M. Viikinkoski¹ et al. (>10)
¹Department of Mathematics, Tampere University of Technology, PO Box 553, 33101 Tampere, Finland

We use the recently released Atacama Large Millimeter Array (ALMA) and VLT/SPHERE science verification data, together with earlier adaptive-optics images, stellar occultation, and lightcurve data to model the 3D shape and spin of the large asteroid (3) Juno with the all-data asteroid modelling (ADAM) procedure. These data set limits on the plausible range of shape models, yielding reconstructions suggesting that, despite its large size, Juno has sizable unrounded features moulded by non-gravitational processes such as impacts.

Reference
Viikinkoski et al. (2015) VLT/SPHERE- and ALMA-based shape reconstruction of asteroid (3) Juno. Astronomy & Astrophysics 581, L3 (in Press)
Link to Article [ http://www.aanda.org/articles/aa/abs/2015/09/aa26626-15/aa26626-15.html]

T. Brachaniec, K. Szopa and Ł. Karwowski
Department of Geochemistry, Mineralogy and Petrology, Faculty of Earth Sciences, University of Silesia, Sosnowiec, Poland

Moldavites represent tektites derived from the Ries impact structure (~24 km diameter, ~15 Myr old) in southern Germany. Two new localities with parautochthonous moldavites in southwestern Poland were found. In these localities, fluvial sediments of the so-called Gozdnicka formation host the moldavites. Characteristic tektite features, especially bubbles and inclusions of lechatelierite, are reported. The moldavites’ size distribution and their abraded shapes indicate that they were redeposited from the nearby Lusatia substrewn field.

Reference
Brachaniec T, Szopa K and Karwowski Ł (2015) Two new discovery of parautochthonous moldavites in southwestern Poland, Central Europe. Meteoritics & Planetary Science (in Press)
Link to Article [ http://onlinelibrary.wiley.com/doi/10.1111/maps.12504/abstract]
Published by arrangement with John Wiley & Sons

S.M. Brown , T.L. Grove
Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139

We examine the fO₂-dependent melting conditions of the Apollo 14 yellow intermediate-Ti ultramafic glasses and the melting processes that formed the full suite of lunar yellow ultramafic glasses. Multiple saturation experiments indicate that the Apollo 14 yellow glass would have been in equilibrium with residual olivine and low-Ca pyroxene near 1530°C and 2.4 GPa at ΔIW = +2. At ΔIW = -2, the multiple saturation point moves to greater depth and higher temperature to 1580°C and 3.0 GPa. Combining the results of this study with that of [26] on more Ti-rich Apollo orange and red glass indicates that the fO2-induced change in multiple saturation pressure correlates with the Fe-Ti# (molar (FeO + TiO₂*)/(MgO + FeO + TiO₂*), where TiO₂* = all Ti calculated as Ti⁴⁺) of the liquid. Further, a decrease in the olivine Fe-Mg exchange coefficient at lower fO2 suggests that Fe²⁺ is complexing more efficiently with Ti³⁺ at the expense of Mg in the melt than it did with Ti⁴⁺ at higher fO₂.

Reference
Brown SM, Grove TL (2015) Origin of the Apollo 14, 15, and 17 yellow ultramafic glasses by mixing of deep cumulate remelts. Geochimica et Cosmochimica Acta (in Press)
Link to Article [ http://www.sciencedirect.com/science/article/pii/S0016703715005293]
Copyright Elsevier

¹Mattheus F.C. Verkaaik,^1,2 Jan-Hein Hooijschuur, ²Gareth R. Davies, ¹Freek Ariese
¹LaserLaB, Faculty of Sciences, VU University Amsterdam, Amsterdam, the Netherlands.
²Deep Earth and Planetary Science, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, the Netherlands.

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

Reference
Verkaaik MFC, Hooijschuur J-H, Davies GR, Ariese F (2015) Raman Spectroscopic Techniques for Planetary Exploration: Detecting Microorganisms through Minerals. Astrobiologie 15,8 697-707.
Link to Article [doi:10.1089/ast.2015.1329]

^1,2,3A.L. Fagan, ^1,2C.R. Neal
¹Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556
²NASA Lunar Science Institute
³Geosciences and Natural Resources Department, College of Arts and Sciences, 331 Stillwell Building, Western Carolina University, Cullowhee, NC 28723

This paper reports the detailed examination of three basalt clasts from Apollo 16 breccia 60639 that represent a new variant of high-Ti basalt returned from the Moon by the Apollo 16 mission. Mineral chemistry and whole-rock analyses were conducted on aliquots from three clasts (breccia matrix, basalt, and basalt + breccia matrix). The basalt clasts, which are not porphyritic, contain compositionally zoned pyroxene, olivine, and plagioclase crystals that represent the evolution of the magma during crystallization; ilmenite does not exhibit major-element compositional zoning within individual crystals. Mineral compositions are distinct between the basalt and breccia matrix lithologies. In addition, whole-rock analyses identify clear compositional differences between the basalt and breccia matrix lithologies in both major and trace element concentrations. The composition of the mixed lithology aliquots (i.e., basalt + breccia matrix) do not indicate simple two component mixing (i.e., compositions are not intermediate to the basalt and breccia end-members); this apparent incongruity can be accounted for by adding ∼19-40% plagioclase to an amalgamation of the average basalt and individual breccia clast compositions via impact mixing. Whole-rock analyses are consistent with previous studies, which suggested that a basalt clast from 60639 is chemically similar to Apollo 11 and 17 basalts. In particular, both major and trace elements suggest that the 60639 basalt clasts examined here have compositions that are distinct from Apollo 11 and 17 high-Ti basalts. Although the 60639 basalt clasts have similar characteristics to a variety of previously identified basalt types, the more extensive whole-rock analyses reported here indicate that they represent a type of Apollo high-Ti basalt heretofore unrecognized in the Apollo and lunar meteorite collections. By placing these new analyses in the context of other mare basalt compositions, a petrogenetic model for the basalts found in breccia 60639 is presented.

Reference
Fagan AL, Neal CR (2015) A New Lunar High-Ti Basalt Type Defined from Clasts in Apollo 16 Breccia 60639. Geochimica et Cosmochimica Acta (in Press)
Link to Article [doi:10.1016/j.gca.2015.08.007]
Copyright Elsevier

¹E. Cloutis, , ¹B. Berg, ¹P. Mann, ¹D. Applin
¹Department of Geography, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB, Canada R3B 2E9

We have measured reflectance spectra (0.35 to 20 μm) of a suite of minerals and synthetic compounds that contain low-Z (⩽ Na) elements as the major cation and/or the major anion in oxides/oxyhydroxides, and are relevant to planetary geology and astrobiology. The suite comprises Na-borates, Na-, K-, Ca-hydroxides, nitrates, nitrites, and peroxides. Na-borate spectra exhibit B-O fundamental vibrations between 7 and 14 μm, and overtones/combinations of these bands in the 1.55, 1.75, 2.15, and 2.25 μm regions. Na-, K-, and Ca-hydroxide reflectance spectra are characterized by OH and metal-OH fundamental vibrations near 3, 8, and 18 μm, and a number of overtone and combination absorption bands at shorter wavelengths, and a characteristic metal-OH band near 2.35 μm. The nitrate and nitrite spectra exhibit fundamental N-O vibrations in the 7-14 μm region and numerous combinations and overtones that are still detectable to as low as ∼1.8 μm. Na-peroxide is largely spectrally featureless below 24 μm, making its detection problematic, while H-peroxide has many OH-related absorption features below 2.5 μm that differ in position from those of H2O ice and liquid. The results of this study indicate that the borates, hydroxides, nitrates, nitrite, and hydrogen peroxide can all be uniquely identified using characteristic absorption features that are present below 2.5 μm. However, some of these features are weak, and their detectability will depend on the types and abundances of any accessory phases that may be present.

Reflectance
Cloutis E, Berg B, Mann P, Applin D (2015) Reflectance spectroscopy of low atomic weight and Na-rich minerals: Borates, hydroxides, nitrates, nitrites, and peroxide. Icarus (in Press)
Link to Article [doi:10.1016/j.icarus.2015.08.026]
Copyright Elsevier

¹D. J. Wilson, ¹B. T. Gänsicke, ²D. Koester, ¹O. Toloza, ¹A. F. Pala, ¹E. Breedt,³S. G. Parsons

¹Department of Physics, University of Warwick, Coventry CV4 7AL, UK
²Institut für Theoretische Physik und Astrophysik, University of Kiel, D-24098 Kiel, Germany
³Departamento de Física y Astronomía, Universidad de Valparaíso, Avenida Gran Bretaña 1111, Valparaíso 2360102, Chile

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

Reference
Wilson DJ, Gänsicke BT, Koester D, Toloza O, Pala AF, Breedt E, Parsons SG (2015)
The composition of a disrupted extrasolar planetesimal at SDSS J0845+2257 (Ton 345). Monthly Notices of the Royal Astronomical Society 451, 3237-3248.
Link to Article [doi: 10.1093/mnras/stv1201]

¹Aaron S. Bella, ¹Charles Shearera, ²J. Maarten deMoor, ¹Paula Provencio
¹Institute of Meteoritics and Department of Earth and Planetary Sciences, University of New Mexico
²OVSICORI, Universidad Nacional, Heredia, Costa Rica

In this work, we investigate the compositions and origin of metasomatic fluids responsible for the formation of sulfide replacement textures in Mg-Suite lithologies of lunar samples 67915-149 and 67915-150. We have constructed a quantitative thermodynamic model of the composition of the metasomatic fluid using fO2, fS2, and temperature constraints derived from a thermodynamic analysis of the metasomatic fluid-mineral reactions and the measured compositions of the phases in the sulfide assemblages. Results from this modeling indicate that the metasomatic fluid responsible for the formation of the sulfide replacement textures was likely dominated by a combination of H2 and CH4, with minor abundances of H2O, CO, and H2S. The modeling indicates that H2S was, by orders of magnitude, the dominant S-species present in the metasomatic fluid and S isotopes in the replacement sulfides suggest that the fluid experienced significant removal of H2S by sulfide precipitation. The calculated H2 and H2O contents of the metasomatic fluid are consistent with those that might be expected for the late stage degassing of shallowly emplaced, intrusive magma bodies.

Reference
Bell AS, Charles Shearera, deMoor JM, Provencio P (2015) Using the Sulfide Replacement Petrology in Lunar Breccia 67915 to Construct a Thermodynamic Model of S-bearing Fluid in the Lunar Crust. Geochimica et Cosmochimica Acta (in Press)
Link to Article [doi:10.1016/j.gca.2015.08.002]

Copyright Elsevier

The most popular papers on Cosmochemistry Papers in August were:

1-Holst JC, Paton C, Wielandt D., Bizzarro M. (2015) Tungsten isotopes in bulk meteorites and their inclusions—Implications for processing of presolar components in the solar protoplanetary disk. Meteoritics&Planetary Science (in Press) Link to Article [DOI: 10.1111/maps.12488]

2-Groopman E, Zinner E, Amari S, Gyngard F, Hoppe P, Jadhav M, Lin Y, Xu Y, Marhas K, Nittler LR (2015) Inferred Initial 26Al/27Al Ratios in Presolar Stardust Grains from Supernovae are Higher than Previously Estimated. Astrophyical Journal 803, 31. Link to Article [doi:10.1088/0004-637X/809/1/31]

3-Hoppe P, Leitner J, Kodolányi J (2015) New Constraints on the Abundances of Silicate and Oxide Stardust from Supernovae in the Acfer 094 Meteorite. Astrophysical Journal 808 L9. Link to Article [doi:10.1088/2041-8205/808/1/L9]

4-Lantz C, Brunetto R, Barucci MA, Dartois E, Duprat J, Engrand C, Godard M, Ledu D, Quirico E (2015) Ion irradiation of the Murchison meteorite: Visible to mid-infrared spectroscopic results. Astronomy & Astrophysics 577, A41 Link to Article [dx.doi.org/10.1051/0004-6361/201425398 ]

5-Chen H-W, Lee T, Lee D-C, Chen J-C (2015) Correlation of 48Ca, 50Ti, and 138La Heterogeneity in the Allende Refractory Inclusions. Astrophysical Journal 806 L21. Link to Article [doi:10.1088/2041-8205/806/1/L21]

^1,2Tomáš Magna, ¹Nikolaus Gussone, ^1,3Klaus Mezger
¹Institut für Mineralogie, Universität Münster, Corrensstr. 24, D-48149 Münster, Germany
²Czech Geological Survey, Klárov 3, CZ-118 21 Prague, Czech Republic
³Institut für Geologie, Universität Bern, Baltzerstr. 1+3, CH-3012 Bern, Switzerland

New Ca isotope data from a suite of Martian meteorites provide constraints on the Ca isotope composition of the Martian mantle and possible recycling of surface materials back into the mantle. A mean δ44/40Ca of 1.04±0.09‰1.04±0.09‰ (2SD) is estimated for the Martian mantle which can also be taken as an approximation for Bulk Silicate Mars. This value is identical with the estimates for Bulk Silicate Earth, and the inner Solar System planets can therefore be considered homogeneous with respect to Ca isotopes. The Ca isotope composition of two Martian dunites varies by ∼0.3‰∼0.3‰ despite strong chemical and mineralogical similarities and this difference can be caused by the presence of carbonate, probably of pre-terrestrial origin, implying a protracted period of the existence of CaCO3-rich fluids and sufficient amounts of CO2 on the surface of Mars. The variability of δ44/40Ca within the groups of shergottites and nakhlites (clinopyroxene cumulates) cannot be related to partial melting and fractional crystallization in any simple way. However, there is no necessity of incorporating surface lithologies with isotopically light Ca into the mantle sources of Martian meteorites. These inferences are consistent with the absence of large scale crust–mantle recycling and thus of plate tectonics on Mars.

Reference
Magna T, Gussone N, Mezger K (2015) The calcium isotope systematics of Mars. Earth and Planetary Science Letters 430, 86–94
Link to Article [doi:10.1016/j.epsl.2015.08.016]
Copyright Elsevier