^1,2Poorna Srinivasan, ³Daniel R. Dunlap, ^1,2Carl B. Agee, ³Meenakshi Wadhwa, ⁴Daniel Coleff, ^1,2Karen Ziegler, ⁵Ryan Zeigler, ⁵Francis M. McCubbin
Nature Communications 9, 3036 Link to Article [https://doi.org/10.1038/s41467-018-05501-0]
¹Institute of Meteoritics, University of New Mexico, Albuquerque, NM, 87131, USA
²Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, 87131, USA
³Center for Meteorite Studies, School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287, USA
⁴Jacobs Technology, NASA Johnson Space Center, Mail Code XI3, 2101 NASA Parkway, Houston, TX, 77058, USA
⁵NASA Johnson Space Center, Mail Code XI2, 2101 NASA Parkway, Houston, TX, 77058, USA

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¹Z. Dionnet,¹A. Aleon‐Toppani,¹D. Baklouti,²F. Borondics,³F. Brisset,¹Z. Djouadi,²C. Sandt,¹R. Brunetto
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13178]
¹Institut d’Astrophysique Spatiale, CNRS, Université Paris‐Sud, Université Paris‐Saclay, Orsay Cedex, France
²Synchrotron SOLEIL, l’Orme des Merisiers, Saint‐Aubin, France
³Institut de Chimie Moléculaire et des Matériaux d’Orsay, Université Paris Sud, Université Paris‐Saclay, Orsay Cedex, France
Published by arrangement with John Wiley & Sons

Significant compositional and structural heterogeneity at nm to mm scales is an important characteristic of primitive extraterrestrial materials. Here, we report the analysis of high‐resolution Fourier transform IR hyperspectral imaging analytical measurements at the micron scale on a fragment of the Paris carbonaceous chondrite, supported by Raman and SEM‐EDS measurements. The fragment is crushed in a diamond compression cell. The micro‐FTIR analyses are performed in transmission with two setups, an imaging microscope with a matrix detector using a thermal source and a system using a single point detector coupled with the synchrotron source at the SOLEIL synchrotron facility. We obtain the spatial distribution of chemical/mineralogical components. We confirm at a larger scale (10 μm) the presence of hydrated amorphous silicates observed at a smaller scale (1 μm). Based on the relative abundance of different minerals (hydrated amorphous silicate, olivine, diopside, and serpentine), we propose a sequence of aqueous alteration. Considering the spatial correlation of minerals with organic matter, we discuss the effects of aqueous alteration on the organic matter in bulk. In particular, we detect an increase in the CH2/CH3 ratio in the altered zone and present the possible scenarios that led to the observed chain length shortening/cracking of hydrocarbons.

¹Alan E. Rubin
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13180]
¹Department of Earth, Planetary and Space Sciences, University of CaliforniaLos Angeles, California, USA
²Maine Mineral & Gem Museum, Bethel, Maine, USA
Published by arrangement with John Wiley & Sons

Although they cannot be ruled out, high partial pressures of SiO(g) in the solar nebula are not required to produce various petrologic features of chondrules. These features include the low‐Ca‐pyroxene‐rich margins of type‐IAB chondrules, high concentrations of SiO2 and Na2O in mesostasis near the surface of some chondrules in LL3.0 Semarkona, and silica‐rich igneous rims around many type‐I chondrules in CR chondrites. It is a misconception that low‐Ca pyroxene phenocrysts are restricted mainly to the periphery of type‐IAB chondrules; instead, they are widely distributed in most of these chondrules. Type‐IAB chondrules can be modeled as having formed by remelting of type‐IB chondrules that contained relict olivine grains derived from disrupted type‐IA chondrules. Semarkona chondrule mesostases that show increased concentrations of SiO2 and Na2O from the core to the rim were probably affected by parent‐body aqueous alteration. The silica‐rich igneous rims around many type‐I chondrules in CR chondrites may have formed by melting of pyroxene‐rich dust aggregates that had been previously enriched in Na, K, and Mn derived from volatilized chondrules.

¹Chi Ma, ²Alexander N. Krot
American Mineralogist 103, 1329-1334 Link to Article [https://doi.org/10.2138/am-2018-6505]
¹Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, U.S.A.
²Hawai‘i Institute of Geophysics and Planetology, University of Hawai‘i at Mānoa, Honolulu, Hawai‘i 96822, U.S.A.
Copyright: The Mineralogical Society of America

Adrianite (IMA 2014-028), Ca12(Al4Mg3Si7)O32Cl6, is a new Cl-rich silicate mineral and the Si,Mg analog of wadalite. It occurs with monticellite, grossular, wadalite, and hutcheonite in altered areas along some veins between primary melilite, spinel, and Ti,Al-diopside in a Type B1 FUN (Fractionation and Unidentified Nuclear effects) Ca-Al-rich inclusion (CAI), Egg-3, from the Allende CV3 carbonaceous chondrite. The mean chemical composition of type adrianite by electron probe microanalysis is (wt%) CaO 41.5, SiO2 27.5, Al2O3 12.4, MgO 7.3, Na2O 0.41, Cl 13.0, O=Cl –2.94, total 99.2, giving rise to an empirical formula of (Ca11.69Na0.21)(Al3.85Mg2.88Si7.23)O32Cl5.80. The end-member formula is Ca12(Mg5Si9)O32Cl6. Adrianite has the I43d wadalite structure with a = 11.981 Å, V = 1719.8 Å3, and Z = 2, as revealed by electron backscatter diffraction. The calculated density using the measured composition is 3.03 g/cm3. Adrianite is a new secondary mineral in Allende, apparently formed by alkali-halogen metasomatic alteration of primary CAI minerals such as melilite, anorthite, perovskite, and Ti,Al-diopside on the CV chondrite parent asteroid. Formation of secondary Cl-rich minerals sodalite, adrianite, and wadalite during metasomatic alteration of the Allende CAIs suggests that the metasomatic fluids had Cl-rich compositions. The mineral name is in honor of Adrian J. Brearley, mineralogist at the University of New Mexico, U.S.A., in recognition of his many contributions to the understanding of secondary mineralization in chondritic meteorites.

¹Matthew A.Pasek
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2018.07.011]
¹School of Geosciences, University of South Florida, 4202 E. Fowler Ave NES 204, Tampa, FL 33620, USA
Copyright Elsevier

Phosphorus is a minor element that controls the formation of several key planetary minerals. It is also an element critical to the development of life. A common assumption of phosphorus chemistry is that at low temperatures, phosphorus would have been a volatile component of ices or gases in the outer Solar System. Here I propose that phosphorus was depleted as a volatile throughout the developing Solar System, and as a result, volatile forms of phosphorus would have been minimal, even in the colder regions of the Solar nebula. Based on thermodynamic equilibrium models and metal phosphidation kinetics coupled to a simple 1D gas diffusion model, phosphorus migrated rapidly to the inner Solar System, forming solids such as phosphides and phosphates, and removing volatile phosphorus across large portions of the Solar System.

¹Kelsey B.Prissel, ¹Michael J.Krawczynski, ²Nicole X.Nie, ²Nicolas Dauphas, ¹Hélène Couvy, ³Michael Y.Hu, ³E.Ercan Alp, ⁴Mathieu Roskosz
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2018.07.028]
¹McDonnell Center for the Space Sciences and Department of Earth and Planetary Sciences, Washington University in St. Louis, 1 Brookings Drive, St. Louis, MO 63123
²Origins Laboratory, Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60637
³Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439
⁴IMPMC, CNRS UMR 7590, Sorbonne Universités, Université Pierre et Marie Curie, IRD, Muséum National d’Histoire Naturelle, CP 52, 57 rue Cuvier, Paris F-75231, France
Copyright Elsevier

Olivine is the most abundant mantle mineral at depths relevant to oceanic crust production through melting. It is also a liquidus phase for a wide range of mafic and ultramafic magma compositions. We have experimentally investigated the effects of olivine crystallization and melt composition on the fractionation of Fe isotopes in igneous systems. To test whether there is a melt compositional control on Fe isotopic fractionation, we have conducted nuclear resonant inelastic X-ray scattering (NRIXS) measurements on a suite of synthetic glasses ranging from 0.4 to 16.3 wt.% TiO2. The resulting force constants are similar to those of the reduced (fO2 = IW) terrestrial basalt, andesite, and dacite glasses reported by Dauphas et al. (2014), indicating that there is no measurable effect of titanium composition on Fe isotopic fractionation in the investigated compositional range. We have also conducted olivine crystallization experiments and analyzed the Fe isotopic composition of the experimental olivines and glasses using solution MC-ICPMS. Olivine and glass separates from a given experimental charge have the same iron isotopic composition within error. This result is robust in both the high-Ti glass (Apollo 14 black) and low-Ti glass (Apollo 14 VLT) compositions, and at the two oxygen fugacities investigated (IW-1, IW+2). Additionally, we have determined that Fe loss in reducing one-atmosphere gas-mixing experiments occurs not only as loss to the Re wire container, but also as evaporative loss, and each mechanism of experimental Fe loss has an associated Fe isotopic fractionation.
We apply our results to interpreting Fe isotopic variations in the lunar mare basalts and lunar dunite 72415-8. Our experimental results indicate that neither melt TiO2 composition nor equilibrium olivine crystallization can explain the observed difference in the iron isotopic composition of the lunar mare basalts. Additionally, equilibrium iron isotopic fractionation between olivine and melt cannot account for the “light” iron isotopic composition of lunar dunite 72415-8, unless the melt from which it is crystallizing was already enriched in light iron isotopes. Our results support models of diffusive fractionation to explain the light iron isotopic compositions measured in olivine from a variety of rock types and reduced (fO2 = IW-1 to IW+2) igneous environments (e.g., lunar dunite and basalts, terrestrial peridotites and basalts, martian shergottites).

¹Gordon R. Oskinsi et al. (>10)
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2018.07.011]
¹Centre for Planetary Science and Exploration, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada
²Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada
³Department of Physics and Astronomy, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada
⁴Department of Electrical and Computer Engineering, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B9, Canada

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¹Joshua T.S.Cahill, ¹David T.Blewett, ²Nhan V.Nguyen, ²Alex Boosalis, ³Samuel J.Lawrence, ¹Brett W.Denevi
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2018.07.008]
¹Johns Hopkins Applied Physics Laboratory, Laurel, MD 20723, USA
²National Institute of Standards and Technology, Gaithersburg, MD, USA
³NASA-Johnson Space Center, Houston, TX, USA
Copyright Elsevier

We report new measurements of the optical constants of iron and nickel metal in the ultraviolet, visible, and near-infrared portions of the electromagnetic spectrum (∼0.16 to 3.59 μm), building upon the measurements of Cahill et al. (2012). These values were determined from metal films vapor-deposited onto fused-silica prisms. Our measurement of optical constants employed ellipsometry performed within the prism, sensing the side of the metal film unexposed to the ambient atmosphere. The data we report have important implications for modeling planetary reflectance and emittance spectra, especially in relation to space-weathering effects observed in remotely sensed data for the surfaces of the Moon, Mercury, and asteroids.

¹F.G.Carrozzo et al. (>10)
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2018.07.013]
¹Istituto di Astrofisica e Planetologia Spaziali, INAF, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
Copyright Elsevier

Quadrangle Ac-H-08 Nawish is located in the equatorial region of Ceres (Lat 22°S-22°N, Lon 144°E- 216°E), and it has variable mineralogy and geology. Here, we report on the mineralogy using spectra from the Visible and InfraRed (VIR) mapping spectrometer onboard the NASA Dawn mission. This quadrangle has two generally different regions: the cratered highlands of the central and eastern sector, and the eastern lowlands. We find this dichotomy is also associated with differences in the NH4-phyllosilicates distribution. The highlands, in the eastern part of the quadrangle, appear depleted in NH4-phyllosilicates, conversely to the lowlands, in the north-western side. The Mg-phyllosilicates distribution is quite homogeneous across Nawish quadrangle, except for few areas. The 2.7-µm band depth is lower in the south-eastern part, e.g. in the Azacca ejecta and Consus crater ejecta, and the band depth is greatest for the Nawish crater ejecta, and indicates the highest content of Mg-phyllosilicates of the entire quadrangle. Our analysis finds an interesting relationship between geology, mineralogy, topography, and the age in this quadrangle. The cratered terrains in the highlands, poor in NH4 phyllosilicates, are older (̴2 Ga). Conversely, the smooth terrain, such as with Vindimia Planitia, is richer in ammonia-bearing phyllosilicates and is younger (̴1 Ga). At the local scale, Ac-H-8 Nawish, displays several interesting mineralogical features, such as at Nawish crater, Consus crater, Dantu and Azzacca ejecta, which exhibit localized Na-carbonates deposits. This material is superimposed on the cratered terrains and smooth terrains and shows the typical depletion of phyllosilicates, already observed on Ceres in the presence of Na-carbonates.

¹Sara S. Russell, ²Harold C. Connolly Jr., ³Alexander N. Krot (Editors)
Cambridge University Press  Link to Book [doi.org/10.1017/9781108284073]
¹Natural History Museum, London
²Rowan University, New Jersey
³University of Hawaii, Manoa

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