¹I-Huan Chiu,²Kentaro Terada,³Takahito Osawa,⁴Changkun Park,⁵Soshi Takeshita,⁵Yasuhiro Miyake,¹Kazuhiko Ninomiya
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14059]
¹Institute Radiation Sciences, Osaka University, Osaka, Japan
²Graduate School of Science, Osaka University, Osaka, Japan
³Nuclear Science Research Institute, Japan Atomic Energy Agency, Ibaraki, Japan
⁴Korea Polar Research Institute, Incheon, Republic of Korea
⁵High Energy Accelerator Research Organization (KEK), Ibaraki, Japan
Published by arrangement with John Wiley & Sons

We report the result of a non-destructive elemental analysis of lunar meteorites using a negative muon beam at J-PARC. An experimental system of six Ge semiconductor detectors and a newly designed He analysis chamber (to enable quantitative analysis of Al) was used to provide a high signal-to-noise ratio for the detection of major elements from lunar rocks (Mg, Si, Fe, O, Ca, and Al). We performed a Monte Carlo simulation to determine the chemical compositions at two sides and the center of a sample (at depths of 0.33 and 0.96 mm below the sample surface, respectively) of the lunar meteorite DEW 12007. These results indicate that the three interior regions of DEW 12007 are likely to be 55.8:44.2, 51.4:48.6, and 54.4:45.6 wt% mixtures of anorthositic and basaltic clasts, respectively. This study is the first quantitative analysis of a heterogeneous meteorite interior using a negative muon beam. As elemental analysis using a muon beam is non-destructive and highly sensitive to light elements, including C, N, and O, the protocols established in this study are applicable to initial characterization of returned samples from the South Pole of the Moon.

¹Ali-Dib, Mohamad
Monthly Notices of the Royal Astronomical Society: Letters 520, L48 – L521 Open Access Link to Article [DOI 10.1093/mnrasl/slad002]
¹Center for Astro Particle and Planetary Physics (CAP3), New York University Abu Dhabi, PO Box, Abu Dhabi, 129188, United Arab Emirates

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¹Bonatti L.,¹Brugman B.L.,¹Subramani T.,²Leinenweber K.D.,¹Navrotsky A.
Review of Scientific Instruments 94, 054905 Link to Article [DOI 10.1063/5.0131946]
¹School of Molecular Sciences, Center for Materials of the Universe, Arizona State University, Tempe, 85287, AZ, United States
²Eyring Materials Center, Arizona State University, Tempe, 85287, AZ, United States

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¹Kremer, Christopher H.,¹Mustard, John. F.,¹Pieters, Carlé M.
Earth and Space Science 10, e2023EA002828 Open Access Link to Article [DOI 10.1029/2023EA002828]
¹Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, United States

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^1,2Lina Seybold,¹Claudia A. Trepmann,^1,2Stefan Hölzl,³Kilian Pollok,³Falko Langenhorst,¹Fabian Dellefant,^1,4Melanie Kaliwoda
Meteoritics & Planetary Science(in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14056]
¹Department of Earth and Environmental Sciences, Ludwig-Maximilians-University Munich, Munich, Germany
²Bavarian Natural History Collections, RiesKraterMuseum Nördlingen, Nördlingen, Germany
³Institute of Geoscience, Friedrich Schiller University Jena, Jena, Germany
⁴Mineralogical State Collection, Bavarian Natural History Collections, Munich, Germany
Published by arrangement with John Wiley & Sons

Shock-related calcite twins are characterized in calcite-bearing metagranite cataclasites within crystalline megablocks of the Ries impact structure, Germany, as well as in cores from the FBN1973 research drilling. The calcite likely originates from pre-impact veins within the Variscan metagranites and gneisses, while the cataclasis is due to the Miocene impact. Quartz in the metagranite components does not contain planar deformation features, indicating low shock pressures (<7 GPa). Calcite, however, shows a high density (>1/μm) of twins with widths <100 nm. Different types of twins (e-, f-, and r-twins) crosscutting each other can occur in one grain. Interaction of r- and f-twins results in a-type domains characterized by a misorientation relative to the host with a misorientation angle of 35°–40° and a misorientation axis parallel to an a-axis. Such a-type domains have not been recorded from deformed rocks in nature before. The high twin density and activation of different twin systems in one grain require high differential stresses (on the order of 1 GPa). Twinning of calcite at high differential stresses is consistent with deformation during impact cratering at relatively low shock pressure conditions. The twinned calcite microstructure can serve as a valuable low shock barometer.

¹Trygve Prestgard,¹Pierre Beck,¹Lydie Bonal,¹Jolantha Eschrig,²Jérôme Gattacceca,²Corinne Sonzogni,³Lisa Krämer Ruggiu
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14048]
¹Institut de Planétologie et d’Astrophysique de Grenoble, CNRS CNES, Université Grenoble Alpes, Grenoble, France
²CNRS, IRD, Coll France, INRA, CEREGE, Aix Marseille Univ, Aix-en-Provence, France
³Analytical-, Environmental- and Geo-Chemistry, Vrije Universiteit Brussel, Brussels, Belgium
Published by arrangement with John Wiley & Sons

Renazzo-type (CR) chondrites are a relatively rare group of carbonaceous chondrites with the vast majority having escaped thermal alteration. This means that CRs are composed of relatively unprocessed material, depending on the extent of aqueous alteration they have experienced. Hydration in CRs ranges from incipient alteration of matrix glass, up to nearly complete replacement of the rock by hydration products. The extent of secondary processes is often difficult to assess in these meteorites, due to their heterogeneity and diversity of alteration products. Yet, this is crucial in order to understand the extent of geological processing that occurred on the primary parent body. Additionally, the parent asteroids of CRs remain a mystery, mainly because terrestrial oxyhydroxide signatures dominate the reflectance spectra of CRs. In this work, we have conducted optical and IR reflectance and transmission spectra of 25 CR chondrites in order to (i) better evaluate the extent of aqueous alteration that occurred on the CR parent body, and (ii) find possible parent body candidates. Terrestrial oxyhydroxides were removed from 12 samples, as these tend to interfere with the optical-IR spectra of CRs. Our results suggest, among other, that (i) aqueous alteration in most of our CRs was limited to the matrix and (ii) most CRs may stem from a continuum of X-to-C complex asteroids, depending on their extent of aqueous alteration. More specifically, the endmembers being Xk/Xn types and Cgh/Ch types. This has strong implication in regard to what we can expect from the Psyche mission.