^1,2,3S.F.A. Batista, ^1,3T.M. Seixas, ^1,3M.A. Salgueiro da Silva, ^1,3R.M.G. de Albuquerque
¹Departamento de Física e Astronomia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto
²Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762, Porto
³Centro de Geofísica da Universidade de Coimbra, Av. Dr. Dias da Silva, 3000-134 Coimbra

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Reference
Batista SFA, Seixas TM, Salgueiro da Silva MA, de Albuquerque RMG (2014) Mineralogy of V-type asteroids as a constraining tool of their past history. Planetary&Space Science (in Press)
Link to Article [DOI: 10.1016/j.pss.2014.10.012]

^1,2F. Thiessen, ¹S. Besse, ³M.I. Staid, ⁴H. Hiesinger
¹European Space and Technology Centre, Noordwijk, Netherlands
²Leiden Observatory, Leiden University, Netherlands
³Planetary Science Institute, Tucson, Arizona, USA
⁴Institut für Planetologie, Westfälische Wilhelms-Universität Münster, Germany

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Reference
Thiessen F, Besse S, Staid MI, Hiesinger H (2014) Mapping lunar mare basalt units in mare Imbrium as observed with the moon mineralogy Mapper (M³). Planetary&Space Sciences (in Press)
Link to Article [DOI: 10.1016/j.pss.2014.10.003]

^1,2,3K.T. Howard,⁴C.M.O’D. Alexander, ⁵D.L. Schrader, ⁶K.A. Dyl

¹Kingsborough Community College of the City University of New York. 2001 Oriental Blvd. Brooklyn, NY 11235
²American Museum of Natural History
³The Natural History Museum, London
⁴Department of Terrestrial Magnetism, Carnegie Institution of Washington. 5241 Broad Branch Road, NW Washington, DC 20015-1305
⁵Smithsonian Institution, National Museum of Natural History, Washington. 10th & Constitution NW Washington, DC 20560-0119
⁶Department of Applied Geology, Curtin University of Technology, West Australia, Perth, WA 6845

The relative differences in the degrees of hydration should be reflected in any classification scheme for aqueously altered meteorites. Here we report the bulk mineralogies and degrees of hydration in 37 different carbonaceous chondrites: Renazzo-like (CR), Mighei-like (CM), and ungrouped (type 2) samples. This is achieved by quantifying the modal abundances of all major (phases present in abundances >1wt.%) minerals using Position Sensitive Detector X-ray Diffraction (PSD-XRD). From these modal abundances, a classification scheme is constructed that is based on the normalized fraction of phyllosilicate (View the MathML sourcetotalphyllosilicate/totalanhydroussilicate+totalphyllosilicate). Samples are linearly ranked from type 3.0 – corresponding to a phyllosilicate fraction of <0.05, to type 1.0 – corresponding to a total phyllosilicate fraction of >0.95. Powdered meteorite samples from any hydrated carbonaceous chondrite group can be ranked on this single classification scale. The resulting classifications for CRs exhibit a range from type 2.8 to 1.3, while for CMs the range is 1.7–1.2. The primary manifestation of aqueous alteration is the production of phyllosilicate, which ceased when the fluid supply was exhausted, leading to the preservation of anhydrous silicates in all samples. The variability in hydration indicates that either accretion of ices was heterogeneous or fluid was mobilized. From the bulk mineral abundances of the most hydrated samples, we infer that the initial mass fraction of H2O inside of their parent body(ies) asteroids was <20 wt.%. Bulk carbonaceous chondrite mineralogy evolved towards increasingly oxidizing assemblages as the extent of bulk hydration increased. This is consistent with the escape of reducing H₂ gas that is predicted to have been produced from water during hydration reactions.

Reference
Howard KT, Alexander CMOD, Schrader DL, Dyl KA (2014) Classification of hydrous meteorites (CR, CM and C2 ungrouped) by phyllosilicate fraction: PSD-XRD modal mineralogy and planetesimal Environments. Geochimica et Cosmochimica Acta (in Press) Link to Article [DOI: 10.1016/j.gca.2014.10.025] Copyright Elsevier

¹Ian B. Hutchinson, ¹Richard Ingley, ¹Howell G. M. Edwards, ¹Liam Harris, ¹Melissa McHugh, ^1,2Cedric Malherbe,³J. Parnell
¹Department of Physics and Astronomy, Space Research Centre, University of Leicester, Leicester LE1 7RH, UK
²Department of Inorganic Analytical Chemistry, Chemistry Institute (B6c), University of Liège, 4000 Liège, Belgium
³Department of Geology & Petroleum Geology, University of Aberdeen, King’s College, Aberdeen AB24 3UE, UK

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Reference
Hutchinson IB, Ingley R, Edwards HGM, Harris L, McHugh M, Malherbe C, Parnell J (2014) Research article: Raman spectroscopy on Mars: identification of geological and bio-geological signatures in Martian analogues using miniaturized Raman spectrometers. Philosophical Transactions Royal Society A., 372 20140204
Link to Article [doi:10.1098/rsta.2014.0204]

The most popular papers in October on Cosmochemistry Paper were:

1-Schmieder M, Schwarz WH, Trieloff M, Tohver E,Buchner E, Hopp J,Osinski GR (2014) New 40Ar/39Ar dating of the Clearwater Lake impact structures (Québec, Canada) – Not the binary asteroid impact it seems? Geochimica et Cosmoschimica Acta (in Press)
Link to Article [DOI: 10.1016/j.gca.2014.09.037]

2-Cartier C, Hammouda T, Boyet M, Bouhifd MA, DevidalJ-L (2014) Redox control of the fractionation of niobium and tantalum during planetary accretion and core formation. Nature Geoscience 7, 573–576
Link to Articel [doi:10.1038/ngeo2195

3-Schrader DL, Davidson J, Greenwood RC, Franchi IA, Gibson JM (2014) A water–ice rich minor body from the early Solar System: The CR chondrite parent Asteroid. Earth and Planetary Science Letters 407, 48-60
Link to Article [DOI: 10.1016/j.epsl.2014.09.030]

Cleeves LI, Bergin EA, Alexander CMOD, Du F, Graninger D, Öberg KI, Harries TJ (2014) The ancient heritage of water ice in the solar System. Science 345, 1590-1593
Link to Article [DOI: 10.1126/science.1258055]

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]

^1,2Janice L. Bishop, ³Peter A. J. Englert, ^1,4Shital Patel, ⁵Daniela Tirsch, ⁶Alex J. Roy, ^7,8Christian Koeberl,⁵Ute Böttger, ^5,9Franziska Hanke, ⁵Ralf Jaumann
¹Carl Sagan Center, SETI Institute, 189 Bernardo Avenue, Mountain View, CA, USA
²NASA Ames Research Center, Moffett Field, CA, USA
³Hawaii Institute of Geophysics and Planetology, University of Hawaii at Mânoa, HI, USA
⁴Department of Chemistry, San Jose State University, San Jose, CA, USA
⁵German Aerospace Center (DLR), Berlin, Germany
⁶Department of Land and Natural Resources, Honolulu, HI, USA
⁷Department of Lithospheric Research, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
⁸Natural History Museum, Burgring 7, 1010 Vienna, Austria
⁹Technische Universität Berlin, Berlin, Germany

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Reference
Bishop JL, Englert PAJ, Patel S, Tirsch D, Roy AJ, Koeberl C, Böttger U, Hanke F, Jaumann R (2014) Mineralogical analyses of surface sediments in the Antarctic Dry Valleys: coordinated analyses of Raman spectra, reflectance spectra and elemental abundances. Philosophical Transactions Royal Society A, 372, 2030
Link to Article [doi: 10.1098/rsta.2014.0198]

¹S.E.Braden,
¹J. D. Stopar,
¹M. S. Robinson,
¹S. J. Lawrence,
²C. H. van der Bogert
²H. Hiesinger
¹School of Earth and Space Exploration, Arizona State University, 1100 S. Cady Mall, Interdisciplinary A, Tempe, Arizona 85287-3603, USA
²Institut für Planetologie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany

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

Reference
Braden SE, Stopar JD, Robinson MS, Lawrence SJ, van der Bogert CH, Hiesinger H (2014) Evidence for basaltic volcanism on the Moon within the past 100 million years. Nature Geoscience 7, 787–791.
Link to Article [doi:10.1038/ngeo2252]

¹Peter H. Schultz, ¹Clara A. Eberhardy
¹Department of Earth, Environmental, and Planetary Sciences, 324 Brook Street, Brown University, Providence, RI 02912

High-speed spectra of hypervelocity impacts at the NASA Ames Vertical Gun Range (AVGR) captured the rapidly evolving conditions of impact-generated vapor as a function of impact angle, viewpoint, and time (within the first 50 μs). Impact speeds possible at the AVGR (< 7 km/s) are insufficient to induce significant vaporization in silicates, other than the high-temperature (but low-mass) jetting component created at first contact. Consequently, this study used powdered dolomite as a proxy for surveying the evolution and distribution of chemical constituents within much longer lasting vapor. Seven separate telescopes focused on different portions of the impact vapor plume and were connected through quartz fibers to two 0.35 cm monochromaters. Quarter-space experiments reduced the thermal background and opaque phases due to condensing particles and heated projectile fragments while different exposure times isolated components passing through different the fields of view, both above and below the surface within the growing transient cavity. At early times (< 5 μs), atomic emission lines dominate the spectra. At later times, molecular emission lines dominate the composition of the vapor plume times along a given direction. Layered targets and target mixtures isolated the source revealed that much of the vaporization comes from the uppermost surface. Collisions by projectile fragments downrange also make significant contributions for impacts below 60° (from the horizontal). Further, impacts into mixtures of silicates with powdered dolomite reveal that frictional heating must play a role in vapor production. Such results have implications for processes controlling vaporization on planetary surfaces including volatile release, atmospheric evolution (formation and erosion), vapor generated by the Deep Impact collision, and the possible consequences of the Chicxulub Impact.

Reference
Schultz PH, Eberhardy CA (2014) Spectral Probing of Impact-Generated Vapor in Laboratory Experiments. Icarus (in Press)
Link to Article [DOI: 10.1016/j.icarus.2014.10.041]

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