^1,2S. Benaroya,^1,3,4,5J. Gross,¹P. Burger,⁶M. Righter,⁶T.J. Lapen,⁷S. Eckley
Geochimica et Cosmochimica Acta (in Press) Open Access Link to Article [https://doi.org/10.1016/j.gca.2024.02.004]
¹Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ, USA
²Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton Alberta, Canada
³Department of Earth and Planetary Sciences, American Museum of Natural History, New York, NY, USA
⁴Lunar and Planetary Institute, Houston, TX, USA
⁵Astromaterials Research and Exploration Science Division, NASA JSC, Houston, TX, USA
⁶Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA
⁷Jacobs – JETS, Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, TX, USA
Copyright Elsevier

Petrologic investigations of martian meteorite Northwest Africa (NWA) 13227 indicate it is an olivine-gabbroic shergottite, a relatively new shergottite group, which differs from previously described gabbroic shergottites due to relatively high quantities of olivine. NWA 13227 is comprised of phenocrystic, oscillatory-zoned pyroxene and olivine, set in a matrix of maskelynite, Fe-Cr-Ti oxides, phosphates, and sulfides. It displays gabbroic and poikilitic textures in 2D from back-scattered electron images, and in 3D from X-ray Computed Tomography (XCT) imaging, suggesting affinities to both poikilitic and gabbroic shergottites. Measured εHf and εNd values of bulk rock (-19.7 and −5.9, respectively) and its chondrite-normalized La/Yb ratio of 1.13 indicate the specimen is derived from a mantle reservoir relatively enriched in incompatible trace elements and is similar to that which produced most ‘enriched shergottites.’ Based on the Ti/Al ratio of pyroxene, phosphorous zoning in olivine, and minor components in phosphates and oxides, we infer that NWA 13227 began crystallizing under reducing conditions of QFM–2.6 and temperatures of ∼ 1100 °C, consistent with conditions in Mars’ lower crust/upper mantle. The sample finished crystallizing at or near the surface under redox conditions between QFM–0.5 to QFM–0.1 and temperatures of ∼ 850 °C. The volatile element compositions in apatite indicate that NWA 13227 experienced degassing during the last stages of crystallization. The timing of crystallization is estimated at 225 Ma ± 50 Ma using a Lu-Hf and Sm-Nd source versus age model.

¹Alexandra E. Doyle et al. (>10)
The Astrophysical Journal 950, 93 Open Access Link to Article [DOI 10.3847/1538-4357/acbd44]
¹Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095, USA

We present observations and analyses of eight white dwarf stars (WDs) that have accreted rocky material from their surrounding planetary systems. The spectra of these helium-atmosphere WDs contain detectable optical lines of all four major rock-forming elements (O, Mg, Si, and Fe). This work increases the sample of oxygen-bearing WDs with parent body composition analyses by roughly 33%. To first order, the parent bodies that have been accreted by the eight WDs are similar to those of chondritic meteorites in relative elemental abundances and oxidation states. Seventy-five percent of the WDs in this study have observed oxygen excesses implying volatiles in the parent bodies with abundances similar to those of chondritic meteorites. Three WDs have oxidation states that imply more reduced material than found in CI chondrites, indicating the possible detection of Mercury-like parent bodies, but are less constrained. These results contribute to the recurring conclusion that extrasolar rocky bodies closely resemble those in our solar system, and do not, as a whole, yield unusual or unique compositions.

^1,2Wang, Hongpeng,^1,3Xin, Yingjian,^1,3,4Fang, Peipei,^3,4Wang, Yian,^1,3Duan, Mingkang,⁵Wu, Wenming,⁶Yang, Ruidong,²Liu, Sicong ¹Zhang, Liang,^1,4Wan, Xiong
Chemosensors 11, 567 Open Access Link to Article [DOI 10.3390/chemosensors11110567]
¹Key Laboratory of Space Active Opto-Electronics Technology of the Chinese, Academy of Sciences, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
²College of Surveying and Geo-Informatics, Tongji University, Shanghai, 200092, China
³University of the Chinese Academy of Sciences, Beijing, 100049, China
⁴Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
⁵Geological Brigade 105, Bureau of Geology and Mineral Exploration and Development of Guizhou Province, Guiyang, 550018, China
⁶College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China

We currently do not have a copyright agreement with this publisher and cannot display the abstract here

¹Liam D. Peterson,¹Megan E. Newcombe,²Conel M.O’D. Alexander,²Jianhua Wang ,^3,4Sune G. Nielsen
Geochimica et Cosmochimica acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2024.02.002]
¹Department of Geology, University of Maryland, College Park, MD 20740, United States
²Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, United States
³NIRVANA Labs, Woods Hole Oceanographic Institution, Woods Hole, MA 02540, United States
⁴Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02540, United States
Copyright Elsevier

The abundance of H in planetary building blocks is of fundamental importance for constraining the evolution of the terrestrial planets. It is commonly assumed that chondrites are the principal sources of Earth’s H; however, recent studies have suggested that primitive achondrites and achondrites may retain a small complement of H. There are few constraints on the H budgets of primitive achondrites, which represent the transition from unmelted to melted planetesimals, but prior work suggests that bulk parent body H contents are several orders of magnitude lower than typical chondritic values. Therefore, to provide further constraints on H retention during the transition from unmelted to melted planetesimals, we have measured the H contents of olivine, orthopyroxene, clinopyroxene, and plagioclase from a suite of acapulcoite-lodranite clan meteorites. Acapulcoite-lodranite clan meteorites represent the “prototypical” primitive achondrite parent body and have bulk major element compositions more akin to the Earth than previously studied primitive achondrites (e.g., the ureilites). We find that the H2O contents of olivine (∼5–12 µg/g H2O), orthopyroxene (∼3–10 µg/g H2O), and clinopyroxene (∼5–8 µg/g H2O) are broadly similar, while plagioclase (∼2.5–5 µg/g H2O) tends to be offset to lower values. Using a simple, single-stage batch-melting model, we calculate a preferred maximum acapulcoite-lodranite parent body H2O content of 38 µg/g, which is similar to other estimates for primitive achondritic and achondritic parent bodies. Furthermore, assuming chondrite-like precursor materials, our data are consistent with efficient loss of H prior to or during the onset of melting of early-formed planetesimals. This requires that Earth’s H-budget was dominated by building blocks that underwent minimal thermal processing.

¹K.Righter et al. (>10)
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14146]
¹NASA Johnson Space Center, Houston, Texas, USA
Published by arrangement with John Wiley & Sons

The Dominion Range (DOM) and Miller Range (MIL) dense collection areas (DCAs) have yielded more than 20 and 200 CO3 chondrites (carbonaceous chondrites of the Ornans chemical group), respectively, over multiple field seasons. Several samples have exhibited primitive characteristics and have been the focus of interest. With so many CO3s recovered from this area, a natural question is if there are multiple pairing groups (where pairing refers to two or more meteorites that are part of a single fall) and if there is additional primitive material that would interest the meteorite community. This comprehensive study looks at all samples using several approaches: field and macroscopic observations; magnetic susceptibility; Cr in ferroan olivine; bulk elemental and isotopic analysis of H, C, N, and noble gas analyses to determine cosmic ray exposure (CRE) ages. Magnetic susceptibilities (measured as logχ) for all samples correlate with their type II (i.e., FeO-rich) olivine Cr contents, with the most primitive CO3s (3.00) have logχ values near 5, while the higher grade CO3s have logχ values as low as 4.17. Altogether, there appear to be two distinct CO3 pairing groups and five other unpaired CO3s recovered at the Dominion Range: (a) the main DOM 08004 pairing group (16 specimens with a CRE age of 10–16 Ma), (b) the DOM 08006 group (2 specimens incl. DOM 10847 with a CRE age of 25 Ma), (c) DOM 14359 with a CRE age of 6 Ma, (d) DOM 18070 with a CRE age of 8 Ma (these two samples have similar ages but distinct trapped 20Ne contents), (e) DOM 10900 with a CRE age of 5.5 Ma, (f) DOM 18286 (with a CRE age of ~59 Ma), and (g) DOM 19034 (with a CRE age of ~43 Ma). There are three distinct age groupings of 3.00–3.05 COs, highlighting the diverse pristine CO3 materials present in the DOM area. There is one large MIL pairing group (MIL 07099; n = 199; 9–14 Ma CRE age where measured) and one smaller pairing group with distinctly lower Cr2O3 in type II olivines (8 samples of unknown CRE age), and five unpaired or unique CO3s. Notably, the large DOM and MIL pairing groups have 9–16 Ma exposure ages that could have been delivered in a single large fall event spanning ~200 km, two separate falls that were ejection paired, or two separate falls from two separate ejections. Finally, we recommend reclassifying several CO3 to CM2 based on new data and that from previous studies.

¹D. Fernandes,^1,2N. G. Rudraswami,¹M. Pandey,^1,2V. P. Singh
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14143]
¹National Institute of Oceanography (Council of Scientific and Industrial Research), Dona Paula, Goa, India
²Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
Published by arrangement with John Wiley & Sons

Fe-rich relict olivine grains are found in a small percentage of cosmic spherules, which are studied here to determine the nature of their precursors. We examined 128 Fe-rich relict olivine grains with Fa >10 mol% from 53 cosmic spherules of different types collected from Antarctica (Antarctica micrometeorites [AMM]) and deep-sea sediments (DSS) of the Indian Ocean. Fe-rich olivines identified in cosmic spherules are close analogs of type II chondrule olivines formed in the early solar system. The olivine analysis shows well-defined trends in molar Fe/Mn versus Fe/Mg with an affinity for ordinary and carbonaceous chondrites. The minor oxides in olivine are in ranges such as MnO ~0.1–0.8 wt%, Cr2O3 ~0–0.7 wt%, CaO ~0–0.6 wt%, and Al2O3 ~0–0.2 wt%, respectively. The chemical composition suggests that the precursors for these Fe-rich olivine-bearing cosmic spherules consist of ordinary chondrites (~21%–23%, AMM-DSS), carbonaceous chondrites (~17%–36%, AMM-DSS), and a large fraction overlapping both carbonaceous and ordinary chondrites (~41%–62% AMM-DSS). The elemental ratios Fe/Si/CI and Mg/Si/CI for the Fe-rich relict olivines ranging between the values 0.5–1.0 and 1.1–1.7 are compatible with IDPs, Comet 81P/Wild 2 as well as the Asteroid Itokawa and Ryugu, which are indistinguishable from carbonaceous and ordinary chondrites. In addition, pyroxene and olivine assemblages in their Fa versus Fs mol% show strong similarities to EOC chondrites. Our results on Fe-rich relict olivines show that these grains in cosmic spherules are less common than Mg-rich olivines, which show a narrow range of chemical compositions identical to those from ordinary chondrites and carbonaceous chondrites, indicating a supplementary contribution of an ordinary chondritic component to the micrometeorite source of dust.

¹Christian Vollmer,^2,3Demie Kepaptsoglou,^4,5Jan Leitner,²Aleksander B. Mosberg,^2,3Khalil El Hajraoui,⁶Ashley J. King,^6,7Charlotte L. Bays,⁶Paul F. Schofield,^8,9Tohru Araki,^2,10Quentin M. Ramasse
Nature Communications 15, 778 Open Access Link to Article [DOI
https://doi.org/10.1038/s41467-024-45064-x%5D
¹Institut für Mineralogie, Universität Münster, Münster, Germany
²SuperSTEM Laboratory, Keckwick Lane, Daresbury, UK
³School of Physics, Engineering and Technology, University of York, Heslington, UK
⁴Institut für Geowissenschaften, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
⁵Max Planck Institute for Chemistry, Particle Chemistry Department, Mainz, Germany
⁶Planetary Materials Group, Natural History Museum, London, UK
⁷Department of Earth Sciences, Royal Holloway, University of London, Egham, UK
⁸Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
⁹National Institutes of Natural Sciences, Institute for Molecular Science, UVSOR Synchrotron Facility, Okazaki, Japan
¹⁰School of Chemical and Process Engineering and School of Physics and Astronomy, University of Leeds, Leeds, UK

We currently do not have a copyright agreement with this publisher and cannot display the abstract here

¹R.M. Marshal,¹M. Patzek,¹O. Rüsch
Icarus (in Press) Open Access Link to Article [https://doi.org/10.1016/j.icarus.2024.115984]
¹Institut für Planetologie, Universität Münster, 48149 Münster, Germany
Copyright Elsevier

This study investigates the key role of boulders, particularly their surface texture, which are primary surface features on small airless planetary bodies, that serve as indicators to better understand the geological history and evolutionary processes undergone by the small bodies and their respective parent bodies. In particular, this study focuses on characterizing the unpolished surface of meteorite samples, which can be likened to the surfaces of boulders on small bodies. We use surface roughness metrics such as the mean (bidirectional) slope and a Hapke mean slope angle in order to characterize the surface texture of the samples. Furthermore, considering a fractal roughness of the surface we estimate the Hurst exponent and the associated scaling factor at an arbitrary scale of ~60 μm. We find that on the ~4 μm scale, the mean bidirectional slope and the mean Hapke slope are in the range of 20–40° and 15–35° respectively, with carbonaceous chondrites collectively exhibiting the lowest average value for both. Furthermore, we provide surface roughness measurements for a subsample of the Ryugu sample A0008, which is broadly in agreement with the measurements derived from MASCam data. This study also investigated intra-sample heterogeneities, specifically surface roughness variations between matrix and non-matrix components such as impact melt, shock veins, and chondrules. The results suggest that surface roughness variations exist between these components and the matrix, however, the amplitude of the variation is strongly influenced by the petrological homogeneity of the chosen region of interest.

¹A.-M. Seydoux-Guillaume,²T. de Resseguier,³G. Montagnac,⁴S. Reynaud,⁵H. Leroux,³B. Reynard,⁶A.J. Cavosie
Earth and Planetary Science Letters 628, 118587 Link to Article [https://doi.org/10.1016/j.epsl.2024.118587]

¹UJM-Saint-Etienne, LGL-TPE UMR5276 CNRS, 42023 Saint Etienne, France
²PPRIME, CNRS-ENSMA-Université de Poitiers, 1 avenue Clément Ader, Futuroscope, 86961, France
³ENSL, UCBL, UJM, CNRS, LGL-TPE, Univ Lyon, Lyon F-69007, France
⁴UJM-Saint-Etienne, CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, Université de Lyon, Saint-Etienne F-42023, France
⁵CNRS, INRAE, Centrale Lille, UMR 8207 – UMET – Unité Matériaux et Transformations, Univ. Lille, Lille F-59000, France
⁶The Space Science and Technology Centre (SSTC) and the Institute for Geoscience Research (TIGeR), School of Earth and Planetary Science, Curtin University, Perth, WA 6102, Australia
Copyright Elsevier

Impact-related damage in minerals and rocks provides key evidence to identify impact structures, and deformation of U-Th-minerals in target rocks, such as monazite, makes possible precise dating and determination of pressure-temperature conditions for impact events. Here a laser-driven shock experiment using a high-energy laser pulse of ns-order duration was carried out on a natural monazite crystal to compare experimentally produced shock-deformation microstructures with those observed in naturally shocked monazite. Deformation microstructures from regions that may have experienced up to ∼50 GPa and 1000 °C were characterized using Raman spectroscopy and transmission electron microscopy. Experimental results were compared with nanoscale observations of deformation microstructures found in naturally shocked monazite from the Vredefort impact structure (South Africa). Raman-band broadening observed between unshocked and shocked monazite, responsible for a variation of ∼3 cm−1 in the FWHM, is interpreted to result from the competition between shock-induced distortion of the lattice, and post-shock annealing. At nanoscale, two main plastic deformation structures were found in experimentally shocked monazite: mosaïcism, and deformation bands. In contrast, the naturally shocked monazite sample, contained only deformation twins with elemental enrichment along host-twin boundaries. Both mosaicism and deformation bands, expressed in SAED patterns as streaking of spots, and the presence of extra spots (more or less pronounced), are proposed as nano-scale signatures of shock metamorphism in monazite. Experimentally calibrated deformation features, such as those documented here at TEM-scale, provide new tools for identifying evidence of shock deformation in natural samples.

¹Guido Jonker,²Flore van Maldeghem,³Matthias van Ginneken,²Lisa Krämer Ruggiu,²Steven Goderis
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14145]
¹Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
²Archaeology, Environmental Changes, and Geo-Chemistry, Vrije Universiteit Brussel, Brussels, Belgium
³Centre for Astrophysics and Planetary Science, School of Physical Sciences, University of Kent, Canterbury, UK
Published by arrangement

Cosmic dust particles originate from a wide variety of solar system and interstellar objects, including sources not identified among meteorite collections. Particles that survive atmospheric entry are retrieved on the Earth’s surface as micrometeorites. The recovery of these micrometeorites has recently advanced to rooftop sites. Here, we present the results of an extensive isotopic study on this type of rooftop micrometeorite from the Budel collection, the Netherlands, accreted to the Earth between October 31, 2018 and June 16, 2021. The triple oxygen isotopic compositions of 80 silica-dominated cosmic spherules (CSs) with diameters ranging between 105 and 515 μm are obtained relying on 213 in situ spot analyses determined using ion microprobe. Our analyzed population spans a large range of isotopic compositions and is dominated by carbonaceous chondritic sources. In situ measurements on several CSs support a possible continuum between 16O-rich and 16O-poor compositions following the CM mixing line, showing that 16O-poor CSs may be genetically related to aqueously altered carbonaceous chondrites. We demonstrate that weathering in the terrestrial environment has negligible effects on the isotopic compositions of the studied CSs and attempt to quantify the effects of kinetic mass-dependent fractionation and admixture of terrestrial oxygen during atmospheric entry. The results further corroborate previously suggested relations between CS texture and the duration and intensity of the heating pulse experienced during atmospheric deceleration. Finally, the young and well-constrained terrestrial age of the collection provides insights into the most recent flux of cosmic dust. Our results indicate no major recent changes in the global flux compared with collections sampled over thousand- to million-year time scales and demonstrate that 16O-poor material is still represented in the modern-day cosmic dust flux at a relative abundance of ~13%–15%. As such, rooftop micrometeorites represent a valuable reservoir to study the characteristics of the contemporary cosmic dust flux.