¹Yoko Kebukawa et al. (>10)
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115582]
Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
Copyright Elsevier

Primitive carbonaceous xenolithic clasts found in sturdy metamorphosed meteorites often provide opportunities to reach labile volatile-rich materials which are easily destroyed during atmospheric entry and materials which we do not have sampled as individual meteorites. Among them, a xenolithic carbonaceous clast in the Zag H3–6 ordinary chondrite has been providing us with the opportunity to analyze a possible sample from D/P-type asteroids. Here we performed a new suite of coordinated analyses of organic matter in the Zag clast using the atomic force microscope infrared spectroscopy (AFM-IR) combined with nanoscale secondary ion mass spectrometer (NanoSIMS), X-ray absorption near-edge spectroscopy (XANES) coupled with scanning transmission X-ray macroscope (STXM), Raman, and (scanning) transmission electron microscopy [(S)TEM] on adjacent ultramicrotomed thin sections from a single sample grain. We successfully demonstrated the practicality of coordinated analyses using AFM-IR, Raman and NanoSIMS on the same sample area, as well as STXM/XANES on adjacent (and nearly identical) thin sections to those used for AFM-IR. The AFM-IR map and STXM maps provided consistent and complementary results. We found that at least two types of organics were closely mixed in this specimen. One was deuterium-rich, Cdouble bondO rich organics with likely smaller aromatic domains, possibly originating in relatively oxidized environments from D-rich precursors. The other type was less deuterium-rich, but aromatic-rich organics, possibly produced in relatively reduced and higher temperature environments with less deuterium-rich precursors. These characteristics point to complex mixtures of materials with different origins and sampling a wide heliocentric range of the Solar System before accretion in the parent body of the clast.

¹B.E.Clark et al. (>10)
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115563]
Department of Physics and Astronomy, Ithaca College, Ithaca, NY, USA
Copyright Elsevier

This paper summarizes the evidence for the optical effects of space weathering, as well as the properties of the surface that control optical changes, on asteroid (101955) Bennu. First, we set the stage by briefly reviewing what was known about space weathering of low-albedo materials from telescopic surveys, laboratory simulations, and sample return analysis. We then look at the evidence for the nature of space weathering on Bennu from recent spacecraft imaging and spectroscopy observations, including the visible to near-infrared and thermal infrared wavelengths, followed by other measurements such as normal albedo measurements from LIDAR scans. We synthesize these different lines of evidence in an effort to describe a general model of space weathering processes and resulting color effects on dark C-complex asteroids, with hypotheses that can be tested by analyzing samples returned by the mission.

A working hypothesis that synthesizes findings thus far is that the optical effects of maturation in the space environment depend on the level of hydration of the silicate/phyllosilicate substrate. Subsequent variations in color depend on surface processes and exposure age. On strongly hydrated Bennu, in color imaging data, very young craters are darker and redder than their surroundings (more positive spectral slope in the wavelength range 0.4–0.7µm) as a result of their smaller particle sizes and/or fresh exposures of organics by impacts. Solar wind, dehydration, or migration of fines may cause intermediate-age surfaces to appear bluer than the very young craters. Exposed surfaces evolve toward Bennu’s moderately blue global average spectral slope. However, in spectroscopic and LIDAR data, the equator, the oldest surface on Bennu, is darker and redder (wavelength range 0.55–2.0
µm) than average and has shallower absorption bands, possibly due to dehydration and/or nanophase and/or microphase opaque production.

Bennu is a rubble pile with an active surface, making age relationships, which are critical for determining space weathering signals, difficult to locate and quantify. Hence, the full story ultimately awaits analyses of the Bennu samples that will soon be delivered to Earth.

¹A.Dugdale et al. (>10)
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115568]
¹AstrobiologyOU, School of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, United Kingdom
Copyright Elsevier

The phyllosilicate-bearing martian plain, Oxia Planum, is the proposed landing site for the Rosalind Franklin rover mission, scheduled to launch in 2028. Rosalind Franklin which will search for signs of past or present life on Mars. Terrestrial analogue sites and simulants can be used to test instruments analogous to those on Rosalind Franklin, however no simulant for Oxia Planum currently exists. In anticipation of this mission, a simulant – SOPHIA (Simulant for Oxia Planum: Hydrated, Igneous, and Amorphous) – representative of the local mineralogy at Oxia Planum has been developed for biosignature and mineralogy experiments, which will assist in interpreting data returned by the rover. The simulant is derived from orbital observations of Oxia Planum and its catchment area. As no in situ data is available for Oxia Planum, mineralogy from other comparable sites on Mars was used to design the simulant including orbital data from Arabia Terra and Mawrth Vallis and in situ data collected from Gale crater. The mineralogy, chemistry and physical properties of the simulant were characterised using standard laboratory techniques (SEM-EDS, XRF, XRD).Techniques analogous to rover instruments (Raman spectroscopy, Near-IR spectroscopy analogous to the Raman laser spectrometer and ISEM and MicrOmega instruments) were also used. The simulant is rich in Fe/Mg phyllosilicates with additional primary igneous and other alteration minerals and is an appropriate spectral and mineralogical analogue for Oxia Planum.

^1,2Dennis HARRIES,³Xuchao ZHAO,³Ian FRANCHI
Meteoritics & Planetary Science (in Press) Open Access Link to Article [doi: 10.1111/maps.13980]
¹Department of Analytical Mineralogy, Institute of Geoscience, Friedrich Schiller University Jena, Carl-Zeiss-Promenade 10,07745 Jena, Germany
²European Space Resources Innovation Centre, Luxembourg Institute of Science and Technology, 41 rue du Brill, L-4422Belvaux, Luxembourg
³School of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK
Published by arrangement with John Wiley & Sons

Hydroxyl defects in nominally anhydrous minerals (NAMs) were potential carriers ofwater in the early Solar System and might have contributed to the accretion of terrestrial water.To better understand this, we have conducted a nanoscale secondary ion mass spectrometrysurvey of water contents in olivine and orthopyroxene from a set of equilibrated ordinarychondrites of the L and LL groups (Baszk ́owka, Bensour, Kheneg Ljouˆad, and Tuxtuac) andseveral ultramafic achondrites (Zakøodzie, Dhofar 125, Northwest Africa [NWA] 4969, NWA6693, and NWA 7317). For calibration, we used terrestrial olivine and orthopyroxene with H2Ocontents determined by Fourier transform infrared. Our 99.7% (~3SD) detection limits are 3.6–5.4 ppmw H2O for olivine and 7.7–10.9 ppmw H2O for orthopyroxene. None of the meteoriticsamples studied consistently shows water contents above the detection limits. A few exceptionsslightly above the detection limits are suspected of terrestrial contamination by ferricoxyhydroxides. If the meteorite samples investigated accreted in the presence of small amountsof water ice, the upper limits of water contents provided by our survey suggest that the retentionof hydrogen during thermal metamorphism and differentiation was ineffective. We suggest thatloss occurred through combinations of low internal pressures, high permeability along grainboundaries, and speciation of hydrogen into reduced compounds such as H2and methane,which are less soluble in NAMs than in water.

^1,2Amanda Tosi et al. (>10)
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13976]
¹LABSONDA/IGEO/UFRJ, Instituto de Geociências, Universidade Federal do Rio de Janeiro, Av. Athos da Silveira Ramos, 274, Cidade Universitária, 21941-972 Rio de Janeiro, RJ, Brazil
²LABET/MN/UFRJ, Laboratório Extraterrestre, Departamento de Geologia e Paleontologia, Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brazil
Published by arrangement with John Wiley & Sons

On August 19, 2020, at 13:18—UTC, a meteor event ended as a meteorite shower in Santa Filomena, a city in the Pernambuco State, northeast Brazil. The heliocentric orbital parameters resulting from images by cameras of the weather broadcasting system were semimajor axis a = 2.1 ± 0.1 au, eccentricity e = 0.55 ± 0.03, and inclination i = 0.15o ± 0.05. The data identified the body as an Apollo object, an Earth-crossing object with a pericenter interior to the Earth’s orbit. The chemical, mineralogical, and petrological evaluations, as well as the physical analysis, followed several traditional techniques. The meteorite was identified as a H5-6 S4 W0 ordinary chondrite genomict breccia. The large amount of metal in the meteorite made a metallographic evaluation based on the opaque phases possible. The monocrystalline kamacite crystals suggest a higher petrological type and the distorted Neumann lines imply at least two different shock events. The absence of the plessite phase shows that the meteorite did not reach the highest shock levels S5 and S6. The well-defined polycrystalline taenite is indicative of petrologic types 4 and 5 due to the conserved internal tetrataenite rim at the boundaries. The presence of polycrystalline taenites and the characteristics of the Agrell Effect suggest that the Santa Filomena meteorite did not reheat above 700°C. The absence of martensite confirms reheating temperatures <800°C and a slow cooling rate. The Ni contents and sizes of the zoned taenite particles indicate a slow cooling rate ranging from 1 to 10 K Myr−1.

^1,2,3Fanny CATTANI,²Barbara A. COHEN,⁴Cameron M. MERCER,⁵Agnes J. DAHL
Meteoritics & Planetary Science 58, 591-611 Open Access Link to Article [doi: 10.1111/maps.13960]
¹The Catholic University of America, Washington, DC, USA
²Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
³Center for Research and Exploration in Space Science and Technology, NASA/GSFC, Greenbelt, Maryland, USA
⁴U.S. Geological Survey, Geology, Geophysics, Geochemistry Science Center, Denver, Colorado, USA
⁵Department of Earth Sciences, University of Gothenburg, Goteborg, Sweden
Published by arrangement with John Wiley & Sons

Several laboratories have been investigating the feasibility of in situ K-Ar dating foruse in future landing planetary missions. One drawback of these laboratory demonstrations isthe insufficient analogy of the analyzed analog samples with expected future targets. Wepresent the results obtained using the K-Ar laser experiment (KArLE) on two old and K-poorchondritic samples, Pułtusk and Hvittis, as better lunar analogs. The KArLE instrument useslaser ablation to vaporize rock samples and quantifies K content by laser-induced breakdownspectroscopy (LIBS), Ar by quadrupole mass spectrometry (QMS), and ablated mass by laserprofilometry. We performed 64 laser ablations on the chondrites to measure spots with a rangeof K2O and Ar content and used the data to construct isochrons to determine the chondriteformation age. The KArLE isochron ages on Pułtusk and Hvittis are 5059892 Ma and4721793 Ma, respectively, which is within the uncertainty of published reference ages, andinterpreted as the age of their formation. The uncertainty (2σ) on the KArLE ages obtained inthis study is better than 20% (18% for Pułtusk and 17% for Hvittis). The precision, whichcompares our obtained ages to the reference ages, is also better than 20% (11% for Pułtuskand 4% for Hvittis). These results are encouraging for understanding the limits of thistechnique to measure ancient planetary samples and for guiding future improvements to theinstrument.

¹Edward D. Young,²Anat Shahar,¹Hilke E. Schlichting
Nature 616, 306-311 Link to Article [DOI https://doi.org/10.1038/s41586-023-05823-0]
¹Department of Earth, Planetary, and Space Sciences, University of California Los Angeles, Los Angeles, CA, USA
²Carnegie Institution for Science, Earth and Planets Laboratory, Washington, DC, USA

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

¹Martin R. LEE,¹Cameron FLOYD,¹Pierre-Etienne MARTIN,²Xuchao ² A. FRANCHI,¹Laura JENKINS,¹Sammy GRIFFIN
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.13978]
¹School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK2School of Physical
²Sciences, Open University, Milton Keynes MK7 6AA, UK*Corresponding author.Martin R. Lee, School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK
Published by arrangement with John Wiley & Sons

LaPaz Icefield (LAP) 02239 is a mildly aqueously altered CM2 carbonaceouschondrite that hosts a xenolith from a primitive chondritic parent body. The xenolithcontains chondrules and calcium- and aluminum-rich inclusions (CAIs) in a very fine-grained matrix. The chondrules are comparable in mineralogy and oxygen isotopiccomposition with those in the CMs, and its CAIs are also mineralogically similar to the CMpopulation apart for being unusually small and abundant. The presence of serpentinedemonstrates that the xenolith has been aqueously altered, and its phyllosilicate-rich matrixhas a comparable oxygen isotopic composition to the matrices of CM meteorites. Thexenolith’s chondrules lack fine-grained rims, whereas the xenolith itself has a fine-grainedrim that is petrographically and chemically comparable with the rims on coarse grainedobjects in LAP 02239 and other CM meteorites. These properties show that the xenolith’sparent body was formed from similar materials to the CM parent body(ies). Following itslithification by aqueous alteration, a piece of the xenolith’s parent body was impact-ejected,acquired a fine-grained rim while free-floating in the protoplanetary disc, then was accretedalong with rimmed chondrules and other materials to make the LAP 02239 parent body.Subsequent aqueous processing of the LAP 02239 parent body altered the fine-grained rimson the xenolith, chondrules, and CAIs. The xenolith shows that the timespan of geologicalevolution of carbonaceous chondrite parent bodies was sufficiently long for some of them tohave been aqueously altered before others had formed.INTRODUCTIONThe Mighei-like (CM) carbonaceous chondrite (CC)meteorites have close spectroscopic affinities to C-complexasteroids (Burbine,2016) and so likely sample one or moreof them. The parent body(ies) of the CMs were formed bythe accretion of relatively coarse-grained objects (i.e.,chondrules and calcium- and aluminum-rich inclusions[CAIs]) together with fine-grained material that formsthe enclosing matrix (Barber,1981; McSween Jr. &Richardson,1977). The chondrules and other coarse-grainedobjects typically have fine-grained rims that they acquiredwhile free-floating in the protoplanetary disc (Hanna &Ketcham,2018; Metzler et al.,1992). The constituents of thecoarse-grained objects, fine-grained rims and matrix(anhydrous silicates, metal, sulfides, oxides, and amorphousmaterials) were partially to completely altered by parentbody aqueous activity at~4563 Ma (Bunch & Chang,1980;Fujiya et al.,2012; McSween Jr.,1979a,1979b). Theresultant secondary minerals are volumetrically dominatedby phyllosilicates that are intergrown with carbonates,oxides, and sulfides (Barber,1981; Bunch & Chang,1980;Fuchs et al.,1973;Howardetal.,2009,2011,2015;Leeet al.,2014; Tomeoka & Buseck,1985;Trigo-Rodrıguezet al.,2019; Zolensky et al.,1993).TheCMsareclassifiedby petrologic type/subtype using various properties thatMeteoritics & Planetary Science1–16 (2023)doi: 10.1111/maps.139781Ó2023 The Authors.Meteoritics & Planetary Sciencepublished by Wiley Periodicals LLC on behalf of The Meteoritical Society.This is an open access article under the terms of theCreative Commons AttributionLicense, which permits use,distribution and reproduction in any medium, provided the original work is properly cited.

¹K.Righter et al.(>10)
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13973]
¹NASA Johnson Space Center, Houston, Texas, USA
Published by arrangement with John Wiley & Sons

NASA’s OSIRIS-REx spacecraft collected samples from carbonaceous near-Earth asteroid (101955) Bennu on October 20, 2020, and will deliver them to the Earth on September 24, 2023. The samples will be processed at the NASA Johnson Space Center (JSC), where most of the sample collection will be subsequently curated in a new cleanroom suite. The spacecraft collected loose regolith two ways: in a bulk sample chamber capable of holding up to 2 kg, and on industrial Velcro “contact pads” intended to collect small particles at the surface. Included in the JSC collection will be the bulk sample, the contact pads, contamination-monitoring witness plates, and supporting hardware. Planning for the curation of the samples and hardware started at the earliest phase of proposal development and continued in parallel with project development and execution. Because a major mission goal is characterization of organic compounds in the Bennu samples, extra effort was spent in the design stage to ensure a clean curation environment. Here, we describe the preparations to receive the sample, including the design, construction, outfitting, and monitoring of the cleanrooms at JSC; the planned recovery of the sample-containing capsule when it lands on Earth; and the approach to characterizing and cataloging the samples. These curation efforts will result in the distribution of pristine Bennu samples from JSC to the OSIRIS-REx science team, international partners, and the global scientific community for years to come.

¹Secana P. GOUDY,¹Myriam TELUS,²Brendan CHAPMAN
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.13969]
¹Earth and Planetary Sciences, University of California, Santa Cruz, Santa Cruz, California, USA2School of Earth and Space Exploration, Arizona State University, Tempe, Arizona, USA
²Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064, USA
Published by arrangement with John Wiley & Sons

We examined H4 chondrites Beaver Creek, Forest Vale, Quenggouk, Ste. Marguerite, and Sena with the electron backscatter diffraction (EBSD) techniques of Ruzicka and Hugo (2018) to determine if there is evidence for shock metamorphism consistent with the previously inferred histories of their early impact excavation or lack thereof. We find that all samples have EBSD data consistent with a history of synmetamorphic impact shock (i.e., shock during thermal metamorphism), followed by postshock annealing. Petrographic analysis of Sena, Quenggouk, and Ste. Marguerite found exsolved Cu and irregular troilite within Fe metal, features consistent with shock metamorphism. All samples have a spatial variability in grain deformation consistent with shock processes, though Forest Vale, Quenggouk, and Ste. Marguerite may have relict signatures of accretional deformation as indicated by variability in their olivine deformation metrics. Within the context of previous workers’ geochemical observations, a more complex history is inferred for each sample. The “slow-cooled” samples, Quenggouk and Sena, were subject to synmetamorphic shock without excavation and annealed at depth. The same is true of the “fast-cooled” samples, Beaver Creek, Forest Vale, and Ste. Marguerite. However, after annealing, these rocks were excavated by a secondary impact or impacts around 5.2–6.5 Ma post-CAI formation and were left to cool rapidly on the surface of the H chondrite parent body. These interpreted histories are best compatible with a model of an impact-battered but intact onion shell for the earliest history of the H parent body. However, the EBSD evidence does not preclude a parent body disruption after 7 Ma post-CAI formation.