¹Patrick H. Donohue, ¹Clive R. Neal
¹Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA

Quantitative textural analysis is a powerful tool in the investigation of basalt crystallization. We present the first comprehensive crystal size distribution analysis of Apollo 17 high-titanium lunar basalts, with a focus on ilmenite. Crystal size distributions of ilmenite, pyroxene, plagioclase, olivine and armalcolite were determined for 18 high-Ti mare basalt samples from the Apollo 17 mission. A subset of the ilmenite size distribution (size bins of <0.6mm in length) reflects growth at post-eruption or post-emplacement cooling rates. Growth of these small ilmenite crystals is controlled by cooling rate and not bulk composition or ilmenite abundance. CSD characteristics tied to cooling rate determined by experiments yield estimates of cooling rate in natural samples. Matrix ilmenite grew at rates up to 250°C/hr, while most samples contained phenocrysts that originated in environments cooling at <3°C/hr. Textural characteristics of ilmenite phenocrysts are used to develop a relative stratigraphy for the samples within a lava flow based upon comparisons with terrestrial analogues.

Reference
Donohue PH, Neal CR (2014) Quantitative textural analysis of ilmenite in Apollo 17 high-titanium mare basalts. Geochimica et Cosmochimica Acta (in Press)
Link to Article [DOI: 10.1016/j.gca.2014.11.002]

Copyright Elsevier

¹Kathleen E. Vander Kaaden, ¹Carl B. Agee, ¹Francis M. McCubbin
¹Institute of Meteoritics, Department of Earth & Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, USA

The density and compressibility of four synthetic molten lunar picritic glasses was investigated from 0-10 GPa and 1748-2473 K. The picritic glasses were collected from the lunar surface during the Apollo missions, and they are hypothesized to have rapidly quenched as glass beads during pyroclastic fire fountain eruptions. The specific melt compositions investigated in the present study are the Apollo 15 green glass Type C (A15C, TiO2 = 0.26 wt%), the Apollo 14 yellow glass (A14Y, TiO2 = 4.58 wt%), the Apollo 17 orange glass 74220-type (A17O TiO2 = 9.12 wt%), and the Apollo 14 black glass (A14B, TiO2 = 16.40 wt%). These glasses are reported to represent primary unfractionated melts, making them a prime candidate for experimental studies into lunar basalt density and compressibility during partial melting of the lunar mantle. Sink-float experiments were conducted on the synthetic molten lunar glass compositions using a piston-cylinder apparatus (P 2.5 GPa) in order to bracket the density of the melts. New sink-float data are reported for A15C, A14Y, and A17O, which are combined with previously published density and compressibility data on A15C, A17O, and A14B. Although the Ti-rich liquids are highly compressible at lower pressures, they become nearly incompressible at much higher pressures when compared to the molten low-Ti glasses. Consequently, the melts with the most TiO2 (A14B) are the least dense at higher pressures, a reversal of what is seen at lower pressures. This change in density and compressibility is attributed to changes in coordination of Ti and Fe in the silicate melt structure. As Ti4+ abundances in the silicate melt increase, predominantly [IV]Ti4+ and [IV]Fe2+ change to [VI]Ti4+ and [VI]Fe2+ in the melt structure. All of the data from the present study were used to calculate a Birch-Murnaghan equation-of-state (BM-EOS) for each melt composition. The BM-EOS model for each composition was then combined with previously published estimates for the residual mantle source mineralogy and depth of origin for each of the glasses to assess the density of the partial melt with respect to its point of origin. This information was used to determine whether or not the melt would rise or sink with respect to its source region. We determined that all melt compositions, with the exception of the A17O melt, should have been able to rise to the crust-mantle boundary as a result of buoyancy forces alone, although different mechanisms are likely required for magma ascent through the lunar crust. For the rise of A17O, other modes of ascent through the lunar mantle are required to extract this melt composition from the mantle, and volatiles are not a plausible solution on the grounds of melt density alone.

Reference
Vander Kaaden KE, Agee CB, McCubbin FM (2014) Density and compressibility of the molten lunar picritic glasses: Implications for the roles of Ti and Fe in the structures of silicate melts. Geochimica et Cosmochimica Acta (in Press)
Link to Article [DOI: 10.1016/j.gca.2014.10.029]

Copyright Elsevier

¹Yuka Fujii, ¹Jun Kimura, ²James Dohm, ³Makiko Ohtake
¹Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan.
²The University Museum, The University of Tokyo, Tokyo, Japan.
³Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Kanagawa, Japan.

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Reference
Fujii Y, Kimura J, Dohm J, Ohtake M (2014) Geology and Photometric Variation of Solar System Bodies with Minor Atmospheres: Implications for Solid Exoplanets. Astrobiology 14(9) 753-768.
Link to Article [doi:10.1089/ast.2014.1165]

¹Adam Culka, ¹Kateřina Osterrothová, ²Ian Hutchinson, ²Richard Ingley, ²Melissa McHugh, ³Aharon Oren, ⁴Howell G. M. Edward,¹Jan Jehlička
¹Institute of Geochemistry, Mineralogy, and Mineral Resources, Charles University in Prague, Prague, Czech Republic
²Department of Physics and Astronomy, University of Leicester, Leicester, UK
³Department of Plant and Environmental Sciences, The Alexander Silverman Institute of Life Sciences, The Edmond J. Safra Campus, Givat Ram, Jerusalem, Israel
⁴Division of Chemical and Forensic Sciences, University of Bradford, Bradford BD7 1DP, UK

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Reference
Culka A, Osterrothová K,Hutchinson I, Ingley R, McHugh M, Oren A, Edwards HGM, Jehlička J (2014) Research article: Detection of pigments of halophilic endoliths from gypsum: Raman portable instrument and European Space Agency’s prototype Analysis. Philosophical Transactions of the Royal Society A.,372 20140203
Link to Article [doi:10.1098/rsta.2014.0203]

^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]