://doi.org/10.1111/maps.14361","url":null,"abstract":"<p>Museums and universities are important for collecting, maintaining, and curating meteorites. To make specimens known and available for research, inventorying and optimal curation are important. However, not all meteorite collections are well curated, especially in smaller institutions. During a 12-month project supported by the Swiss Confederacy under the “SwissCollNet” framework, we viewed, photographed, and inventoried all public and institutional meteorite collections in Switzerland. In total, the 27 collections contain 7616 specimens, derived from 3469 different meteorites. New, switched, and missing specimens were found in many collections. More than half of the collections contained specimens without inventory numbers and unknown or unofficial specimens, several of which could be assigned to a known meteorite fall or find during this project. The identification of switched or unknown samples was done using handheld X-ray fluorescence spectrometry and magnetic susceptibility measurements. In total, 201 specimens were attributed a preliminary classification. We demonstrate the importance of smaller collections, which often hold fragments of rare meteorite types. We underline how large-scale projects like the one presented here allow for unique data, for example, finding specimens missing from one collection in another. By tracking the origin of specimens using historic labels, we show that the history of meteoritics is reflected in the composition of the Swiss collections. During the inventorying process, several prehistoric and modern artifacts made of meteoritic material were found, underlining the potential of analyzing non-geological specimens in museums.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"60 6","pages":"1384-1410"},"PeriodicalIF":2.2,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14361","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144291924","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":"Oued Chebeika 002: A new CI1 meteorite linked to outer solar system bodies","authors":"J. Gattacceca,&nbsp;M. Gounelle,&nbsp;B. Devouard,&nbsp;J.-A. Barrat,&nbsp;L. Bonal,&nbsp;A. J. King,&nbsp;C. Maurel,&nbsp;P. Beck,&nbsp;M. Roskosz,&nbsp;J.-C. Viennet,&nbsp;D. Mukherjee,&nbsp;N. Dauphas,&nbsp;P. R. Heck,&nbsp;T. Yokoyama,&nbsp;K. López García,&nbsp;O. Poch,&nbsp;O. Grauby,&nbsp;C. S. Harrison,&nbsp;V. Vinogradoff,&nbsp;P. Vernazza,&nbsp;S. Tikoo,&nbsp;V. Vidal,&nbsp;P. Rochette,&nbsp;D. AuYang,&nbsp;D. Borschneck,&nbsp;J. Juraszek,&nbsp;B. Clark","doi":"10.1111/maps.14359","DOIUrl":"https://doi.org/10.1111/maps.14359","url":null,"abstract":"<p>CI1 chondrites are rare meteorites with high scientific value. In fact, they are the most chemically primitive meteorites and show evidence of intense parent-body aqueous alteration. They also share strong similarities with samples from Ryugu and Bennu asteroids returned by the JAXA Hayabusa2 and NASA's OSIRIS-REx missions. In this work, we present a detailed study of the Oued Chebeika 002 meteorite, a ~420 g CI1 chondrite found in Morocco in 2024. We describe its petrography, texture, and mineralogy, with a focus on clay mineralogy. We provide the bulk and mineral chemical composition, as well as the bulk oxygen, iron, and chromium isotopic compositions. Spectroscopic properties were studied by means of infrared and Raman spectroscopies. We also measured the density, grain density and magnetic properties. Our results confirm that Oued Chebeika 002 is a CI1 chondrite, with close similarities to the other five know CI1 chondrites, and samples from Ryugu and Bennu asteroids. Several lines of evidence indicate that Oued Chebeika 002 has suffered no significant terrestrial alteration. It is more pristine in that regard than Alais, Orgueil and Ivuna CI1 chondrites, and more similar to samples from asteroids Ryugu and Bennu. Subtle differences exist between Oued Chebeika 002 and other CI1 chondrites that cannot be accounted for by terrestrial alteration of the latter. For instance, olivine and calcite were not observed. It is also noteworthy that the magnetic mineral assemblage of Oued Chebeika 002 is significantly different from that of Alais, Ivuna and Orgueil, but undiscernible from that of Ryugu samples. Chromium and iron isotopic composition of Oued Chebeika 002 confirms that CI1 chondrites, like Ryugu samples, are distinct from meteorites belonging to the non-carbonaceous and carbonaceous isotopic groups and may have originated from the same region where ice giant planets and Oort Cloud comets were formed.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"60 7","pages":"1441-1479"},"PeriodicalIF":2.2,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14359","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144705459","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":"Correction to “Corundum ± Magnesium-Deltalumite ± Hibonite-Bearing Objects in the CH Chondrite Sayh Al Uhaymir 290”","authors":"","doi":"10.1111/maps.14364","DOIUrl":"https://doi.org/10.1111/maps.14364","url":null,"abstract":"<p>Ryazantsev, K.M., Krot, A.N., Ma, C., Ivanova, M.A., Lorenz, C.A. and Shcherbakov, V.D. (2024), Corundum ± magnesium-deltalumite ± hibonite-bearing Objects in the CH Chondrite Sayh al Uhaymir 290. <i>Meteorit Planet Sci</i>, 59: 2608–2621. https://doi.org/10.1111/maps.14238</p><p>Figures 5 and 6 were reversed. The order of the captions was correct.</p><p>We apologize for this error.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"60 6","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14364","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144291789","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":"Bulk major and trace element abundances of barred olivine chondrules: Evidence about the physicochemical conditions in their region of nebular formation","authors":"M. E. Varela,&nbsp;J. Roszjar,&nbsp;P. Sylvester,&nbsp;L. Garcia","doi":"10.1111/maps.14360","DOIUrl":"https://doi.org/10.1111/maps.14360","url":null,"abstract":"<p>Barred olivine (BO) chondrules are present in ordinary and carbonaceous chondrites. We focus on the bulk major and trace element abundance composition of BO chondrules from carbonaceous, unequilibrated ordinary, and Rumuruti chondrites. Their bulk Fe/(FeO + MgO) wt% content versus the FeO wt% in olivine was used to divide these objects into FeO-poor and FeO-rich BO chondrules. The trace element content of bulk BO chondrules reveals the absence of fractionation among the abundances of elements having different geochemical behavior (e.g. Yb and [La-Ce]). This points to the predominance of a cosmochemical (e.g. gas/liquid or gas/solid condensation) instead of a geochemical process determining their elemental abundances. In addition, their bulk trace element content provides evidence for the physicochemical conditions that prevailed in the solar nebula during their formation. In general, such nebular regions are governed by local redox variations coupled with overall falling temperatures. The bulk chemical composition of the studied BO objects (e.g., Mg/Si bulk) suggests a time scale in which FeO-poor BO chondrules formed first in a chondrule-forming region rich in refractory trace elements. The progressive removal of refractory phases (e.g., hibonite, fassaite, melilite) led to a nebular reservoir depleted in the very refractory elements (e.g., Zr and Y) in which the rare earth elements (REEs) tend to reach equilibrium with the chondritic reservoir. From such a reservoir, the FeO-rich BO chondrules could have formed and were subsequently processed by metasomatic exchange reactions that equilibrated their moderately volatile V and Cr around chondritic values. The observed chemical variations are only possible if the studied BO chondrules behave as open systems exchanging elements with the cooling vapor. The inferred local redox variations coupled with overall falling temperatures could have taken place during the evolution of a single heterogeneous nebular reservoir in which Fe-poor and FeO-rich BO chondrules formed.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"60 6","pages":"1365-1383"},"PeriodicalIF":2.2,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144292757","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":"Petrogenesis of the Rantila meteorite fall and implications for the origin of aubrites","authors":"Yash Srivastava,&nbsp;Amit Basu Sarbadhikari,&nbsp;Varsha M. Nair,&nbsp;Avadh Kumar,&nbsp;Yogita Kadlag,&nbsp;Ramakant R. Mahajan,&nbsp;Neeraj Srivastava,&nbsp;Neha Panwar,&nbsp;Aditya Das,&nbsp;Ryoji Tanaka,&nbsp;James M. D. Day,&nbsp;Anil D. Shukla,&nbsp;Dwijesh Ray,&nbsp;Abhishek J. Verma,&nbsp;Alka Rani,&nbsp;Garima Arora,&nbsp;Dipak K. Panda,&nbsp;S. Vijayan,&nbsp;Anil Bhardwaj","doi":"10.1111/maps.14357","DOIUrl":"https://doi.org/10.1111/maps.14357","url":null,"abstract":"<p>Aubrites are rare meteorites from highly reduced differentiated parent bodies. The Rantila meteorite was recovered soon after falling on 17 August 2022 at Rantila and Ravel villages in Gujarat state, India. We report the petrography, mineralogy, chemical composition, oxygen- and chromium-isotope compositions, along with reflectance spectroscopy, all showing that Rantila is an aubrite. Coarse enstatite and diopside grains constitute the main mass of Rantila, while mm-wide fracture domains pervade the coarse enstatites. In the fractures, comminuted enstatite, diopside blebs, olivine, a plagioclase–silica assemblage, sulfides, and metals occur. Rantila consists of enstatite (&gt;85 vol%), diopside (~8 vol%), forsterite, albite, and silica along with various sulfides and Fe-Ni alloys. The concentration of rare earth elements is ~1–2 × CI, consistent with main group aubrites. Noble gas and nitrogen isotopic analyses reveal young exposure ages (13.81 ± 6.47 Ma), a heterogeneous nitrogen isotopic composition, and a major K-Ar resetting event around 3.2 ± 0.4 Ga in the parent body of Rantila. The bulk oxygen isotope values are within the range of aubrites. The chromium isotopic values of Rantila are consistent with main group aubrites. The mineral assemblages, texture, and crystallization modeling suggest that Rantila had an igneous origin. The mineral assemblages in fractures indicate the involvement of external melt possibly during an impact-fracturing event, which aligns well with the heterogeneous N isotopic composition. Additionally, Rantila shows a wider range of oxygen isotopes than other aubrites suggesting some extent of O isotopic heterogeneity, likely stemming from exogenous processes. The variation in intra-sample bulk O and N isotope values implies inherent heterogeneity within the main group aubrites, potentially caused by late-stage impact contamination.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"60 6","pages":"1318-1335"},"PeriodicalIF":2.2,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144292731","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":"Pairing and classification assessment of CM chondrites from the Meteorite Hills, Transantarctic Mountains","authors":"K. Righter,&nbsp;M. Welby,&nbsp;H. C. Bates,&nbsp;A. J. King,&nbsp;P. F. Schofield,&nbsp;J. Schutt,&nbsp;R. Harvey,&nbsp;J. Karner,&nbsp;B. Rougeux,&nbsp;K. Pando,&nbsp;C. Satterwhite","doi":"10.1111/maps.14353","DOIUrl":"https://doi.org/10.1111/maps.14353","url":null,"abstract":"<p>The Meteorite Hills dense collection area in the Transantarctic Mountains has yielded 1130 meteorites over several ANSMET field seasons. Twenty-three CM carbonaceous chondrites were recovered as part of the 2000–2001 and 2001–2002 field seasons. Many of these CMs have unique or rare features, but most are small (&lt;50 g), making their preservation of highest priority, so material can be available for future researchers. One major contributor to preservation is knowing which samples are paired with others. Because CM chondrites are fine grained and petrographic features are subtle, standard petrography is not as helpful in classification. To strengthen the understanding of pairing and classification, we initiated a focused study of the 23 CM chondrites recovered from Meteorite Hills. Combining magnetic susceptibility (MS), modal mineralogy as determined using X-ray diffraction (XRD), and published information about a subset of samples, we have reassessed the classification and pairing. Many samples have MS log <i>χ</i> values between 3.7 and 3.9, but there are a few exceptions such as MET 00432 (4.85), MET 01076 and 77 (4.06 and 4.63, respectively), and MET 01073 (3.21). Fifteen of the samples exhibit intermediate to high levels of aqueous alteration with phyllosilicate fractions (PSF) of 0.88–0.93. A trio of samples exhibit even higher levels of alteration with PSFs of 0.96–0.98. Find locations and cosmic ray exposure (CRE) ages of these two groups are similar and the latter very short at 0.1–0.2 Ma, raising the possibility that they are all part of the same heterogeneous fall. Since the three heavily altered samples are rare and have distinctive mineralogy relative to other MET CMs, they should be preserved regardless of whether they are from one large fall or two separate falls. Two samples (MET 01076 and MET 01077) contain a much greater fraction of olivine and pyroxene, have longer CRE ages, and most likely are heated CM chondrites. Three samples are unpaired and have unique characteristics: MET 00432 has a high magnetite fraction and other mineralogical and chemical properties comparable to C2 ungrouped chondrites such as Tagish Lake and Tarda, while MET 001087 (PSF = 0.77) and MET 00633 (PSF = 0.76) are less aqueously altered than the other meteorites, with the former in particular showing a significant tochilinite peak in its XRD pattern. Although MET 00633 could arguably be part of the larger pairing group of samples given its similar find location, we recommend keeping it unpaired given its distinct mineralogy.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"60 5","pages":"1249-1262"},"PeriodicalIF":2.2,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143930262","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":"Hydration and dehydration of CM chondrites revealed by X-ray diffraction combined with textural observations and compositional data","authors":"Naoya Imae,&nbsp;Makoto Kimura,&nbsp;Akira Yamaguchi","doi":"10.1111/maps.14348","DOIUrl":"https://doi.org/10.1111/maps.14348","url":null,"abstract":"<p>The in-plane rotation method is used to obtain X-ray random diffraction (XRD) patterns of polished thin sections of 10 CM chondrites. The samples include five intermediately altered CM chondrites with subtypes 2.6–2.3, two heavily altered CM chondrites with subtype 2.0 and three with secondary heating after hydration (Y 980036, Y 980051, and Jbilet Winselwan). These CM chondrites are compared to each other as well as four previously analyzed CM meteorites of subtypes 3.0–2.8 and 2.0. The same thin sections also underwent textural observations and compositional analyses. Unheated CM chondrites display systematic mineralogical changes. As the alteration degree increases from subtypes 3.0–2.0, the presence of olivine and clinoenstatite decreases, while that of serpentines increases. The abundance of tochilinite significantly increases from 2.7 to 2.3 but then decreases from 2.3 to 2.0. Subtype 2.0 consists of relatively more Mg-rich serpentine than Fe-rich serpentine (cronstedtite). The XRD identified only Mg-serpentine from Jbilet Winselwan, suggesting selective decomposition of Fe-rich serpentine (cronstedtite), while all hydrous minerals in Y 980036 and Y 980051 decomposed. Additionally, all three CM chondrites with secondary heating after hydration show stage II or category B heating by the peak metamorphic temperature of 300–750°C. Compared to previous studies using XRD, the combination of XRD with the textural and compositional analyses using the same polished thin section, avoiding the preparation for powder samples, is a straightforward approach to characterize hydrated chondritic samples. The approach is nondestructive and can be correlated with SEM/EPMA, unlike previous XRD studies that required powdered samples.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"60 5","pages":"1194-1215"},"PeriodicalIF":2.2,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14348","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143930505","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":"Evidence for phosphate metasomatism in an olivine-rich achondrites","authors":"Robert W. Nicklas,&nbsp;Melody Z.-A. Chen,&nbsp;Evan J. Saltman,&nbsp;Ethan F. Baxter,&nbsp;Andrew J. Lonero,&nbsp;Anthony B. Love","doi":"10.1111/maps.14356","DOIUrl":"https://doi.org/10.1111/maps.14356","url":null,"abstract":"<p>Brachinites, brachinite-like achondrites (BLA), and other similar primitive achondrites offer important constraints on differentiation processes of the earliest formed planetesimals, as they quenched amidst early differentiation processes on their parent body. Geochemical data for all major mineral phases in two previously poorly characterized meteorites, El Medano (EM) 395 and Northwest Africa (NWA) 12532, show that while EM 395 is a typical brachinite, NWA 12532 is more unusual, containing a high abundance of non-equilibrated apatite (1.26%) likely formed by a late-stage metasomatic event. These new data demonstrate that metasomatism by a P-Cl-Ca-rich fluid probably occurred on the brachinite parent body. This metasomatism may have occurred either during normal cooling of the asteroid or during later impact-related heating, consistent with the late formation of apatite in the paired andesitic achondrites Graves Nunatak (GRA) 06128 and 06129. These conclusions highlight that, while magmatism on small parent bodies ceased shortly after solar system formation, subsolidus processes may have continued much longer, and that metasomatism must be considered when interpreting bulk rock geochemical signatures of primitive achondrites.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"60 6","pages":"1302-1317"},"PeriodicalIF":2.2,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14356","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144292854","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}