Meteoritics & Planetary Science最新文献

{"title":"Positive correlation between shock stage and petrologic type in ordinary chondrites: Implications for the internal structures and thermal histories of ordinary-chondrite parent asteroids","authors":"Alan E. Rubin","doi":"10.1111/maps.14284","DOIUrl":"https://doi.org/10.1111/maps.14284","url":null,"abstract":"<p>H, L, and LL chondrites all exhibit positive correlations between mean shock stage and petrologic type. At a given shock energy, hot samples exhibit more intense shock features than cold samples. After the ordinary-chondrite (OC) parent asteroids were collisionally disrupted, jumbled, and gravitationally reassembled, the correlations between mean shock stage and petrologic type may have resulted from stochastic collisions into material of different temperatures that were randomly distributed in the near-surface regions of the rubble-pile asteroids. Late-stage processes including shock events and post-shock annealing affected the preexisting correlations to only minor degrees. This model, combined with literature data, permits the following scenario: Each principal OC asteroid initially had an onion-shell structure with deeply buried type 6 materials cooling slowly, yielding young closure ages in Pb-phosphate data. The OC bodies were disrupted at ~60 Ma, locking in the Pb-phosphate record of the onion-shell structure. The H-chondrite parent body was collisionally disrupted somewhat later than the L or LL bodies and was thus somewhat cooler at the time of disruption. In the OC asteroidal rubble piles, materials of different petrologic types cooled at similar rates through ~500°C, precluding a correlation between petrologic type and metallographic cooling rate. Shortly after rubble-pile formation, materials of higher petrologic types remained hotter than materials of lower petrologic types. The hotter materials recorded more intense shock features from the common meteoroid flux, leading to positive correlations in each OC asteroid between petrologic type and mean shock stage. The cooler H-chondrite materials manifested a lower range in mean shock stage.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"60 1","pages":"17-31"},"PeriodicalIF":2.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14284","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143112967","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":"A Cryogenian impact structure lurking in the shadows of northern Sweden","authors":"C. Alwmark,&nbsp;G. G. Kenny,&nbsp;S. Alwmark,&nbsp;P. Minde,&nbsp;J. Plado,&nbsp;S. Hietala,&nbsp;M. J. Whitehouse","doi":"10.1111/maps.14280","DOIUrl":"https://doi.org/10.1111/maps.14280","url":null,"abstract":"<p>Here we report on findings for four rock samples with melt texture found in a gravel pit within a glaciofluvial deposit near the small town of Kitkiöjärvi in northernmost Sweden. The samples are comprised of granitic clasts embedded in a brown fine-grained melt matrix. The samples all contain quartz grains and/or clasts exhibiting multiple sets of planar deformation features oriented parallel to crystallographic planes characteristic of shock metamorphism. The samples also contain Former Reidite In Granular Neoblastic (FRIGN) zircon. We therefore conclude that the investigated samples represent impact melt rock. We interpret a U-Pb concordia age of 658.9 ± 6.9 Ma (Cryogenian) derived using secondary-ion mass spectrometry analysis of shocked zircon, as the best estimate for the age of the impact event that formed the melt rocks. Zircon grains from two of the samples yield younger lower intercept ages, raising the possibility that the samples came from multiple impact events of different ages. Although we cannot exclude this possibility, we interpret the younger ages from the clast-rich melt rocks to reflect non-impact-related Pb loss events and suggest that all samples likely came from the same structure. Analysis of the glaciofluvial history of the region, along with the relatively high frequency of finds (five in total, as one similar melt rock was found in the pit in 2018), points to a short-distance glacial transportation of the samples from the southwest. Since there are no known impact structures in Sweden within that area and/or of similar age, we conclude that an old (the oldest known yet) impact structure in Sweden potentially is yet to be discovered somewhere in the vicinity of the gravel pit.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"59 12","pages":"3305-3321"},"PeriodicalIF":2.2,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14280","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860226","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":"Shock petrographic and numerical modeling constraints on the morphology and size of the Morokweng impact structure, South Africa","authors":"Roger L. Gibson,&nbsp;S'lindile S. Wela,&nbsp;Auriol S. P. Rae,&nbsp;Marco A. G. Andreoli","doi":"10.1111/maps.14275","DOIUrl":"https://doi.org/10.1111/maps.14275","url":null,"abstract":"<p>The 369 m deep M4 drill hole, located ~18 km NNW of the center of the 146 Ma Morokweng impact structure (MIS), intersects shocked Archean granitoid gneisses and subsidiary dolerite intrusions that are cut by faults, cataclasites and mm- to m-wide suevitic and pseudotachylitic breccia dikes. The shock features in quartz in the gneisses and breccia dikes include decorated planar deformation features (PDFs), planar fractures, feather features, and toasting. Other minerals show features that may be shock-related, such as multiple sets of planar features and alternate twin ladder structures in feldspars, kink bands in biotite, and planar features in titanite, apatite, and zircon; however, these are variably annealed and/or overprinted by hydrothermal alteration effects, and confirmation of their origin awaits further study. Universal Stage measurements of PDF sets in quartz from 12 gneissic target rocks and from lithic and mineral clasts in three suevitic and three pseudotachylitic breccia dikes reveal four dominant sets: (0001), {<span></span><math>\u0000 <mrow>\u0000 <mn>10</mn>\u0000 <mover>\u0000 <mn>1</mn>\u0000 <mo>¯</mo>\u0000 </mover>\u0000 <mn>3</mn>\u0000 </mrow></math>}, {<span></span><math>\u0000 <mrow>\u0000 <mn>10</mn>\u0000 <mover>\u0000 <mn>1</mn>\u0000 <mo>¯</mo>\u0000 </mover>\u0000 <mn>4</mn>\u0000 </mrow></math>} and {<span></span><math>\u0000 <mrow>\u0000 <mn>10</mn>\u0000 <mover>\u0000 <mn>1</mn>\u0000 <mo>¯</mo>\u0000 </mover>\u0000 <mn>2</mn>\u0000 </mrow></math>}. Based on these observations, the average peak shock pressure in these rocks is estimated at ≤16 GPa, which supports the original proximity (within one transient cavity radius) of these rocks to the point of impact. No discernible depth-dependent shock attenuation was noted in the core. These shock levels and the elevated structural position of the rocks in the M4 core relative to the impact melt sheet intersected in drill holes closer to the center of the MIS suggest that the M4 lithologies represent part of the parautochthonous peak ring volume that subsequently experienced 1.5–2 km of post-impact erosion before it was buried beneath younger sediments. Numerical modeling using the iSALE-2D code suggests that the original Morokweng crater had a rim-to-rim diameter of between 70 and 80 km, and that the rocks in the M4 core were originally located at a depth of 7–8 km and a radial distance of 8–9 km from the point of impact.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"59 12","pages":"3250-3281"},"PeriodicalIF":2.2,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14275","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860144","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":"2018 Leonard Medal for Alexander N. Krot","authors":"Kevin D. McKeegan","doi":"10.1111/maps.14277","DOIUrl":"https://doi.org/10.1111/maps.14277","url":null,"abstract":"","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"59 12","pages":"E5-E6"},"PeriodicalIF":2.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859886","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":"Radial transport and nebular thermal processing of millimeter-sized solids in the Solar protoplanetary disk inferred from Cr-Ti-O isotope systematics of chondrules","authors":"Kohei Fukuda,&nbsp;Yuki Hibiya,&nbsp;Craig R. Kastelle,&nbsp;Katsuhiko Suzuki,&nbsp;Tsuyoshi Iizuka,&nbsp;Katsuyuki Yamashita,&nbsp;Thomas E. Helser,&nbsp;Noriko T. Kita","doi":"10.1111/maps.14276","DOIUrl":"https://doi.org/10.1111/maps.14276","url":null,"abstract":"<p>Understanding the material transport and mixing processes in the Solar protoplanetary disk provides important constraints on the origin of chemical and isotopic diversities of our planets. The limited extent of radial transport and mixing between the inner and outer Solar System has been suggested based on a fundamental isotopic dichotomy between non-carbonaceous (NC) and carbonaceous (CC) meteorite groups. The limited transport and mixing could be further tested by tracing the formation regions of individual meteoritic components, such as Ca-Al-rich inclusions (CAIs) and chondrules. Here, we show further evidence for the outward transport of CAIs and chondrules from the inner and subsequent thermal processing in the outer region of the protoplanetary disk based on the petrography and combined Cr-Ti-O isotope systematics of chondrules from the Vigarano-like (CV) carbonaceous chondrite Allende. One chondrule studied consists of an olivine core that exhibits NC-like Ti and O, but CC-like Cr isotopic signatures, which is enclosed by a pyroxene igneous rim with CC-like O isotope ratios. These observations indicate that the olivine core formed in the inner Solar System. The olivine core then migrated into the outer Solar System and experienced nebular thermal processing that generated the pyroxene igneous rim. The nebular thermal processing would result in Cr isotope exchange between the olivine core and CC-like materials, but secondary alteration effects on the parent body are also responsible for the CC-like Cr isotope signature. By combining previously reported Cr-Ti-O isotope systematics of CV chondrules, we show that some CV chondrules larger than ~1 mm would have formed in the inner Solar System. The accretion of the millimeter-sized, inner Solar System solids onto the CV carbonaceous chondrite parent body would require their very early migration into the outer Solar System within the first 1 million years after the Solar System formation.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"59 12","pages":"3282-3304"},"PeriodicalIF":2.2,"publicationDate":"2024-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14276","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142862165","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":"Curation and classification procedures for the UK Antarctic meteorite collection","authors":"J. L. MacArthur,&nbsp;K. H. Joy,&nbsp;R. H. Jones,&nbsp;T. A. Harvey,&nbsp;N. V. Almeida","doi":"10.1111/maps.14273","DOIUrl":"https://doi.org/10.1111/maps.14273","url":null,"abstract":"<p>The field of advanced curation is important for existing astromaterials collections, which includes samples returned by space missions, and meteorites and cosmic dust samples that have been recovered from here on Earth. In order to maximize the scientific return of the samples, contamination needs to be minimized at all stages of sample collection, preliminary examination, classification, and curation. Utilizing best practice methods, a detailed acquisition and curation plan was implemented during the UK's first two expeditions to collect Antarctic meteorites from two new blue icefields, Hutchison Icefields and Outer Recovery Icefields. This article documents the design and execution of the procedures used during the project's curation and classification processes. It describes two case studies showing the processes applied to the recovered meteorites, and reviews our experiences and lessons learned for the future.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"59 12","pages":"3215-3228"},"PeriodicalIF":2.2,"publicationDate":"2024-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14273","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142862164","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":"Experimentally induced troilite melt pervasion in chondritic analog materials: A study for FeNi-FeS darkening in chondrites","authors":"Juulia-Gabrielle Moreau,&nbsp;Argo Jõeleht,&nbsp;Aleksandra N. Stojic,&nbsp;Christopher Hamann,&nbsp;Felix E. D. Kaufmann,&nbsp;Peeter Somelar,&nbsp;Jüri Plado,&nbsp;Satu Hietala,&nbsp;Tomas Kohout","doi":"10.1111/maps.14274","DOIUrl":"https://doi.org/10.1111/maps.14274","url":null,"abstract":"<p>Iron sulfide and metal melt veins in chondritic materials are associated with advanced stages of dynamic shock. The shock-induced residual temperatures liquefy the sulfide component and enable melt distribution. However, the distribution mechanism is not yet fully understood. Capillary forces are proposed as agents of melt distribution; yet, no laboratory experiments were conducted to assess the role that capillary forces play in the redistribution of iron sulfide in post-shock conditions. To investigate this further, we conducted thermal experiments under reducing conditions (N₂(g)) using dunitic fragments, suitable chondritic analog materials that were doped with synthesized troilite (stoichiometric exact FeS). We observed extensive iron sulfide (troilite) migration that partially resembles that of ordinary chondrites, without the additional influence of shock pressure-induced fracturing. The iron sulfide melt infiltrated grain boundaries and pre-existing fractures that darkened the analog material pervasively. We also observed that the iron sulfide melt, which mobilized into grain boundaries, got systematically enriched in Ni from the surrounding host olivine. Consequently, FeNi metal fractionated from the melt in several places. Our results indicate that capillary forces majorly contribute to melt migration in the heated post-shock environment.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"59 12","pages":"3229-3249"},"PeriodicalIF":2.2,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142861961","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":"Differences in elemental abundances between CI chondrites and the solar photosphere","authors":"A. J. G. Jurewicz,&nbsp;A. M. Amarsi,&nbsp;D. S. Burnett,&nbsp;N. Grevesse","doi":"10.1111/maps.14272","DOIUrl":"https://doi.org/10.1111/maps.14272","url":null,"abstract":"<p>CI chondrites have been a proxy for the solar system since the mid-20th century. The photospheric and CI chondrite abundances (<b><i>P</i></b> and <b><i>CI</i></b>, respectively) show a strong correlation. <b><i>CI</i></b> as a proxy is also justified by the (i) smoothness of their abundances plotted as a function of odd mass number and (ii) agreement within the error of <b><i>P</i></b> as determined spectroscopically. But our statistical assessment of spectroscopic studies and solar wind from the Genesis mission indicates that the small, ~10%–30%, differences (residuals) between <b><i>CI</i></b> and <b><i>P</i></b> depend on the 50% condensation temperature (Tc₅₀). So, if <b><i>CI</i></b> is to be used as a proxy for <b><i>P</i></b>, Cosmochemists may want to add a correction to individual elements. Our work is consistent with two published hypotheses: that (i) residuals are linear with Tc₅₀ and (ii) that elements having Tc₅₀ &gt; 1343 K are depleted relative to those with 495 K &lt; Tc₅₀ &lt; 1343 K in <b><i>CI</i></b>. We discuss other interpretations which are also feasible. Understanding these small differences of the <b><i>CI</i></b> and <b><i>P</i></b> for different elements and their variation with Tc₅₀ can help constrain future models of solar system formation and the history of CI chondrites.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"59 12","pages":"3193-3214"},"PeriodicalIF":2.2,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14272","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142862024","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":"Ba and Sr isotopic patterns from step-leaching experiments on the pristine Aguas Zarcas CM2 meteorite","authors":"Liam S. T. McGovern,&nbsp;Bruce L. A. Charlier,&nbsp;Colin J. N. Wilson","doi":"10.1111/maps.14278","DOIUrl":"https://doi.org/10.1111/maps.14278","url":null,"abstract":"<p>Stepwise acid leaching experiments were performed on the pre-rain CM2 fall Aguas Zarcas to interrogate release patterns and isolate fractions with isotopic anomalies. Acid leachates and a bulk sample were analyzed for elemental abundances via solution ICP-MS, and Sr and Ba isotopic compositions were measured using TIMS. Isotopic systematics reveal diverse values for the bulk sample and leachates, interpreted to reflect the Aguas Zarcas parent body history. Compared with the NBS987 standard, μ⁸⁴Sr values for the bulk sample average + 90, while the leach fractions yield +326 to −2089, with the largest μ⁸⁴Sr depletions in the strongest acid leachates. For Ba isotopes, the bulk sample shows resolvable depletions (μ values) in ¹³⁰Ba (−210), ¹³⁵Ba (−64), ¹³⁷Ba (−73) and ¹³⁸Ba (−89). Early leachates show positive anomalies in ¹³⁰Ba (up to +2295), ¹³²Ba, ¹³⁵Ba, ¹³⁷Ba, and ¹³⁸Ba. In contrast, final leachates show strong depletions for the same nuclides (up to −60,000 ppm μ¹³⁰Ba). The Sr and Ba isotopic anomalies found in the earlier leachates suggest that nucleosynthetic signatures were redistributed to more soluble phases during parent body alteration. Moreover, contrasting <i>p</i>-nuclide Sr and Ba nucleosynthetic anomalies suggest that presolar contributions came from a variety of nucleosynthetic sources, including possibly a rotating massive star undergoing a core-collapse supernova or an electron capture supernova.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"59 12","pages":"3353-3369"},"PeriodicalIF":2.2,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142861727","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":"Constraints on the impact history of the Apollo 16 landing site: Implications of soil-like breccia noble gas records","authors":"M. C. Nottingham,&nbsp;N. M. Curran,&nbsp;J. Pernet-Fisher,&nbsp;R. Burgess,&nbsp;I. A. Crawford,&nbsp;J. D. Gilmour,&nbsp;R. Tartèse,&nbsp;K. H. Joy","doi":"10.1111/maps.14244","DOIUrl":"https://doi.org/10.1111/maps.14244","url":null,"abstract":"<p>The Apollo 16 regolith breccia sample suite provides a record of lunar regolith formation from the basin-forming epoch (~3.9 Ga) through to a time of declining impactor flux (~2 Ga). These rocks have been characterized into three groups: the “ancient,” “young,” and “soil-like” regolith breccias on the basis of their petrographic characteristics, and, in the case of the “ancient” and “young” regolith breccias, noble gas inventory. This study investigates the as-yet unexamined noble gas records of the “soil-like” regolith breccias to understand more recent regolith evolution processes that occurred at the Apollo 16 landing site. The range of gas concentrations measured for each noble gas in these samples is comparable to those previously reported for the local Apollo 16 soils. The “soil-like” regolith breccias were found to be more gas rich than the gas poor “young” and “ancient” regolith breccias, consistent with them having formed from comparatively mature soil(s). Our results further confirm the scientific value of lunar regolith breccias and bulk regolith samples as probes of the impact history and the space environment of the lunar surface across a wide range of time.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"59 11","pages":"2883-2921"},"PeriodicalIF":2.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14244","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142642016","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}