The interior and the fusion crust in Sariçiçek howardite: Study using X-ray diffraction, magnetization measurements and Mössbauer spectroscopy

1Maksimova, A.A.,2Unsalan, O.,1Chukin, A.V.,3Karabanalov, M.S.,4Jenniskens, P.,5Felner, I.,1Semionkin, V.A.,1Oshtrakh, M.I.
Spectrochimica Acta – Part A: Molecular abd Biomolecular Spectroscopy 228, 117819 Link to Article [DOI: 10.1016/j.saa.2019.117819]
1Institute of Physics and Technology, Ural Federal University, Ekaterinburg, 620002, Russian Federation
2Faculty of Science, Department of Physics, Ege University, Bornova, Izmir 35100, Turkey
3Institute of Material Science and Metallurgy, Ural Federal University, Ekaterinburg, 620002, Russian Federation
4SETI Institute, Mountain View, CA 94043, United States
5Racah Institute of Physics, The Hebrew University, Jerusalem, 91904, Israel

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Extraterrestrial amino acids and L‐enantiomeric excesses in the CM2 carbonaceous chondrites Aguas Zarcas and Murchison

1Daniel P. Glavin,1Jamie E. Elsila,1,2Hannah L. McLain,1,2José C. Aponte,1Eric T. Parker,1Jason P. Dworkin,4Dolores H. Hill,3,4Harold C. Connolly Jr.,4Dante S. Lauretta
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13451]
1NASA Goddard Space Flight Center, Greenbelt, Maryland, 20771 USA
Catholic University of America, Washington, District of Columbia, 20064 USA
2Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, 85721 USA
3Rowan University, Glassboro, New Jersey, 08028 USA
4Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, 85721 USA
Published by arrangement with John Wiley & Sons

The abundances, distributions, enantiomeric ratios, and carbon isotopic compositions of amino acids in two fragments of the Aguas Zarcas CM2 type carbonaceous chondrite fall and a fragment of the CM2 Murchison meteorite were determined via liquid chromatography time‐of‐flight mass spectrometry and gas chromatography isotope ratio mass spectrometry. A suite of two‐ to six‐carbon aliphatic primary amino acids was identified in the Aguas Zarcas and Murchison meteorites with abundances ranging from ~0.1 to 158 nmol/g. The high relative abundances of α‐amino acids found in these meteorites are consistent with a Strecker‐cyanohydrin synthesis on these meteorite parent bodies. Amino acid enantiomeric and carbon isotopic measurements in both fragments of the Aguas Zarcas meteorites indicate that both samples experienced some terrestrial protein amino acid contamination after their fall to Earth. In contrast, similar measurements of alanine in Murchison revealed that this common protein amino acid was both racemic (D ≈ L) and heavily enriched in 13C, indicating no measurable terrestrial alanine contamination of this meteorite. Carbon isotope measurements of two rare non‐proteinogenic amino acids in the Aguas Zarcas and Murchison meteorites, α‐aminoisobutyric acid and D‐ and L‐isovaline, also fall well outside the typical terrestrial range, confirming they are extraterrestrial in origin. The detections of non‐terrestrial L‐isovaline excesses of ~10–15% in both the Aguas Zarcas and Murchison meteorites, and non‐terrestrial L‐glutamic acid excesses in Murchison of ~16–40% are consistent with preferential enrichment of circularly polarized light generated L‐amino acid excesses of conglomerate enantiopure crystals during parent body aqueous alteration and provide evidence of an early solar system formation bias toward L‐amino acids prior to the origin of life.

A thick crustal block revealed by reconstructions of early Mars highlands

1,2Sylvain Bouley,3James Tuttle Keane,4David Baratoux,5Benoit Langlais,6Isamu Matsuyama,1Francois Costard,7Roger Hewins,8Valerie Payré,7Violaine Sautter,1Antoine Séjourné,4Olivier Vanderhaeghe,2Brigitte Zanda

Nature Geoscience 13, 105-109 Link to Article [DOIhttps://doi.org/10.1038/s41561-019-0512-6]

1GEOPS – Géosciences Paris Sud, Univ. Paris-Sud, CNRS, Université Paris-Saclay, Orsay, France
2IMCCE – Observatoire de Paris, CNRS-UMR 8028, Paris, France
3California Institute of Technology, Pasadena, CA, USA
4Geosciences Environnement Toulouse, UMR 5563 CNRS, IRD & Université de Toulouse, Toulouse, France
5Laboratoire de Planétologie et Géodynamique, CNRS UMR 6112, Université de Nantes, Université d’Angers, Nantes, France
6Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
7Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie (IMPMC) – Sorbonne Université- Muséum National d’Histoire Naturelle, UPMC Université Paris 06, UMR CNRS 7590, IRD UMR 206, Paris, France
8Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, USA

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Volatiles in lunar felsite clasts: Impact-related delivery of hydrous material to an ancient dry lunar crust

1J.I.Simon,1,2R.Christoffersen,3J.Wang,1M.D.Mouser,4R.D.Mills,1,2,5D.K.Ross,2Z.Rahman,3C.M.O’D.Alexander
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2020.02.008]
1Center for Isotope Cosmochemistry and Geochronology, Astromaterials Research and Exploration Science, NASA Johnson Space Center, Houston, TX 77058, USA
2Jacobs, NASA Johnson Space Center, Mail Code XI3, Houston, TX 77058, USA
3Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015-1305, USA
4Department of Geological Sciences, University of North Carolina, Chapel Hill, NC 27599, USA
5University of Texas at El Paso/Jacobs-JETS, Houston, TX 77058, USA
Copyright Elsevier

In this detailed geochemical, petrological, and microstructural study of felsite clast materials contained in Apollo breccia samples 12013, 14321, and 15405, little evidence was found for relatively enriched reservoirs of endogenic lunar volatiles. NanoSIMS measurements have revealed very low volatile abundances (2 to 18 ppm hydrogen) in nominally anhydrous minerals (NAMS) plagioclase, potassic alkali feldspar, and SiO2 that make up a majority of these felsic lithologies. Yet these mineral assemblages and clast geochemistries on Earth would normally yield relatively high volatiles contents in their NAMS (∼20 to 80 ppm hydrogen). This difference is particularly notable in felsite 14321,1062 that exhibits extremely low volatile abundances (2 ppm hydrogen) and a relatively low amount of microstructural evidence for shock metamorphism given that it is a clast of the most evolved (∼74 wt. % SiO2) rock-type returned from the Moon. If taken at face value, ‘wet’ felsic magmas (∼1.2 to 1.7 wt. % water) are implied by the relatively high hydrogen contents of feldspar in felsite clasts in Apollo samples 12013 and 15405, but these results are likely misleading. These felsic clasts have microstructural features indicative of significantly higher shock stress than 14321,1062. These crustal lithologies likely obtained no more water from the lunar interior than the magma body producing 14321,1062. Rather, we suggest hydrogen was enriched in samples 12013 and 15405 by impact induced exchange, and/or partial assimilation of volatiles added to the surface of the Moon by a hydrated impactor (asteroid or comet) or the solar wind. Thus, the best estimate for magmatic water contents of felsic lunar magmas comes from 14321,1062 that leads to a calculated magmatic water content of 0.2 wt.%. This dry felsic magma has a slightly greater, but comparable water content to the ancient mafic magmas implied by the other lithologies that we have studied. Based on this and expanding evidence for a significantly dry ancient or early degassed Moon it is likely that some recent estimates (100’s ppm) of the water abundances in the lunar parental magma ocean have been overestimated.

Xenon Isotopes Identify Large-scale Nucleosynthetic Heterogeneities across the Solar System

1G. Avice,1M. Moreira,2J. D. Gilmour
The Astrophysical Journal 889, 68 Link to Article [DOI
https://doi.org/10.3847/1538-4357/ab5f0c]
1Unversité de Paris, Institut de physique du globe de Paris, CNRS, F-75005 Paris, France
2Department of Earth and Environmental Science, School of Natural Sciences, University of Manchester, Manchester, M13 9PL, UK

Nucleosynthetic isotopic anomalies in meteorites and planetary objects contribute to our understanding of the formation of the solar system. Isotope systematics of chondrites demonstrate the existence of a physical separation between isotopic reservoirs in the solar system. The isotopic composition of atmospheric xenon (Xe) indicates that its progenitor, U-Xe, is depleted in 134Xe and 136Xe isotopes relative to solar or chondritic end-members. This deficit supports the view that nucleosynthetic heterogeneities persisted during the solar system formation. Measurements of xenon emitted from comet 67P/Churyumov–Gerasimenko (67P) identified a similar, but more extreme, deficit of cometary gas in these isotopes relative to solar gas. Here we show that the data from 67P demonstrate that two distinct sources contributed xenon isotopes associated with the r-process to the solar system. The h-process contributed at least 29% (2σ) of solar system 136Xe. Mixtures of these r-process components and the s-process that match the heavy isotope signature of cometary Xe lead to depletions of the precursor of atmospheric Xe in p-only isotopes. Only the addition of pure p-process Xe to the isotopic mixture brings 124Xe/132Xe and 126Xe/132Xe ratios back to solar-like values. No pure p-process Xe has been detected in solar system material, and variation in p-process Xe isotopes is always correlated with variation in r-process Xe isotopes. In the solar system, p-process incorporation from the interstellar medium happened before incorporation of r-process nuclides or material in the outer edge of the solar system carries a different mixture of presolar sources as have been preserved in parent bodies.

 

Structural transformations and magnetic properties of plastically deformed FeNi-based alloys synthesized from meteoritic matter

1,2Kołodziej, M.,1Śniadecki, Z.,1Musiał, A.,3Pierunek, N.,4Ivanisenko, Y.,5Muszyński, A.,1Idzikowski, B.
Journal of Magnetism and Magnetic Materials 502, 166577 Link to Article [DOI: 10.1016/j.jmmm.2020.166577]
1Institute of Molecular Physics, Polish Academy of Sciences, Mariana Smoluchowskiego 17, Poznań, 60-179, Poland
2NanoBioMedical Centre, Adam Mickiewicz University in Poznań, Wszechnicy Piastowskiej 3, Poznań, 61-614, Poland
3Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, Poznań, 61-614, Poland
4Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, D-76344, Germany
5Institute of Geology, Adam Mickiewicz University, Bogumiła Krygowskiego 12, Poznań, 61-680, Poland

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Macro-classification of meteorites by portable energy dispersive X-ray fluorescence spectroscopy (pED-XRF), principal component analysis (PCA) and machine learning algorithms

1Allegretta, I.,2Marangoni, B.,3Manzari, P.,1Porfido, C.,1Terzano, R.,4De Pascale, O.,4 Senesi, G.S.
Talanta 212, 120785 Link to Article [DOI: 10.1016/j.talanta.2020.120785]
1Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari “Aldo Moro”, Via Amendola 165/A, Bari, 70126, Italy
2Physics Institute, Federal University of Mato Grosso do Sul, P.O. Box 549, Campo Grande, MS 79070-900, Brazil
3Agenzia Spaziale Italiana, via del Politecnico, Roma, 00133, Italy
4CNR – Istituto per la Scienza e Tecnologia dei Plasmi (ISTP) – Sede di Bari, Via Amendola 122/D, Bari, 70126, Italy

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