B.A. Wing^a,b,c, J. Farquhar^c
aDepartment of Earth and Planetary Sciences, McGill University, Montreal QC H3A 2A7 CANADA
^bGEOTOP Research Center, C.P. 8888, Succursale Centre-ville, Montréal, QC H3C 3P8, CANADA
^cEarth System Science Interdisciplinary Center and Department of Geology, University of Maryland, College Park MD 20742 USA

We present a new set of high precision measurements of relative ³³S/³²S, ³⁴S/³²S, and ³⁶S/³²S values in lunar mare basalts. The measurements are referenced to the Vienna-Canyon Diablo Troilite (V-CDT) scale, on which the international reference material, IAEA-S-1, is characterized by δ³³S = -0.061 ‰, δ³⁴S ≡ -0.3 ‰ and δ36S = -1.27 ‰. The present dataset confirms that lunar mare basalts are characterized by a remarkable degree of sulfur isotopic homogeneity, with most new and published SF6-based sulfur isotope measurements consistent with a single mass-dependent mean isotopic composition of δ³⁴S = 0.58 ± 0.05 ‰, Δ³³S = 0.008 ± 0.006 ‰, and Δ³⁶S = 0.2 ± 0.2 ‰, relative to V-CDT, where the uncertainties are quoted as 99% confidence intervals on the mean. This homogeneity allows identification of a single sample (12022, 281) with an apparent ³³S enrichment, possibly reflecting cosmic-ray-induced spallation reactions. It also reveals that some mare basalts have slightly lower δ³⁴S values than the population mean, which is consistent with sulfur loss from a reduced basaltic melt prior to eruption at the lunar surface. Both the sulfur isotope homogeneity of the lunar mare basalts and the predicted sensitivity of sulfur isotopes to vaporization-driven fractionation suggest that less than ≈1-10% of lunar sulfur was lost after a potential moon-forming impact event.

Reference
Wing BA, Farquhar J (2015) Sulfur isotope homogeneity of lunar mare basalts. Geochimica et Cosmochimica Acta (in Press)
Link to Article [ http://www.sciencedirect.com/science/article/pii/S0016703715005323]
Copyright Elsevier

J.C. Aponte^1,2, J.P. Dworkin¹ and J.E. Elsila^1
1Solar System Exploration Division, Code 691, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
²Department of Chemistry, Catholic University of America, Washington, District of Columbia, USA

The CI1 Orgueil meteorite is a highly aqueously altered carbonaceous chondrite. It has been extensively studied, and despite its extensive degree of aqueous alteration and some documented instances of contamination, several indigenous organic compounds including amino acids, carboxylic acids, and nucleobases have been detected in its carbon-rich matrix. We recently developed a novel gas chromatographic method for the enantiomeric and compound-specific isotopic analyses of meteoritic aliphatic monoamines in extracts and have now applied this method to investigate the monoamine content in Orgueil. We detected 12 amines in Orgueil, with concentrations ranging from 1.1 to 332 nmol g^-1 of meteorite and compared this amine content in Orgueil with that of the CM2 Murchison meteorite, which experienced less parent-body aqueous alteration. Methylamine is four times more abundant in Orgueil than in Murchison. As with other species, the amine content in Orgueil extracts shows less structural diversity than that in Murchison extracts. We measured the compound-specific stable carbon isotopic ratios (δ¹³C) for 5 of the 12 monoamines detected in Orgueil and found a range of δ¹³C values from –20 to +59‰. These δ¹³C values fall into the range of other meteoritic organic compounds, although they are ¹³C-depleted relative to their counterparts extracted from the Murchison meteorite. In addition, we measured the enantiomeric composition for the chiral monoamines (R)- and (S)-sec-butylamine in Orgueil, and found it was racemic within experimental error, in contrast with the l-enantiomeric excess found for its amino acid structural analog isovaline. The racemic nature of sec-butylamine in Orgueil was comparable to that previously observed in Murchison, and to other CM2 and CR2 carbonaceous chondrites measured in this work (ALH 83100 [CM1/2], LON 94101 [CM2], LEW 90500 [CM2], LAP 02342 [CR2], and GRA 95229 [CR2]). These results allow us to place some constraints on the effects of aqueous alteration observed over the monoamine concentrations in Orgueil and Murchison, and to evaluate the primordial synthetic relationships between meteoritic monoamines and amino acids.

Reference
Aconite JC, Dworkin JP and Elsila JE (2015) Indigenous aliphatic amines in the aqueously altered Orgueil meteorite. Meteoritics & Planetary Science (in Press)
Link to Article [http://onlinelibrary.wiley.com/doi/10.1111/maps.12507/abstract]
Published by arrangement with John Wiley & Sons

M. E. Sanborn^a, R. W. Carlson^b, M. Wadhwa^a
aCenter for Meteorite Studies, School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ, 85287-1404, USA
^bDepartment of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Rd. NW, Washington, DC 20015-1305, USA

Angrites are a group of basaltic achondrites with distinctive mineralogic and geochemical characteristics that have the potential to provide insights into processes occurring on planetesimals in the early Solar System. These achondrites have been used as anchors linking the relative age information obtained from short-lived, extinct chronometers (e.g., Al-Mg, Hf-W, and Mn-Cr) with absolute chronometers (e.g., U-Pb). Angrites provide excellent examples of early differentiation processes, such as core formation and silicate differentiation, on protoplanetary bodies. The significant increase in the number of known angrite samples in recent years has offered the opportunity to compare several short- and long-lived isotopic systems in samples with different petrogenetic histories that formed on the same parent body. To this end, the ¹⁴⁷Sm-¹⁴³Nd, ¹⁴⁶Sm-¹⁴²Nd, ¹⁷⁶Lu-¹⁷⁶Hf, and ⁸⁷Rb-⁸⁶Sr isotope systematics have been investigated in a suite of plutonic, coarse-grained (NWA 4590, NWA 4801, and NWA 2999) and quenched, fine-grained (D’Orbigny) angrites. The coupled ¹⁴⁷,¹⁴⁶Sm-¹⁴³,¹⁴²Nd systematics indicate possible isotopic disturbances in two angrites (D’Orbigny and NWA 2999) resulting from post-crystallization processes. The internal ¹⁴⁶Sm-¹⁴²Nd isochrons of two coarse-grained angrites (NWA 4590 and NWA 4801) provide an updated best estimate of the initial Solar System ¹⁴⁶Sm/¹⁴⁴Sm ratio (i.e., at 4568 Ma) of 0.0084±0.0003. The ¹⁷⁶Lu-¹⁷⁶Hf isotope systematics in these angrites do not provide evidence of a previously proposed intense irradiation event in the early Solar System. The internal ¹⁷⁶Lu-¹⁷⁶Hf isochrons for the NWA 4590 and D’Orbigny angrites provide an estimate for the Solar System initial ¹⁷⁶Hf/¹⁷⁷Hf ratio of 0.279775±0.000031 (2σ) that agrees within uncertainty with the value of average chondrites reported by Bouvier et al. (2008). Finally, the calculated initial 87Sr/86Sr ratios based on the measured Sr-isotopic composition of plagioclase in these angrites yield an estimated initial ⁸⁷Sr/⁸⁶Sr ratio of 0.698980±0.000011 for the angrite parent body. This is indistinguishable from a recently determined value for the Solar System initial ⁸⁷Sr/⁸⁶Sr based on values measured in calcium-aluminum-rich inclusions (CAIs) after correcting for nucleosynthetic effects in the CAIs. The low initial ⁸⁷Sr/⁸⁶Sr of the angrite parent body implies that it acquired its volatile element depleted characteristic within 1.8 Ma of Solar System formation, likely because it accreted from volatile depleted planetesimals that formed in the hot inner nebula. These integrated isotopic systematics suggest a complex history for the angrite parent body not previously inferred from short-lived chronometers and provide new estimates for the initial isotopic composition of the early Solar System.

Reference
Brown SM, Grove TL (2015) ^147,146Sm-^143,142Nd, ¹⁷⁶Lu-¹⁷⁶Hf, and ⁸⁷Rb-⁸⁷Sr Systematics in the Angrites: Implications for Chronology and Processes on the Angrite Parent Body. Geochimica et Cosmochimica Acta (in Press)
Link to Article [ http://www.sciencedirect.com/science/article/pii/S001670371500530X]
Copyright Elsevier

V. Al-Lagoa, M. Delbó, and G. Libourel
Laboratoire Lagrange, UMR7293, University de la Cote d’Azur, CNRS, Observatoire de la Cote d’Azur, F-06304 Nice Cedex 4, France

The so-called “early activity” of comet 67P/Churyumov?Gerasimenko has been observed to originate mostly in parts of the concave region or “neck” between its two lobes. Since activity is driven by the sublimation of volatiles, this is a puzzling result because this area is less exposed to the Sun and is therefore expected to be cooler on average. We used a thermophysical model that takes into account thermal inertia, global self-heating, and shadowing, to compute surface temperatures of the comet. We found that, for every rotation in the 2014 August?December period, some parts of the neck region undergo the fastest temperature variations of the comet’s surface precisely because they are shadowed by their surrounding terrains. Our work suggests that these fast temperature changes are correlated to the early activity of the comet, and we put forward the hypothesis that erosion related to thermal cracking is operating at a high rate on the neck region due to these rapid temperature variations. This may explain why the neck contains some ice?as opposed to most other parts of the surface?and why it is the main source of the comet’s early activity. In a broader context, these results indicate that thermal cracking can operate faster on atmosphereless bodies with significant concavities than implied by currently available estimates.

Reference
Al-Lagoa V, Delbó M and Libourel G (2015) Rapid temperature changes and the early activity on comet 67P/Churumov-Gerasimenko. Astrophysical Journal 810 L22 (in Press)
Link to Article [ http://iopscience.iop.org/article/10.1088/2041-8205/810/2/L22]

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