¹Christian Vollmer, ²Demie Kepaptsoglou, ³Jan Leitner, ⁴Henner Busemann, ⁴Nicole H. Spring, ²Quentin M. Ramasse, ³Peter Hoppe, ⁵Larry R. Nittler
¹Institut für Mineralogie, Universität Münster, D-48149 Münster, Germany;
²SuperSTEM Laboratory, Science & Technology Facilities Council Daresbury Laboratories, Daresbury WA4 4AD, United Kingdom;
³Abteilung Partikelchemie, Max-Planck-Institut für Chemie, D-55128 Mainz, Germany;
⁴School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL, United Kingdom; and
⁵Department of Terrestrial Magnetism, Carnegie Institution of Washington, NW, Washington, DC 20015

Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight 15N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C–O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C–O bonding environments and nanoglobular organics with dominant aromatic and C–N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid.

Reference
Vollmer C, Demie Kepaptsoglou D, Leitner J, Busemann H, Spring NH, Ramasse QM, Hoppe P, Nittler LR (2014)
Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites. Proceedings of the National Academy of Sciences 111, 43, 15338–15343
Link to Article [doi: 10.1073/pnas.1408206111]

¹Michael A. Velbel, ²Eric K. Tonui, ³Michael E. Zolensky
¹Department of Geological Sciences, 288 Farm Lane, 206 Natural Science Building, Michigan State University, East Lansing, Michigan 48824-1115
²Upstream Technology, BP America, Inc., Houston, TX 77079
³KT Astromaterials Research and Exploration Science, NASA Johnson Space Center, Houston, Texas 77058

Isovolumetric replacement of euhedral and anhedral olivine by serpentine produced both centripetal and meshwork textures in the CM2 chondrites ALH 81002 and Nogoya. The compositions of these textural varieties of serpentine are uniform within narrow limits within each previously studied meteorite, independent of the composition of olivine being replaced, and different between the two meteorites. In QUE 93005 (CM2), coarse olivines of widely varying compositions (Fo<76-99) are replaced in a texturally similar manner by compositionally uniform serpentine (Mg0.73±0.05Fe0.27±0.05)3Si2O5(OH)4. The narrow compositional range of serpentine replacing coarse olivine indicates that the aqueous solution from which the serpentine formed was compositionally uniform on scales at least as large as the meteorite (∼2.5 cm in longest dimension).Isovolumetric textures and compositional observations constrain elemental redistribution from coarse olivine to serpentine and to surrounding phases during serpentinization. Regardless of olivine’s composition, isovolumetric replacement of coarse olivines by serpentine of the observed composition released more Mg and Si from olivine than was required to form the serpentine. Excess Mg and Si released by olivine destruction and not retained in serpentine were exported from the replaced volume.Olivines with different Fa/Fo proportions contributed different amounts of Fe and Mg to the serpentine. Fayalitic olivines released more Fe than required to form the serpentines replacing them, so some of the Fe released from fayalitic olivine was exported from the replaced volumes. Forsteritic olivines released less Fe than required to form the serpentines replacing them, so some Fe was imported into the replaced volumes augmenting the small amount of Fe released from forsteritic olivine. In QUE 93005 Fo83.8 is the threshold composition between Fe-exporting and Fe-importing behavior in individual olivine-serpentine pairs, which released exactly the amount of Fe required to form serpentine of the observed uniform composition. Compositions of serpentines isovolumetrically replacing olivines, and threshold olivine compositions, in QUE 93005 differ from the corresponding values in Nogoya.Solvent and solute species diffused through the serpentine between the olivine-serpentine interface and the aqueous solution outside the isovolumetrically replaced volume. In QUE 93005, some of Fe released from fayalitic olivine in excess of the amount required to form serpentine reacted with S sourced from outside the pseudomorphs to form Fe-sulfide decorating the margins of the pseudomorphs of serpentine after fayalitic olivine. Such Fe-sulfide-decorated outlines after fayalitic olivine do not occur in ALH 81002 or Nogoya, indicating different Fe and S mass transfer regimes in different CM2 chondrites. Mg, Fe, Si, and S in the aqueous solution, including the excess Mg and Si exported from all serpentine pseudomorphs after olivine of any composition, were available to be incorporated into other phases spatially separate from the pseudomorphs after olivine, including regularly interstratified serpentine-tochilinite. Serpentines that replaced coarse olivines in QUE 93005 and ALH 81002 are less magnesian than those in Nogoya, indicating that the Nogoya aqueous-alteration environment was more evolved toward Mg-rich solutions. This easily located and characterized phase assemblage may be potentially useful for characterizing clasts of varying degrees of alteration in brecciated and heterogeneous CM chondrites, and future returned samples from mineralogically similar asteroids.

Reference
Velbel MA, Tonui EK, Zolensky ME (2014) Replacement of olivine by serpentine in the Queen Alexandra Range 93005 carbonaceous chondrite (CM2): Reactant-product compositional relations, and isovolumetric constraints on reaction stoichiometry and elemental mobility during aqueous Alteration. Geochimica et Cosmochimica Acta (in Press)
Link to Article [DOI: 10.1016/j.gca.2014.10.007]

Copyright Elsevier

¹Jennifer Hanley,²J. Brad Dalton III,³Vincent F. Chevrier,⁴Corey Jamieson,⁵R. Scott Barrows
¹Southwest Research Institute, Department of Space Studies, Boulder, CO, USA
²Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
³Arkansas Center for Space and Planetary Sciences, University of Arkansas, Fayetteville, AR, USA
⁴SETI Institute, Mountain View, CA, USA
⁵Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO, USA

Hydrated chlorine salts are expected to exist on a variety of planetary bodies, including inner planets such as Mars and outer planet satellites such as Europa. However, detection by remote sensing has been limited due to a lack of comparison data in spectral libraries. In addition, at low temperatures spectral features of many H2O-bearing species deviate from their room temperature behavior. Thus, we acquired spectra of NaCl, NaClO4∙nH2O, MgCl2∙nH2O, Mg(ClO4)2°6H2O, and Mg(ClO3)2°6H2O from 0.35-2.5 µm at both 298 and 80 K to observe the effects of temperature on diagnostic spectral features. In the NIR, the strongest spectral features often arise from water molecules. Increasing hydration states increases the depth and width of water bands. Interestingly, at low temperature these bands become narrower with sharper, better-defined minima, allowing individual bands to be more easily resolved. We also measured frozen eutectic solutions of NaCl, MgCl2, and KCl. We show that while care must be taken to acquire laboratory spectra of all hydrated phases at the relevant conditions (e.g. temperature, pressure) for the planetary body being studied, chlorine salts do possess distinct spectral features that should allow for their detection by remote sensing.

Reference
Hanley J, Brad Dalton III J, Chevrier VF, Jamieson C, Barrows RS (2014) Reflectance Spectra of Hydrated Chlorine Salts: The Effect of Temperature with Implications for Europa. Journal of Geophysical Research (in Press)
Link to Article [DOI: 10.1002/2013JE004565]

Published by arrangement with John Wiley & Sons

¹Bagnulo S, ²Cellino A,³Sterzik MF
¹Armagh Observatory, College Hill, Armagh BT61 9DG, UK
²INAF–Osservatorio Astrofisico di Torino, I-10025 Pino Torinese, Italy
³European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching, Germany

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

Reference
Bagnulo S, Cellino A,Sterzik MF (2014) Linear spectropolarimetry: a new diagnostic tool for the classification and characterization of asteroids. Monthly Notices of the Royal Astronomical Society (Letters) 446 (in Press)
Link top Article [doi: 10.1093/mnrasl/slu154 ]

¹Sami Mikhail, ^1,2Dimitri A. Sverjensky
¹Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015, USA
²Johns Hopkins University, Department of Earth and Planetary Sciences, Baltimore, Maryland 21218, USA

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

Reference
Mikhail S, Sverjensky DA (2014) Nitrogen speciation in upper mantle fluids and the origin of Earth’s nitrogen-rich atmosphere. Nature Geoscience (in Press)
Link to Article [doi:10.1038/ngeo2271]

¹Hutchinson IB, ¹Parnell J, ¹Edwards HGM, ¹Jehlicka J, ¹Marshall CP, ¹Harris LV, ¹Ingley R
¹Department of Physics and Astronomy, Space Research Centre, University of Leicester, University Road, Leicester LE1 7RH, UK
²Department of Geology and Petroleum Geology, University of Aberdeen, King׳s College, Aberdeen AB24 3UE, UK
³Centre for Astrobiology and Extremophiles Research, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK
⁴Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Sciences, Charles University, Albertov 6, 12843 Prague 2, Czech Republic
⁵Department of Geology, University of Kansas, 1475 Jayhawk Boulevard, Lawrence, KS 66045, USA

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Hutchinson IB, Parnell J, Edwards HGM, Jehlicka J, Marshall CP, Harris LV, Ingley R (2014) Potential for analysis of carbonaceous matter on Mars using Raman spectroscopy. Planetary and Space Science 103, 184–190

¹Megha Bhatt, ¹Urs Mall, ²Christian Wöhler, ²Arne Grumpe, ¹Roberto Bugiolacchi
¹Max-Planck-Institut für Sonnensystemforschung, Max-Planck-Straße 2, 37191 Katlenburg-Lindau, Germany
²Image Analysis Group, Dortmund University of Technology,Otto-Hahn Str.4,44227 Dortmund, Germany

The FeO weight percentage (wt.%) abundance of the Moon’s western nearside (View the MathML source55°S-55°N and View the MathML source5°E-40°W) is estimated using data from the InfraRed Spectrometer-2 (SIR-2) and the Moon Mineralogy Mapper (M3). In this study, we modified an FeO abundance estimation algorithm (Bhatt et al., 2012) which relies exclusively on the 2-μm absorption band parameters. The modified FeO abundance estimation algorithm and the regression-based elemental abundance estimation algorithm (Wöhler et al., 2014) which is based on the 1-μm and 2-μm absorption band parameters is applied to the M3 data. We have compared results obtained from these two modified algorithms with a previously published Clementine’s FeO wt.% map (Lucey et al., 2000). The effects of topography and space weathering on FeO wt.% estimates have been successfully minimized using the modified algorithm based on the 2-μm absorption band parameters. Thus, this algorithm can be successfully applied at middle to high latitudes. Furthermore, a correction for TiO2 is applied to the FeO abundance estimation algorithm based on the 2-μm absorption band parameters using the M3 data. Our comparative study shows a good correspondence between the three algorithms discussed. There are two locations: the crater Tycho and the region around Rima Bode which show major discrepancies. Our modified algorithm based on the 2-μm absorption parameters predicts 3-4 wt.% less FeO for the ray system of Tycho than for the surrounding region. The average iron abundance for the lunar highlands is about 6 wt.% and for the mare regions is about 16 wt.% using the regression-based elemental abundance estimation algorithm and the algorithm based on the 2-μm absorption parameters. This result is consistent with the previous analysis using Lunar Prospector Gamma-Ray Spectrometer data sets. The FeO wt.% is in the range 20-24 wt.% for the high-Ti basalts using both the modified iron abundance estimation and the regression-based elemental abundance estimation algorithms.

Reference
Bhatt M, Mall U, Wöhler C, Grumpe A, Bugiolacchi R (2014) A Comparative study of iron abundance estimation methods: application to the western nearside of the moon. Icarus (in Press)
Link to Article [DOI: 10.1016/j.icarus.2014.10.023]

Copyright Elsevier

¹Amy Bonsor, ¹Zoë M. Leinhardt, ¹Philip J. Carter, ²Tim Elliott, ²Michael J. Walter, ³Sarah T. Stewart
¹School of Physics, H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
²School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, UK
³Department of Earth and Planetary Sciences, University of California, Davis, One Shields Avenue, Davis, California 95616, USA

Several lines of evidence indicate a non-chondritic composition for Bulk Earth. If Earth formed from the accretion of chondritic material, its non-chondritic composition, in particular the super-chondritic 142Nd/144Nd142Nd/144Nd and low Mg/Fe ratios, might be explained by the collisional erosion of differentiated planetesimals during its formation. In this work we use an N-body code, that includes a state-of-the-art collision model, to follow the formation of protoplanets, similar to proto-Earth, from differentiated planetesimals (> 100 km) up to isolation mass (> 0.16 M⊕). Collisions between differentiated bodies have the potential to change the core-mantle ratio of the accreted protoplanets. We show that sufficient mantle material can be stripped from the colliding bodies during runaway and oligarchic growth, such that the final protoplanets could have Mg/Fe and Si/Fe ratios similar to that of bulk Earth, but only if Earth is an extreme case and the core is assumed to contain 10% silicon by mass. This may indicate an important role for collisional differentiation during the giant impact phase if Earth formed from chondritic material.

Reference
Bonsor A, Leinhardt ZM, Carter PJ, Elliott T, Walter MJ, Stewart ST (2014) A collisional origin to earth’s non-chondritic composition? Icarus (in Press)
Link to Article [DOI: 10.1016/j.icarus.2014.10.019]

Copyright Elsevier

¹Allan H. Treiman, ²Justin Filiberto
¹Lunar and Planetary Institute, Houston, Texas, USA
²Department of Geology, Southern Illinois University, Carbondale, Illinois, USA

The chemical compositions of shergottite meteorites, basaltic rocks from Mars, provide a broad view of the origins and differentiation of these Martian magmas. The shergottite basalts are subdivided based on their Al contents: high-Al basalts (Al > 5% wt) are distinct from low-Al basalts and olivine-phyric basalts (both with Al < 4.5% wt). Abundance ratios of highly incompatible elements (e.g., Th, La) are comparable in all the shergottites. Abundances of less incompatible elements (e.g., Ti, Lu, Hf) in olivine-phyric and low-Al basalts correlate well with each other, but the element abundance ratios are not constant; this suggests mixing between components, both depleted and enriched. High-Al shergottites deviate from these trends consistent with silicate mineral fractionation. The “depleted” component is similar to the Yamato-980459 magma; approximately, 67% crystal fractionation of this magma would yield a melt with trace element abundances like QUE 94201. The “enriched” component is like the parent magma for NWA 1068; approximately, 30% crystal fractionation from it would yield a melt with trace element abundances like the Los Angeles shergottite. This component mixing is consistent with radiogenic isotope and oxygen fugacity data. These mixing relations are consistent with the compositions of many of the Gusev crater basalts analyzed on Mars by the Spirit rover (although with only a few elements to compare). Other Mars basalts fall off the mixing relations (e.g., Wishstone at Gusev, Gale crater rocks). Their compositions imply that basalt source areas in Mars include significant complexities that are not present in the source areas for the shergottite basalts.

Reference
Treiman AH, Filiberto J (2014) Geochemical diversity of shergottite basalts: Mixing and fractionation, and their relation to Mars surface basalts. Meteoritics&Planetary Science (in Press)
Link to Article [DOI: 10.1111/maps.12363]

Published by arrangement with John Wiley and Sons

¹Xie, X., ^“Chen, M., ³Zhai, S., ¹Wang, F.
¹Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
²State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
³Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, School of Earth and Space Sciences, Peking University, Beijing, China

An assemblage with FeNi metal, troilite, Fe-Mn-Na phosphate, and Al-free chromite was identified in the metal-troilite eutectic nodules in the shock-produced chondritic melt of the Yanzhuang H6 meteorite. Electron microprobe and Raman spectroscopic analyses show that a few phosphate globules have the composition of Na-bearing graftonite (Fe,Mn,Na)3(PO4)2, whereas most others correspond to Mn-bearing galileiite Na(Fe,Mn)4(PO4)3 and a possible new phosphate phase of Na2(Fe,Mn)17(PO4)12 composition. The Yanzhuang meteorite was shocked to a peak pressure of 50 GPa and a peak temperature of approximately 2000 °C. All minerals were melted after pressure release to form a chondritic melt due to very high postshock heat that brought the chondrite material above its liquidus. The volatile elements P and Na released from whitlockite and plagioclase along with elements Cr and Mn released from chromite are concentrated into the shock-produced Fe-Ni-S-O melt at high temperatures. During cooling, microcrystalline olivine and pyroxene first crystallized from the chondritic melt, metal-troilite eutectic intergrowths, and silicate melt glass finally solidified at about 950–1000 °C. On the other hand, P, Mn, and Na in the Fe-Ni-S-O melt combined with Fe and crystallized as Fe-Mn-Na phosphates within troilite, while Cr combined with Fe and crystallized as Al-free chromite also within troilite.

Reference
Xie X, Chen M, Zhai S, Wang, F (2014) Eutectic metal + troilite + Fe-Mn-Na phosphate + Al-free chromite assemblage in shock-produced chondritic melt of the Yanzhuang chondrite. Meteoritics & Planetary Science (in Press)
Link to Article [doi: 10.1111/maps.12379]

Published by arrangement with John Wiley & Sons