Probing molecular and isotopic features of meteoritic insoluble organic matter by solid‐state nuclear magnetic resonance spectroscopy with sub‐milligram sample

1M. K. Pandey, 2,3Y. Nishiyama, 4,5,6P. Tekely
Meteoritics & Planetary Science (in Press) Link to Article []
1Indian Institute of Technology Ropar, Rupnagar, Punjab, India
2RIKEN CLST‐JEOL Collaboration Center, Yokohama, Kanagawa, Japan
3JEOL Resonance Inc., Akishima, Tokyo, Japan
4École Normale Supérieure, Paris, France
5Sorbonne Université, Paris, France
6CNRS, UMR 7203 Laboratoire des Biomolécules, Paris, France
Published by arrangement with John Wiley & Sons

We recorded one‐ and two‐dimensional solid‐state nuclear magnetic resonance spectra of meteoric insoluble organic matter with unprecedented sensitivity and resolution permitting us to reveal unambiguous spectroscopic fingerprints relevant to its molecular and isotopic features. Two‐dimensional 1H‐1H and 1H‐13C correlation experiments have unveiled the spatial proximity between aliphatic and aromatic groups proving a highly branched character of a rigid macromolecular network composed of short aliphatic chains linking together small aromatic units. One‐dimensional 2H and two‐dimensional 1H‐2H correlation spectroscopy delivered evidence of significant reduction in the deuterium enrichment of aromatic species relevant to interstellar processes, proto‐planetary disk chemistry, and to determining the origin of the meteoritic insoluble organic matter. The experimental approach developed in this work opens new perspectives for systematic and nondestructive analysis at the molecular level of meteoritic insoluble organic matter even with a very small amount of sample from some particularly rare chondrites.

Solid-solid hydration and dehydration of Mars-relevant chlorine salts: Implications for Gale Crater and RSL locations

1R.V.Gough, 2K.M.Primm, 3E.G.Rivera-Valentín, 4G.M.Martínez, 1M.A.Tolbert
Icarus (in Press) Link to Article []
1Department of Chemistry and Biochemistry and Cooperative Institute for Research in Environmental Sciences (CIRES), 216 UCB, University of Colorado, Boulder, CO 80309, USA
2Department of Space Studies, Southwest Research Institute, 1050 Walnut St. #300, Boulder, CO 80302, USA
3Lunar and Planetary Institute, Universities Space Research Association, Houston, TX 77058, USA
4Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI 48109, USA
Copyright Elsevier

Water vapor is likely being exchanged between the regolith and the atmosphere on Mars, according to evidence from multiple landing sites (including Gale Crater), satellite measurements and numerical modeling. The mechanism of this exchange is largely unknown but could involve the formation of water frost, the adsorption of thin films of water onto mineral surfaces, or the deliquescence or hydration of salts. Hydration, a solid-solid phase transition during which water molecules are incorporated into a crystal structure in stoichiometric amounts, is possible for many salts found at Gale Crater and elsewhere on Mars. These salts may therefore be acting as a source and sink for water vapor in the Martian regolith. Furthermore, salt hydration state may be used as a marker for the presence of liquid water on present-day Mars. For example, the hydrated, crystalline perchlorate and chloride salts detected at recurring slope lineae (RSL) locations have been proposed to form from liquid brines rather than by experiencing hydration by atmospheric water vapor. Here we use an environmental cell coupled to a Raman microscope to experimentally study the hydration and dehydration of magnesium chloride (MgCl2), calcium perchlorate (Ca(ClO4)2), and calcium chloride (CaCl2) with the goal of determining which of these salts are capable of experiencing hydration on diurnal time scales. Other potential hydration phase transitions of chlorine-containing salts are thought to be less likely. Specifically, we study the transition between magnesium chloride tetrahydrate and hexahydrate, anhydrous calcium perchlorate and hydrated calcium perchlorate, and calcium chloride dihydrate and hexahydrate. We find that under conditions measured by the REMS instrument at Gale Crater, some chlorine-containing salts can readily hydrate and other salts can readily dehydrate, but no salt system studied here is likely to undergo both processes at the surface on diurnal time scales. With respect to RSL formation, these experiments suggest that atmospheric hydration of these salt systems may be too slow or otherwise not feasible. Hence, hydrated salts formed recently at active RSL locations on Mars may indeed be an indicator of the presence of liquid water.

Mapping olivine abundance on asteroid (25143) Itokawa from Hayabusa/NIRS data

1,4L.Nardi, 1,2E.Palomba, 1,3A.Longobardo, 1,5A.Galiano, 1F.Dirri
Icarus (in Press) Link to Article []
1INAF-IAPS, Via Fosso del Cavaliere 100, Roma 00133, Italy
2ASI-SSDC, via del Politecnico, Roma 00133, Italy
3Università Parthenope, Dist. Centro Direzionale Isola C4, 80143, Italy
4La Sapienza Università di Roma, Piazzale Aldo Moro 5, Roma 00185, Italy
5Università degli Studi di Roma Tor Vergata, Via Orazio Raimondo 18, Roma 00173, Italy
Copyright Elsevier 

Olivine is one of the main abundant mineral in the Solar System, and the determination of its abundance on a surface may give fundamental information about its evolution. The study of surface distribution of olivine on asteroid (25143) Itokawa through near-Infrared reflectance spectroscopy is a difficult goal because olivine and pyroxene bands centred at 1 μm and 2 μm are not entirely included in Hayabusa/NIRS’ spectral range. In this work, the retrieval of olivine abundance has been performed by applying two different methods: the first one uses some spectral indices to retrieve olivine abundance, whilst the second one consists of the application of the Hapke’s theory in order to create synthetic spectra aimed at fitting a selection of NIRS’ spectra. The analysis performed with the first method brought to an approximately homogeneous distribution of olivine content (60  ±  15% on average) on Itokawa’s surface, with the exception of Sagamihara region, which has a slightly (up to 10%) lower olivine content. The second method brought to an average 60  ±  7.5% olivine content within 5 selected spectra, with the same reduction found in the spectrum from the Sagamihara region. All these values are in agreement with literature values on this topic, especially with the ones retrieved from particles sampled in Muses Sea by the Hayabusa probe.

Feedstocks of the Terrestrial Planets

Richard W. Carlson1, Ramon Brasser2, Qing-Zhu Yin3, Mario Fischer-Gödde4, Liping Qin5
Space Science Reviews 2018 214:121 Link to Article [DOI: 10.1007/s11214-018-0554-x]
1Department of Terrestrial MagnetismCarnegie Institution for ScienceWashingtonUSA
2Earth Life Science InstituteTokyo Institute of TechnologyTokyoJapan
3Department of Earth and Planetary SciencesUniversity of California, DavisDavisUSA
4Institut für Geologie und MineralogieUniversity of CologneCologneGermany
5CAS Key Laboratory of Crust-Mantle Materials and EnvironmentUniversity of Science and Technology of ChinaHefeiChina

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Calibrating NIST SRM 683 as a new international reference standard for Zn isotopes

1,2Yang, Y., 2Zhang, X., 3Liu, S.-A., 4Zhou, T., 4Fan, H., 2Yu, H., 1,2Cheng, W., 2Huang, F.
Journal of Analytical Atomic Spectroscopy 33, 1777-1783 Link to Article [DOI: 10.1039/c8ja00249e]
1State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
2School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
3State Key Laboratory of Geological Process and Mineral Resources, China University of Geosciences, Beijing, 100083, China
4State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou 550081, China

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Morphology of sulfide minerals in some ordinary chondrites

1Hontsova, S.S., 2Danilenko, I.A., 2Yakovlev, G.A., 2Petrova, E.V., 1Maksimova, E.M., 1Nauhatsky, I.A.
AIP Conference Proceedings 2015, 020029 Link to Article [DOI: 10.1063/1.5055102]
1Department of Theoretical Physics and Solid State, Institute of Physical – Technical, Crimean Federal University, Simferopol, 295007, Russian Federation
2Department of Physical Techniques and Devices for Quality Control, Institute of Physics and Technology, Ural Federal University, Ekaterinburg, 620002, Russian Federation

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X-ray powder diffraction study of the stability of clathrate hydrates in the presence of salts with relevance to the Martian cryosphere

1,2Emmal Safi, 2Stephen P.Thompson, 1Aneurin Evans, 2Sarah J.Day, 2Claire A.Murray, 2Annabelle R.Baker, 1Joana M.Oliveira, 1Jacco Th.van Loon
Geochimica et Cosmochimica Acta (in Press) Link to Article []
1Astrophysics Group, Lennard-Jones Laboratories, Keele University, Keele, Staffordshire, ST5 5BG, UK
2Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
Copyright Elsevier

Water on the present day Martian surface is thought to exist in two thermally distinct sub-surface reservoirs: as ice in the cryosphere and as groundwater located deeper in the crust. These sub-surface environments are thought to contain saline, rather than pure, water and laboratory studies on whether or not clathrate hydrates can form in such environments are lacking. We fill this gap by performing synchrotron radiation X-ray powder diffraction to investigate the formation and evolution of clathrate hydrates in weak chloride solutions at CO2 pressures, and over temperature ranges, that are similar to those found in the Martian regolith. We have found that clathrate hydrates can form under conditions relevant to the Martian cryosphere, despite the presence of chloride salts. We find that the dissociation temperatures for CO2 clathrate hydrates formed in saline solutions are depressed by 10–20 K relative to those formed in pure water, depending on the nature of the salt and the CO2 pressure. We suggest that the inhibiting effect that salts such as MgCl2, CaCl2 and NaCl have on clathrate hydrate formation could also be related to the salts’ effect on the formation of the low temperature phase of ice. However, despite the inhibiting effect of the salts, we conclude that the presence of clathrate hydrates should still be possible under conditions likely to exist within the Martian cryosphere.