¹d’Ischia, M.,²Manini, P.,^3,4Moracci, M.,⁵Saladino, R.,^6,7Ball, V.,⁸Thissen, H.,⁸Evans, R.A.,⁹Puzzarini, C.,¹⁰Barone, V.
International Journal of Molecular Sciences 20 Link to Article [DOI: 10.3390/ijms20174079]
¹Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario di Monte S. Angelo ,Via Cupa Nuova Cinthia 21, Naples, 80126, Italy
²Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario di Monte S. Angelo ,Via Cupa Nuova Cinthia 21, Naples, 80126, Italy
³Department of Biology, University of Naples “Federico II”, Complesso Universitario di Monte S. Angelo ,Via Cupa Nuova Cinthia 21, Naples, 80126, Italy
⁴Institute of Biosciences and BioResources, National Research Council of Italy, Via P. Castellino 111, Naples, 80131, Italy
⁵Department of Ecological and Biological Sciences, University of Tuscia, Via S. Camillo de Lellis, Viterbo, 01100, Italy
⁶Institut National de la Santé et de la RechercheMédicale, 11 rue Humann, France
⁷Faculté de Chirurgie Dentaire, Université de Strasbourg, 1 Place de l’Hôpital, Strasbourg, 67000, France
⁸Commonwealth Scientific and Industrial Research Organisation (CSIRO) Manufacturing, Clayton, VIC 3168, Australia
⁹Department of Chemistry “Giacomo Ciamician”, University of Bologna, Via F. Selmi 2, Bologna, I-40126, Italy
¹⁰Scuola Normale Superiore, Piazza dei Cavalieri 7, Pisa, I-56126, Italy

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¹Christian VOLLMER,²Jan LEITNER,^3,4Demie KEPAPTSOGLOU,^3,5Quentin M. RAMASSE,⁶Henner BUSEMANN,¹Peter HOPPE
Meteoritics and Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13389]
¹Institut für Mineralogie, Westfalische Wilhelms-Universität, Corrensstr. 24, 48149 Münster, Germany
²Particle Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany
³SuperSTEM Laboratory, Keckwick Lane, Daresbury, UK
⁴Department of Physics, Jeol Nanocentre, University of York, Heslington YO 10 50D, UK
⁵School of Chemical and Process Engineering, Scbool of Physics, University of Leeds, Leeds LS2 9JT, UK
⁶Institut für Geochemie und Petrologie, ETH Zürich, Clausiusstr. 25, Zürich, Switzerland
Copyright Elsevier

Organic matter (OM) was widespread in the early solar nebula and might have played an important role for the delivery of prebiotic molecules to the early Earth. We investigated the textures, isotopic compositions, and functional chemistries of organic grains in the Renazzo carbonaceous chondrite by combined high spatial resolution techniques (electron microscopy–secondary ion mass spectrometry). Morphologies are complex on a submicrometer scale, and some organics exhibit a distinct texture with alternating layers of OM and minerals. These layered organics are also characterized by heterogeneous 15N isotopic abundances. Functional chemistry investigations of five focused ion beam‐extracted lamellae by electron energy loss spectroscopy reveal a chemical complexity on a nanometer scale. Grains show absorption at the C‐K edge at 285, 286.6, 287, and 288.6 eV due to polyaromatic hydrocarbons, different carbon‐oxygen, and aliphatic bonding environments with varying intensity. The nitrogen K‐edge functional chemistry of three grains is shown to be highly complex, and we see indications of amine (C‐NHx) or amide (CO‐NR2) chemistry as well as possible N‐heterocycles and nitro groups. We also performed low‐loss vibrational spectroscopy with high energy resolution and identified possible D‐ and G‐bands known from Raman spectroscopy and/or absorption from C=C and C‐O stretch modes known from infrared spectroscopy at around 0.17 and 0.2 eV energy loss. The observation of multiglobular layered organic aggregates, heterogeneous 15N‐anomalous compositions, and indication of NHx‐(amine) functional chemistry lends support to recent ideas that 15N‐enriched ammonia (NH3) was a powerful agent to synthesize more complex organics in aqueous asteroidal environments.

¹Quinn R.Shollenberger,¹Gregory A.Brennecka
Earth and Planetary Science Letters 529, 115866 Link to Article [https://doi.org/10.1016/j.epsl.2019.115866]
¹Institut für Planetologie, University of Münster, Wilhelm-Klemm-Straße 10, Münster, 48149, Germany
Copyright Elsevier

One way to study the original building blocks of the Solar System is to investigate primitive meteorites and their components. Specifically, isolating these meteorites’ individual components via sequential acid leaching can reveal isotopically diverse material present in the early Solar System, which can provide new insights into the mixing and transport processes that eventually led to planet formation. Such isotopic differences in the components are likely to be found in heavy rare earth elements, such as dysprosium (Dy), erbium (Er), and ytterbium (Yb), because their isotopes have different nucleosynthetic production pathways and the elements have significant differences in volatility; however, these specific elements have yet to be thoroughly investigated in the field of cosmochemistry. As such, we present the first combined Dy, Er, and Yb isotope compositions of sequential acid leachates from the Murchison meteorite, along with multiple bulk meteorites from different taxonomic classes. This work also presents a new method to separate, purify, and accurately measure Dy isotopes. Here we show that resolved Dy, Er, and Yb isotope variations in most bulk meteorites are due to neutron capture processes. However, Dy and Er isotopic compositions of bulk Murchison and Murchison leachates stem from the additions or depletions of a nucleosynthetic component formed by the s-process, most likely mainstream silicon carbide (SiC) grains. In contrast, the Yb isotope compositions of bulk Murchison and Murchison leachates display either unresolved or relatively small isotope anomalies. The disparate isotopic behavior between Dy-Er and Yb likely reflects their differing volatilities, with Dy and Er condensing/incorporating into the mainstream SiC grains, whereas the less refractory Yb remains in the gas phase during SiC formation. This work suggests that Yb is hosted in a non-SiC presolar carrier phase and, furthermore, that mainstream SiC grains may be the primary source of isotopic variation in bulk meteorites.

¹Max Gounelle, ²Matthieu Gounelle
Meteoritics & Planetary Science (in Press) Link to Article [doi: 10.1111/maps.13396]
¹Faculte de droit, Jean-Claude Escarras Centre for Comparative Law and Politics, UMR 7318 DICE, Universite de Toulon,
35 avenue Alphonse Daudet, 83056 Toulon Cedex, France
²Museum National d’Histoire Naturelle, Sorbonne Universites, CNRS, IMPMC – UMR CNRS 7590, 57 rue Cuvier,
75005 Paris, France
Published by Arrangement with John Wiley & Sons

Although meteorites are now considered as scientific objects, they still bear a
strong and powerful symbolic meaning due to their extraterrestrial provenance. The present article focuses on their legal status, in other words the collection of rules, very diverse in nature, which are applicable to them. Despite a growing international market, the Question of meteorites is often ignored or regarded as a detail in international relations and is rarely taken explicitly into account in negotiations and treaties. This relative neglect explains why
a non-State player, the Meteoritical Society, has taken methodological initiatives into meteoritic science and has effectively become a regulator of meteorite naming and acceptance, with a global scope. We show that to understand the legal status of meteorites, it is necessary to consider them under the prism of public international law, transnational law, and national law. We conclude that, despite the universality of meteorites as extraterrestrial objects, the variability of legal rules applicable to meteorites depending onto which territory they fall or where they are found. We note, however, that there is a trend toward regulatory uniformity in the scientific analysis of meteorites, which frames the practices of researchers and regulates traders’ activities. Finally, we contend that a Meteorite remains a badly defined legal object, because it can be viewed under many angles: as an object susceptible to private appropriation, as a “common thing” (res communis), or as an element of national heritage.

¹Lodders, K.
Springer Proceedings in Physics 219, 165-170 Link to Article [DOI: 10.1007/978-3-030-13876-9_27]
¹Dept. of Earth & Planetary Sciences and McDonnell Center for the Space Sciences, Washington University, Saint Louis, MO 63130, United States

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

¹Marina Martinez,¹Adrian J. Brearley,²Josep M. Trigo‐Rodríguez,¹Jordi Llorca
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13391]
¹Department of Earth & Planetary Sciences, MSC03-2040, University of New Mexico, Albuquerque, New Mexico 87131, USA
²Institute of Space Sciences (CSIC-IEEC), Campus UAB, Carrer de Can Magrans, s/n, 08193 Bellaterra (Barcelona),
Catalonia, Spain
³Institut de Tecniques Energetiques i Centre de Recerca en Nanoenginyeria, Universitat Politecnica de Catalunya, Diagonal 647,
ETSEIB, 08028 Barcelona, Catalonia, Spain
Published by arrangement with John Wiley & Sons

The petrology and mineralogy of shock melt veins in the L6 ordinary chondrite host of Villalbeto de la Peña, a highly shocked, L chondrite polymict breccia, have been investigated in detail using scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and electron probe microanalysis. Entrained olivine, enstatite, diopside, and plagioclase are transformed into ringwoodite, low‐Ca majorite, high‐Ca majorite, and an assemblage of jadeite‐lingunite, respectively, in several shock melt veins and pockets. We have focused on the shock behavior of diopside in a particularly large shock melt vein (10 mm long and up to 4 mm wide) in order to provide additional insights into its high‐pressure polymorphic phase transformation mechanisms. We report the first evidence of diopside undergoing shock‐induced melting, and the occurrence of natural Ca‐majorite formed by solid‐state transformation from diopside. Magnesiowüstite has also been found as veins injected into diopside in the form of nanocrystalline grains that crystallized from a melt and also occurs interstitially between majorite‐pyrope grains in the melt‐vein matrix. In addition, we have observed compositional zoning in majorite‐pyrope grains in the matrix of the shock‐melt vein, which has not been described previously in any shocked meteorite. Collectively, all these different lines of evidence are suggestive of a major shock event with high cooling rates. The minimum peak shock conditions are difficult to constrain, because of the uncertainties in applying experimentally determined high‐pressure phase equilibria to complex natural systems. However, our results suggest that conditions between 16 and 28 GPa and 2000–2200 °C were reached.

¹Chi Ma,²Oliver Tschauner,¹John R. Beckett,³Yang Liu,⁴Eran Greenberg,⁴Vitali B. Prakapenka
American Mineralogist 104,1521-1525 Link to Article [https://doi.org/10.2138/am-2019-6999]

¹Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, U.S.A.
²Department of Geoscience, University of Nevada, Las Vegas, Nevada 89154, U.S.A.
³Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, U.S.A.
⁴GSECARS, University of Chicago, Argonne National Laboratory, Chicago, Illinois 60637, U.S.A.
Copyright: The Mineralogical Society of America

Chenmingite (FeCr2O4; IMA 2017-036) is a high-pressure mineral, occurring as micrometer- to submicrometer-sized lamellae within precursor chromite grains along with xieite and Fe,Cr-rich ulvöspinel next to shock-induced melt pockets, from the Tissint martian meteorite. The composition of type chenmingite by electron probe analysis shows an empirical formula of (Fe2+0.75Mg0.23Mn0.02) (Cr1.60Al0.29Fe3+0.06Fe2+0.04Ti0.02)Σ2.01O4. The general and end-member formulas are (Fe,Mg)(Cr,Al)2O4 and FeCr2O4. Synchrotron X-ray diffraction reveals that chenmingite has an orthorhombic Pnma CaFe2O4-type (CF) structure with unit-cell dimensions: a = 9.715(6) Å, b = 2.87(1) Å, c = 9.49(7) Å, V = 264.6(4) Å3, and Z = 4. Both chenmingite and xieite formed by solid-state transformation of precursor chromite under high pressure and high temperature during the Tissint impact event on Mars. The xieite regions are always in contact with melt pockets, whereas chenmingite lamellae only occur within chromite, a few micrometers away from the melt pockets. This arrangement suggests that chenmingite formed under similar pressures as xieite but at lower temperatures, in agreement with experimental studies.

^1,2Aidan J.Ross,^1,2,3,4Hilary Downes,⁵Jason S.Herrin,⁶David W.Mittlefehldt,⁷Munir Humayun,²Caroline Smith
Geochemistry (Chemie der Erde) (In Press) Link to Article [https://doi.org/10.1016/j.chemer.2019.125539]
¹UCL/Birkbeck Centre for Planetary Sciences, University College London, Gower St, London, WC1E 6BT, UK
²Dept. of Earth Sciences, Natural History Museum, Cromwell Rd, London, SW7 5BD, UK
³Dept. of Earth and Planetary Sciences, Birkbeck University of London, Malet St., London, WC1E 7HX, UK
⁴Lunar and Planetary Institute/USRA, 3600 Bay Area Blvd, Houston, TX 77058, USA
⁵Earth Observatory of Singapore & Facility for Analysis, Characterisation, Testing, and Simulation, Nanyang Technological University, 639798, Singapore
⁶Astromaterials Research Office, NASA Johnson Space Center, 2101 NASA Parkway, Houston, TX 77058, USA
⁷Department of Earth, Ocean and Atmospheric, Science & National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Drive, Tallahassee, FL 32310, USA
Copyright Elsevier

Ureilite meteorites contain iron silicide minerals including suessite (Fe,Ni)₃Si, hapkeite (Fe₂Si) and xifengite (Fe₅Si₃). Despite occurring mostly in brecciated varieties presumed to be derived from the regolith of the ureilite parent asteroid, suessite has also been confirmed in one lithology of a dimict ureilite (NWA 1241). In contrast, Si-bearing Fe-metals occur in both brecciated and unbrecciated ureilites, implying that they were formed throughout the ureilite parent asteroid. We examined major, minor and trace element data of Fe-metals in seven brecciated ureilites (DaG 319, DaG 999, DaG 1000, DaG 1023, DaG 1047, EET 83309, and EET 87720) in addition to the dimict ureilite NWA 1241.

In this study we show that the silicides and Si-bearing metals in ureilites have similar siderophile trace element patterns; therefore, the precursors to the silicides were indigenous to the ureilite parent body. Si-free kamacite grains in brecciated ureilites show flatter, more chondritic siderophile element patterns. They may also be derived from the interior of the ureilite parent body, but some may be of exogenous origin (impactor debris), as are rare taenite grains.

On Earth, iron silicides are often formed under high-temperature and strongly reducing conditions (e.g. blast furnaces, lightning strikes). On the Moon, hapkeite (Fe₂Si) and other silicides have been found in the regolith where they were formed by impact-induced space weathering. In the Stardust aerogel, iron silicides derived from comet Wild2 were also formed by an impact-related reduction process. Silicides in ureilite regolith breccias may have formed by similar processes but ureilites additionally contain abundant elemental carbon which probably acted as a reducing agent, thus larger and more abundant silicide grains were formed than in the lunar regolith or cometary material. The origin of suessite in NWA 1241 may be analogous to that of reduced lithologies in the terrestrial mantle, although a regolith origin may also be possible since this sample is shown here to be a dimict breccia.

^1,2,3Jangmi Han,⁴Benjamin Jacobsen,⁵Ming-Chang Liu,¹Adrian J.Brearley,⁴Jennifer E.Matzel,³Lindsay P.Keller
Geochemistry (Chemie der Erde) (In Press) Link to Article [https://doi.org/10.1016/j.chemer.2019.125543]
¹Department of Earth and Planetary Sciences, MSC03-2040, University of New Mexico, Albuquerque, NM 87131, USA
²Lunar and Planetary Institute, USRA, 3600 Bay Area Boulevard, Houston, TX 77058, USA
³ARES, NASA Johnson Space Center, 2101 NASA Parkway, Houston, TX 77058, USA
⁴Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
⁵Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
Copyright Elsevier

A coordinated mineralogical and oxygen isotopic study of four fine-grained calcium-, aluminum-rich inclusions (CAIs) from the ALHA77307 CO3.0 carbonaceous chondrite was conducted. Three of the inclusions studied, 05, 1-65, and 2-119, all have nodular structures that represent three major groups, melilite-rich, spinel-rich, and hibonite-rich, based on their primary core mineral assemblages. A condensation origin was inferred for these CAIs. However, the difference in their primary core mineralogy reflects unique nebular environments in which multiple gas-solid reactions occurred under disequilibrium conditions to form hibonite, spinel, and melilite with minor perovskite and Al,Ti-rich diopside. A common occurrence of a diopside rim on the CAIs records a widespread event that marks the end of their condensation as a result of isolation from a nebular gas. An exception is a rare inclusion 2-112 that contains euhedral spinel crystals embedded in melilite, suggesting this CAI had been re-melted. All of the fine-grained CAIs analyzed in ALHA77307 are uniformly ¹⁶O-rich with an average Δ¹⁷O value of ∼−22 ± 5‰ (2σ), indicating no apparent correlation between their textures and oxygen isotopic compositions. We therefore conclude that a prevalent ¹⁶O-rich gas reservoir existed in a region of the solar nebula where CO3 fine-grained CAIs formed, initially by condensation and then later, some of them were reprocessed by melting event(s).

¹A.J.King,¹K.J.H.Phillips,²S.Strekopytov,¹C.Vita-Finzi,¹S.S.Russell
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2019.09.041]
¹Planetary Materials Group, Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, U.K
²Imaging and Analysis Centre, Natural History Museum, Cromwell Road, London SW7 5BD, U.K
Copyright Elsevier

The rare CI carbonaceous chondrites are the most aqueously altered and chemically primitive meteorites but due to their porous nature and high abundance of volatile elements are susceptible to terrestrial weathering. The Ivuna meteorite, type specimen for the CI chondrites, is the largest twentieth-century CI fall and probably the CI chondrite least affected by terrestrial alteration that is available for study. The main mass of Ivuna (BM2008 M1) has been stored in a nitrogen atmosphere at least since its arrival at the Natural History Museum (NHM), London, in 2008 (70 years after its fall) and could be considered the most pristine CI chondrite stone. We report the mineralogy, petrography and bulk elemental composition of BM2008 M1 and a second Ivuna stone (BM1996 M4) stored in air within wooden cabinets. We find that both Ivuna stones are breccias consisting of multiple rounded, phyllosilicate-rich clasts that formed through aqueous alteration followed by impact processing. A polished thin section of BM2008 M1 analysed immediately after preparation was found to contain sulphate-bearing veins that formed when primary sulphides reacted with oxygen and atmospheric water. A section of BM1996 M4 lacked veins but had sulphate grains on the surface that formed in ≤6 years, ∼3 times faster than previous reports for CI chondrite sections. Differences in the extent of terrestrial alteration recorded by BM2008 M1 and BM1996 M4 probably reflect variations in the post-recovery curation history of the stones prior to entering the NHM collection, and indicate that where possible pristine samples of hydrated carbonaceous should be kept out of the terrestrial environment in a stable environment to avoid modification. The bulk elemental composition of the two Ivuna stones show some variability due to their heterogeneous nature but in general are similar to previous analyses of CI chondrites. We combine our elemental abundances with literature values to calculate a new average composition for the Ivuna meteorite, which we find is in good agreement with existing compilations of element compositions in the CI chondrites and the most recent solar photospheric abundances.