^1,2Lucie Riu,^2,3John Carter,²François Poulet
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2021.114809]
¹Institut of Space and Astronautical Science (ISAS), Japanese Aerospace eXploration Agency (JAXA), Sagamihara, Japan
²Institut d’Astrophysique Spatiale (IAS), Université Paris-Saclay, Orsay, France
³Laboratoire d’Astrophysique de Marseille (LAM), Marseille, France
Copyright Elsevier

This paper is the third paper of a series that provides the modal mineralogy of the Martian surface (M3 project) at the global scale using near-infrared hyperspectral imagery. Numerous locations at the surface of Mars have previously been identified to harbor hydrated minerals which offer unique insights on the past water activity at the red planet. A radiative transfer model has been used to reproduce the spectra of these locations, based on the OMEGA instrument (Observatoire pour la Minéralogie, l’Eau, les Glaces et l’Activité). Here we present the methodology applied to derive the hydrated quantitative composition and the first global compositional maps of hydrated minerals at Mars. Millions of spectra have been modelled to extract the modal composition of the hydrated locations, excluding sulfate-rich units. The lithology is summarized with 11 compositional maps of hydrated minerals at global scale at a sub-kilometer resolution. The hydrated mineralogy is dominated by an end-member of Fe-hydroxide, Fe- and Al-phyllosilicates and Fe/Mg micas which have on average an abundance >6 vol% and are spread globally on the identified regions. Locally, spots with high abundance (>20 vol%) of Al-smectite and Chlorite are also identified. The abundance of hydrated minerals is highest in Marwth Vallis, Nili Fossae and Meridiani Planum. However, the primary minerals almost always account for more than 50% of the composition. The modelling offers an opportunity to do local analysis of prospective landing sites and prepare for the upcoming landed missions. In the landing site for the ExoMars2022 and Mars2020 rovers, the obtained composition is in agreement with the expected detected mineralogy which demonstrates the robustness of the model and also offers a representation of the compositional variability. These global maps open the way to follow-up studies that will provide an in-depth characterization of the compositional gradients in local settings. Additionally, these compositional maps can 1) be used to calculate the water content namely potential amount of water stored within the quantified minerals and 2) provide information about the ISRU potential.

^1,2Y. Boleaga,^2,3,4M. K. Weisberg,^4,5J. M. Friedrich,^3,4D. S. Ebel
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13762]
¹City College, City University of New York, New York, New York, 10031 USA
²Department of Physical Sciences, Kingsborough College CUNY, Brooklyn, New York, 11235 USA
³Department of Earth and Environmental Science, CUNY Graduate Center, New York, New York, 10016 USA
⁴Department of Earth and Planetary Sciences, American Museum of Natural History, New York, New York, 10024 USA
⁵Department of Chemistry, Fordham University, Bronx, New York, 10458 USA
Published by arrangement with John Wiley & Sons

We present the results of our study of two thin sections of Pecora Escarpment (PCA) 91020, a heavily shocked EL3 chondrite, to characterize the sizes, shapes, orientations, and mineral compositions of its chondrules and opaque nodules. We also studied the mildly shocked Queen Alexandra Range (QUE) 94594 EL3 chondrite for comparison. PCA 91020 appears to show the evidence of deformation throughout the meteorite in both the chondrules and the opaque (metal–sulfide) nodules. Aspect ratios of the chondrules in PCA 91020 are greater than in the mildly shocked QUE 94594. Aspect ratios of the more ductile metal grains are higher than those of the chondrules in both sections of PCA 91020 and in QUE 94594. The data suggest that the chondrules and metal-rich nodules in PCA 91020 were elongated (flattened) to a greater degree and show a preferred orientation in comparison to objects in typical EL3 chondrites such as QUE 94594. The chondrule and metal-rich nodule deformation and foliation in PCA 91020 were likely produced by an impact on the EL3 asteroid. However, there are some inconsistencies in reconciling an impact hypothesis with all of the observations. Scenarios of hot accretion and/or overburden compaction during progressive (potentially rapid, hot) accretion to explain the deformation cannot be completely ruled out. Also, heavily shocked E3 chondrites, like PCA 91020, are relatively rare, suggesting the impacts that may have compacted chondrites, although potentially frequent, were of weak magnitude.

¹Nan Liu,²Nicolas Dauphas,^3,4Sergio Cristallo,^4,5Sara Palmerini,^4,5Maurizio Busso
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2021.11.022]
¹Department of Physics, Washington University in St. Louis, MO 63130, USA
²Origins Laboratory, Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, IL 60637, USA
³INAF, Osservatorio Astronomico d’Abruzzo, Via Mentore Maggini snc, 64100 Teramo, Italy
⁴INFN, Sezione di Perugia, Via A. Pascoli snc, 06123 Perugia, Italy
⁵Department of Physics and Geology, University of Perugia, Via A. Pascoli snc, I-06123 Perugia, Italy
Copyright Elsevier

Presolar oxide grains have been previously divided into several groups (Group 1 to 4) based on their isotopic compositions, which can be tied to several stellar sources. Much of available data was acquired on large grains, which may not be fully representative of the presolar grain population present in meteorites. We present here new O isotopic data for 74 small presolar oxide grains (∼200 nm in diameter on average) from Orgueil and Al-Mg isotopic systematics for 25 of the grains. Based on data-model comparisons, we show that (i) Group 1 and Group 2 grains more likely originated in low-mass first-ascent (red giant branch; RGB) and/or second-ascent (asymptotic giant branch; AGB) red giant stars and (ii) Group 1 grains with (26Al/27Al)0 ⪆ 5×10−3 and Group 2 grains with (26Al/27Al)0 ⪅ 1×10−2 all likely experienced extra circulation processes in their parent low-mass stars but under different conditions, resulting in proton-capture reactions occurring at enhanced temperatures. We do not find any large 25Mg excess in Group 1 oxide grains with large 17O enrichments, which provides evidence that 25Mg is not abundantly produced in low-mass stars. We also find that our samples contain a larger proportion of Group 4 grains than so far suggested in the literature for larger presolar oxide grains (≥ 400 nm). We also discuss our observations in the light of stellar dust production mechanisms.

¹N. G. Rudraswami,¹M. Pandey,²M. J. Genge,¹D. Fernandes
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13764]
¹CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004 India
²Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ UK
Published by arrangement with John Wiley & Sons

Bioavailable Fe is an essential nutrient for phytoplankton that enables the organisms to flourish and draw down atmospheric CO2 thus affecting global climatic conditions. In marine locales, remote from the continents, extraterrestrial dust provides an important source of Fe and thus moderates primary productivity. Here, we provide constraints on partitioning of extraterrestrial Fe between seawater and sediments from the observations of dissolution and the alteration of cosmic spherules recovered from deep-sea sediments and Antarctica. Of the ∼3000–14,000 t a−1 extraterrestrial dust that reaches Earth’s surface, ∼2–5% material falling in the oceans survives in marine sediments while the remainder is liberated into seawater. Both processes contribute ∼(3–10) × 10−8 mol Fe m−2 yr−1. The Fe contribution of surviving particles due to etching is estimated to be ∼10% of Fe contribution of meteoric smoke. Changes in extraterrestrial dust flux over geological time scales not only vary Fe delivery to the oceans by up to three orders of magnitude but also the partitioning of Fe between surface and abyssal waters depending on entry velocity and evaporation.

^1,2Atsushi Takenouchi,³Hirochika Sumino,⁴Karin Shimodate,²Akira Yamaguchi
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13768]
¹The Kyoto University Museum, Kyoto University, Yoshida-honmachi, Sakyo, Kyoto, 606-8501 Japan
²National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo, 190-8518 Japan
³General Systems Studies, Graduate School of Arts and Science, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902 Japan
⁴Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8654 Japan
Published by arrangement with John Wiley & Sons

LL chondrites have experienced multiple shock events; however, the relations of each shock event and their timing have rarely been investigated. To demonstrate the relations between each shock texture and shock chronological ages, we conducted both petrological and chronological (⁴⁰Ar/³⁹Ar and I-Xe ages) studies using aliquots subsampled from the same chip of the Northwest Africa (NWA) 2139 LL6 chondrite. Our ⁴⁰Ar/³⁹Ar studies and petrological observation reveal that NWA 2139 recorded at least three impact events before 4.17 ± 0.10 Ga, thus resulting in a complex brecciated texture, silicate darkening, and thick shock veins. An intense heating event occurred at 4.17 ± 0.10 Ga, which recrystallized the thick veins and healing cracks. Then, a weak shock event occurred at <3.9 Ga. Combined with ⁴⁰Ar/³⁹Ar data of other LL chondritic materials, this study supports that the LL chondrite parent body was possibly broken up by 1.7 Ga, and that most of the breakup likely occurred within 3.8–4.2 Ga.

¹Kassab, ²Ludovic Ferrière, ¹Djelloul Belhai
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13766]
¹Department of Geology, University of Sciences and Technologies Houari Boumediene, Algiers, Algeria
²Natural History Museum Vienna, Burgring 7, Vienna, A-1010 Austria
Published by arrangement with John Wiley & Sons

Tin Bider is a 6-km-diameter complex impact structure, the largest one recognized in Algeria. The crater was excavated in Cretaceous sedimentary rocks composed of, from the base to the top, Albian sandstones, Cenomanian clays, Cenomanian-Turonian limestones, undifferentiated Coniacian to Maastrichtian clays and limestones. The age of the impact event is poorly constrained to <66 Ma by stratigraphy, the youngest geological unit affected by the event being the ˜66 Myr old Maastrichtian limestones. Albian sandstones outcrop in the central sector of the structure and represent the only occurrence at outcrop of this geological unit in the structure. Here we report on a detailed petrographic analysis of eight Albian sandstone samples that were searched for shock-metamorphic features. We confirm the presence of rare shocked quartz grains with planar deformation features (PDFs) and report on their crystallographic orientations as determined using the universal stage microscope. PDFs oriented parallel to the π{10121} and ω{1013} orientations are the most abundant ones. For the first time in impactites from Tin Bider, PDFs with basal (0001) orientation, corresponding to amorphized mechanical Brazil twins, are reported. Our results indicate that locally the peak shock pressure was of at least 20 GPa, but much lower in average for the investigated samples.

^1,2P-M.Zanetta,¹C.Le Guillou,¹H.Leroux,^3,4B.Zandab,^2,3R.Hewins,¹G.Bellino
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2021.11.019]
¹Univ. Lille, CNRS, INRAE, Centrale Lille, UMR 8207 – UMET – Unité Matériaux et Transformations, F-59000 Lille, France
²IMPMC, Sorbonne Université, MNHN, UPMC Paris, UMR CNRS 7590, 75005 Paris, France
³EPS, Rutgers Univ., Piscataway, NJ 08854, USA
⁴Observatoire de Paris, IMCCE,75014 Paris, France
Copyright Elsevier

In order to understand the nature of the dust that accreted onto chondrules in the nebula and to unravel the conditions of formation of fine grained rims (FGRs), we studied three of the least altered chondrites from different chondrite groups (LL3.00 Semarkona, CO3.0 DOM 08006, CR2.8 QUE 99177) and compared the results with our previous work on the Paris CM chondrite (Zanetta et al., 2021). For each sample, we selected representative rimmed chondrules showing minimal traces of aqueous alteration. We performed high-resolution SEM X-ray chemical mapping to obtain relevant phase abundances and grain size distributions. Four FIB sections were then extracted from each meteorite, two in the rims and two in their adjacent matrix for quantitative TEM analysis. At the microscale, texture, modal abundances and grain size differ depending on the chondrite but also between FGRs and their adjacent matrix. At the nanoscale (i.e. TEM observations), matrices of the four chondrites consist mostly of domains of amorphous silicate associated with Fe-sulfides, Fe-Ni metal, Mg-rich anhydrous silicates and an abundant porosity. The related FGRs in Semarkona (LL) and DOM 08006 (CO) exhibit more compact textures with a lower porosity while FGRs in QUE99177 (CR) are similar to the matrix in terms of porosity. In the three chondrites, FGRs are made of smooth and chemically homogeneous amorphous (or nanocrystalline) silicate with no porosity that encloses domains of porous amorphous silicate bearing Mg-rich anhydrous silicates, Fe-sulfides, Fe-oxides and sometimes metal and Fe-rich olivines. The average compositions in major elements of the amorphous regions are similar for the FGRs and the matrix within a given chondrite (but differ between chondrites). The texture and the chemical homogeneity of the smooth silicate and the fact that it encloses domains of porous amorphous silicate bearing other mineral phases similar to matrix-like material suggests a formation by condensation. Areas that are enclosed in this smooth silicate exhibit Fe-rich olivine formed through Fe interdiffusion that also suggest a thermal modification of the dust accreted to form FGRs. These characteristics indicate a transformation process for the modification of the FGR material similar to the one proposed in our previous work on Paris. We conclude that matrix and FGRs accreted a similar type of dust but FGR material was affected by thermal modification and compaction contemporary with their accretion. For each chondrite, dust accreted onto chondrules under different conditions (dust density, temperature) which led to diverse degrees of compaction/thermal modification of the sub-domains and explain the textural differences observed in FGRs. They accreted on chondrules in a warm environment related to the chondrule formation episode, whereas matrix accreted later in a cooler environment.

¹E.Dobrică,¹K.K.Ohtaki,²C.Engrand
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2021.11.018]
¹Hawai‘i Institute of Geophysics and Planetology, School of Ocean, Earth Science, and Technology, the University of Hawai’i at Mānoa, Honolulu, Hawai‘i 96822 USA
²Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay Campus, France
Copyright Elsevier

We report detailed transmission electron microscope (TEM) observations of carbonates from one hydrated fine-grained Antarctic micrometeorite (H-FgMM). These carbonates show the occurrence of complex chemical variations and microstructures that provide important evidence regarding the formation and evolution of rarely analyzed H-FgMMs. The chemical variations were identified at both micrometer and nanometer scales, indicating that these carbonates formed under localized fluid conditions that suggest a variable chemical microenvironment. Individual carbonates grew from isolated reservoirs of fluid. Moreover, these carbonates contain manganese amounts almost twice as high as those measured in CM chondrites but similar to those identified in CI chondrites. Their particular compositions indicate reducing and progressively evolving conditions in the fluid from which these carbonates precipitated, probably due to water consumption during phyllosilicates formation. In addition to the compositional variability, microstructural features are pervasive in these carbonates, similar to those described in heavily shocked meteorites indicating that these carbonates were probably modified during shock processes after their formation. Since carbonates are highly susceptible to shock metamorphism, we suggest that it is essential to investigate their structure in detail before interpreting the isotopic measurements related to the time of their formation. Additionally, associated with carbonates, ubiquitous phosphates were identified in the micrometeorite analyzed. Future studies of these mineral associations will provide us further insight into the formation and evolution of asteroids, especially since they were both identified in the surface materials of Ryugu and Bennu.

¹Nicole Phelan et al. (>10)
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2021.11.020]
¹Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0244, USA
Copyright Elsevier

New ¹⁸⁷Re-¹⁸⁷Os, ⁸⁷Rb-⁸⁷Sr, triple O-isotope isotope, bulk rock highly siderophile- (HSE: Os, Ir, Ru, Pt, Pd, Re), major- and trace-element abundance data are reported for a variety of carbonaceous, ordinary and enstatite chondrite meteorites. In addition, new mineral chemical data are reported for the Chelyabinsk LL5 ordinary chondrite fall for comparison with existing chondrite data and to investigate element sequestration into metal and mineral phases within some chondrites. The focus of the study is to link the variations observed in the HSE abundances and Re-Os isotopes with other isotopic and elemental data to explore the relative roles of sample sizes, terrestrial alteration and parent body processes more fully on chondrite meteorite compositions. Trace element variations in Chelyabinsk silicate, oxide and metal grains highlight the importance of geochemical heterogeneity imparted by mineralogical variations and mode effects, as well as sample size. Using a range of sample powder aliquot sizes, it is possible to show that this becomes significant for the HSE at <0.1 g. Variations in high field strength elements relative abundances (HFSE: Ti, Zr, Nb, Ta, Hf) are also identified within individual aliquots of carbonaceous chondrite Ivuna, emphasizing the importance of complete dissolution of refractory phases. The range of fall and find meteorites examined here demonstrates that terrestrial alteration effects revealed for trace elements (e.g., Ba, U, Sr) do not correlate particularly well with Re/Os variations. Instead, the Re/Os ratios of carbonaceous chondrites are susceptible to disturbance, more so than indicated by incompatible trace element systematics, with the Murchison CM2 carbonaceous chondrite showing significant Re/Os fractionation between sample aliquots. For sample aliquots measured that do not show significant mode or terrestrial alteration effects, parent body processes appear to be largely restricted to thermal metamorphism and dehydration. Including data for this study, the combined published dataset for Re-Os isotope and HSE abundances now extends to 33 ordinary, 39 carbonaceous, 27 enstatite and 6 Rumuruti chondrites. The range in absolute HSE abundances among these meteorite groups is ∼30%, with all chondrites having, within uncertainties, the same average Os, Ir, Ru, Pt and Pd abundances. Notably, carbonaceous chondrites have long-term Re/Os ∼8% lower than for the other chondrite groups. If chondrite groups are representative of early planetary feedstocks, then the measured ¹⁸⁷Os/¹⁸⁸Os of ordinary chondrites make them a close match to the composition of the bulk silicate Earth. Assuming ∼0.5% late accretion of ordinary chondrites to Earth, this would result in a long-term Rb/Sr ratio ∼0.6% higher than from late accretion of carbonaceous chondrites, indicating that ordinary chondrites are a potentially attractive source for moderately volatile enrichment.

¹Sautter V.,^2,3Payre V.
Comptes Rendus – Geoscience 353, 64 Link to Article [DOI 10.5802/CRGEOS.64]
¹IMPMC-UMR, CNRS 7590, Sorbonnne Université, 61 rue Buffon, Paris, 75231, France
²Rice University, Houston, 77005-1892, TX, United States
³Department of Physics and Astronomy, Northern Arizona University, Flagstaff, 86011, AZ, United States

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