Icarus (4), JGR-Planets (4), A&A (2), Nature (2), GCA (1), ApJ (1), EPSL (1), EPS (2), CDE (1)
Total: 20

Léveillé RJ et al. (2014) Chemistry of fracture-filling raised ridges in Yellowknife Bay, Gale Crater: window into past aqueous activity and habitability on Mars. Journal of Geophysical Research Planets (in Press)
Link to Article

Palme H, Spettel B, Hezel D (2014) Siderophile elements in chondrules of CV chondrites. Chemie der Erde (in Press)
Link to Article

Farrand WH, Glotch TD, Horgan B (2014) Detection of Copiapite in the northern Mawrth Vallis Region of Mars: Evidence of acid sulfate Alteration. Icarus, in Press
Link to Article

Keller LP, Berger EL (2014) A transmission electron microscope study of Itokawa regolith grains. Earth, Planets and Space 66, 71
Link to Article

Madied JM (2014) Robotic systems for the determination of the composition of solar system materials by means of fireball spectroscopy. Earth, Planets and Space 66, 70
Link to Article

Nachon M, Clegg SM, Mangold N, Schröder S, Kah LC, Dromart G, Ollila A, Johnson JR, Oehler DZ, Bridges JC et al. (Accepted) Calcium sulfate veins characterized by ChemCam/Curiosity at Gale Crater, Mars Journal of Geophysical Research: Planets 2169-9100
Link to Article

Prissel TC, Parman SW, Jackson CRM, Rutherford MJ, Hess PC, Head JW, Cheek L, Dhingra D and Pieters CM (in press) Pink Moon: The petrogenesis of pink spinel anorthosites and implications concerning Mg-suite magmatism. Earth and Planetary Science Letters 403:144.
Link to Article

Hubbard A (in press) Explaining Mercury’s Density through Magnetic Erosion. Icarus
Link to Article

Clenet H, Jutzi M, Barrat J-A, Asphaug EI, Benz W and Gillet P (2014) A deep crust–mantle boundary in the asteroid 4 Vesta. Nature 511:303.
Link to Article

Gall et al. (2014) Rapid formation of large dust grains in the luminous supernova 2010jl. Nature 511:326.
Link to Article

Schäfer et al. (in press) Imprint of the Rheasilvia Impact on Vesta – Geologic Mapping of Quadrangles Gegania and Lucaria. Icarus
Link to Article

Ronco  MP and de Elía GC (2014) Diversity of planetary systems in low-mass disks:Terrestrial-type planet formation and water delivery. Astronomy & Astrophysics 567:A54.
Link to Article

Donaldson Hanna KL, Cheek LC, Pieters CM, Mustard JF, Greenhagen BT, Thomas IR and Bowles NE (in press) Global assessment of pure crystalline plagioclase across the Moon and implications for the evolution of the primary crust. Journal of Geophysical Research: Planets
Link to Article

Williams DA, Jaumann R, McSween Jr. HY, Marchi S, Schmedemann N, Raymond CA and Russell CT (in press) The chronostratigraphy of protoplanet vesta. Icarus
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Gry C and Jenkins EB (2014) The interstellar cloud surrounding the Sun: a new perspective. Astronomy & Astrophysics
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Xiao Z, Zeng Z, Li Z, Blair DM and Xiao L (in press) Cooling fractures in impact melt deposits on the Moon and Mercury: Implications for cooling solely by thermal radiation. Journal of Geophysical Research: Planets
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Udry A, Lunning NG, McSween JR. HY and Bodnar RJ (in press) Petrogenesis of a vitrophyre in the martian meteorite breccia NWA 7034. Geochimica et Cosmochimica Acta
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Farnocchia D, Chesley SR, Chodas PW, Tricarico P, Kelley MSP and Farnham TL (2014) Trajectory Analysis for the Nucleus and Dust of Comet C/2013 A1 (Siding Spring). The Astrophysical Journal 790:114.
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^1,2Richard J. Léveillé et al.*
*Find the extensive, full author and affiliation list on the publishers Website.

¹Canadian Space Agency, Saint-Hubert, Quebec, Canada

²McGill University, Montreal, Quebec

The ChemCam instrument package on the Curiosity rover was used to characterize distinctive raised ridges in the Sheepbed mudstone, Yellowknife Bay formation, Gale Crater. The multilayered, fracture-filling ridges are more resistant to erosion than the Sheepbed mudstone rock in which they occur. The bulk average composition of the raised ridges is enriched in MgO by 1.2-1.7 times (average of 8.3-11.4 wt %; single shot maximum of 17.0 wt %) over that of the mudstone. Al2O3 is anti-correlated with MgO, while Li is somewhat enriched where MgO is highest. Some ridges show a variation in composition with different layers on a sub-mm scale. In particular, the McGrath target shows similar high-MgO resistant outer layers and a low-MgO, less resistant inner layer. This is consistent with the interpretation that the raised ridges are isopachous fracture-filling cements with a stratigraphy that likely reveals changes in fluid composition or depositional conditions over time. Overall, the average composition of the raised ridges is close to that of a Mg- and Fe-rich smectite, or saponite, which may also be the main clay mineral constituent of the host mudstone. These analyses provide evidence of diagenesis and aqueous activity in the early post-depositional history of the Yellowknife Bay formation, consistent with a low salinity to brackish fluid at near-neutral or slightly alkaline pH. The fluids that circulated through the fractures likely interacted with the Sheepbed mudstone and (or) other stratigraphically adjacent rock units of basaltic composition and leached Mg from them preferentially.

Reference
Léveillé RJ et al. (2014) Chemistry of fracture-filling raised ridges in Yellowknife Bay, Gale Crater: window into past aqueous activity and habitability on Mars. Journal of Geophysical Research Planets (in Press)

Link to Article [DOI: 10.1002/2014JE004620]

Published by arrangement with John Wiley & Sons

¹Herbert Palme, ²Bernhard Spettel, ^3,4Dominik Hezel

¹Forschungsinstitut und Naturmuseum Senckenberg, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany
²An den 18 Morgen 10, 55127 Mainz, Germany
³Institut für Geologie und Mineralogie, Universität zu Köln, Zülpicherstrasse 49b, D-50674 Köln, Germany
⁴Natural History Museum, Department of Mineralogy, Cromwell Road, SW7 5BD London, UK

New bulk compositional data for 34 Allende chondrules are presented. Whole chondrules were analyzed by instrumental neutron activation analysis (INAA). The new data set is evaluated together with older INAA data on Allende chondrules and recent INAA data on Mokoia chondrules. The Ni/Co ratios of 200 chondrules are close to the CI- or solar ratio. The chondritic Ni/Co ratios require an unfractionated chondritic metal source and set a limit to the fraction of metal lost from molten chondrules. The bulk chondrule Fe/Ni and Fe/Co ratios are more variable but on average chondritic. Iridium and other refractory metals have extremely variable concentrations in chondrules. High Ir chondrules have chondritic Ir/Sc ratios. They are dominated by CAI (Ca,Al-rich inclusion) components. Low Ir chondrules have approximately chondritic Ir/Ni ratios reflecting mixing with chondritic metal. In low Ir chondrules Ir correlates and in high Ir chondrules Ir does not correlate with Ni or Co. A large fraction of Ir may have entered chondrules in variable amounts as tiny grains of refractory metal alloys.

Most Allende chondrules have Ir/Sc ratios below bulk meteorite ratios. Matrix must have a complementary high Ir/Sc ratio, as bulk Allende has approximately chondritic Ir/Sc ratio. Similarly, the high average Ir/Ni ratios of Allende chondrules must be balanced by low Ir/Ni ratios in matrix to obtain the bulk Allende Ir/Ni ratio, which is close to the average solar system ratio.

More recent data on single chondrules from Allende by ICP-MS (Inductively Coupled Plasma Mass Spectrometry) and ICP-OES (Inductively Coupled Optical Emission Spectrometry) show the same trends as the INAA data discussed here.

Reference

Palme H, Spettel B, Hezel D (2014) Siderophile elements in chondrules of CV chondrites. Chemie der Erde (in Press)

Link to Article [DOI: 10.1016/j.chemer.2014.06.003]

Copyright Elsevier

¹W.H. Farrand, ²T.D. Glotch, ³B. Horgan

¹Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO, 80301
²Department of Geosciences, Stony Brook University, Stony Brook, NY, 11794
³Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, W. Lafayette, IN, 47907

The Mawrth Vallis region on Mars is associated with extensive layered deposits containing a stratigraphic sequence of Fe/Mg smectites overlain by Al phyllosilicates. Earlier studies have reported restricted exposures of the ferric sulfate mineral jarosite on top of the sequence. In this paper we have used CRISM data covering the northern portion of the Mawrth Vallis region to find a new jarosite exposure and multiple occurrences of the mixed valence Fe-sulfate mineral copiapite (Fe²⁺Fe³⁺₄(SO₄)₆(OH)₂⋅ 20(H₂O)). HiRISE imagery indicate that the copiapite exposures lie on top of the Al phyllosilicates and thus post-date that unit either as a coating or as extensive veins. The presumed copiapite exposures are associated with high values of a “SINDX” parameter derived from CRISM data. Application of several spectral matching metrics over a spectral subsection indicated several candidates for the high SINDX phase including copiapite, ferricopiapite and metavoltine (another mixed valence Fe-sulfate mineral). Visible and near infrared CRISM spectra of the high SINDX areas are most consistent with the phase being copiapite. On Earth copiapite generally occurs as efflorescent coatings in acid mine drainage environments or in association with acid sulfate soils. The presence of jarosite and copiapite indicates the presence of acidic waters. Such acid waters could have contributed to the formation of the underlying Al phyllosilicate minerals. A possible mode of origin for these minerals in this region would involve a fluctuating ground water table and the weathering of Fe sulfide minerals.

Reference

Farrand WH, Glotch TD, Horgan B (2014) Detection of Copiapite in the northern Mawrth Vallis Region of Mars: Evidence of acid sulfate Alteration. Icarus, in Press

Link to Article: [DOI: 10.1016/j.icarus.2014.07.003]

Copyright Elsevier

Lindsay P Keller¹ and Eve L Berger²

¹Robert M Walker Laboratory for Space Science, Code KR, Astromaterials
Research and Exploration Science, NASA Johnson Space Center, Houston, TX
77058, USA
²GeoControl Systems, Inc. – Jacobs JETS contract – NASA Johnson Space
Center, Houston, TX 77058, USA

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

Reference

Keller LP, Berger EL (2014) A transmission electron microscope study of Itokawa regolith grains. Earth, Planets and Space 66, 71

Link to Article [doi:10.1186/1880-5981-66-71]

José M Madied¹

¹Facultad de Ciencias Experimentales, Universidad de Huelva, Huelva 21071, Spain

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

Reference

Madied JM (2014) Robotic systems for the determination of the composition of solar system materials by means of fireball spectroscopy. Earth, Planets and Space 66, 70

Link to Article [doi:10.1186/1880-5981-66-70]

M.Nachon¹ et al. (>10)*
*Find the extensive, full author and affiliation list on the publishers website.

¹Laboratoire de Planétologie et Géodynamique de Nantes, CNRS, UMR6112, Université de Nantes, Nantes, France

The Curiosity rover has analyzed abundant light-toned fracture-fill material within the Yellowknife Bay sedimentary deposits. The ChemCam instrument, coupled with Mastcam and ChemCam/Remote Micro Imager images, was able to demonstrate that these fracture fills consist of calcium sulfate veins, many of which appear to be hydrated at a level expected for gypsum and bassanite. Anhydrite is locally present, and is found in a location characterized by a nodular texture. An intricate assemblage of veins crosses the sediments, which were likely formed by precipitation from fluids circulating through fractures. The presence of veins throughout the entire ~5 m thick Yellowknife Bay sediments suggests that this process occurred well after sedimentation and cementation/lithification of those sediments. The sulfur-rich fluids may have originated in previously precipitated sulfate-rich layers, either before the deposition of the Sheepbed mudstones, or from unrelated units such as the sulfates at the base of Mount Sharp. The occurrence of these veins after the episodes of deposition of fluvial sediments at the surface suggests persistent aqueous activity in relatively non-acidic conditions.

Reference

Nachon M, Clegg SM, Mangold N, Schröder S, Kah LC, Dromart G, Ollila A, Johnson JR, Oehler DZ, Bridges JC et al. (Accepted) Calcium sulfate veins characterized by ChemCam/Curiosity at Gale Crater, Mars
Journal of Geophysical Research: Planets 2169-9100

Link to Article [DOI: 10.1002/2013JE004588]

Published by arrangement with John Wiley & Sons

T.C. Prissel, S.W. Parman, C.R.M. Jackson, M.J. Rutherford, P.C. Hess, J.W. Head, L. Cheek, D. Dhingra, C.M. Pieters

Department of Earth, Environmental & Planetary Sciences, Brown University, Providence, RI 02912, USA

NASA’s Moon Mineralogy Mapper (M³) has identified and characterized a new lunar rock type termed pink spinel anorthosite (PSA) (Pieters et al., 2011). Dominated by anorthitic feldspar and rich in MgAl₂O₄ spinel, PSA appears to have an unusually low modal abundance of mafic silicates, distinguishing it from known lunar spinel-bearing samples. The interaction between basaltic melts and the lunar crust and/or assimilation of anorthitic plagioclase have been proposed as a possible mechanism for PSA formation (Gross and Treiman, 2011 and Prissel et al., 2012). To test these hypotheses, we have performed laboratory experiments exploring magma–wallrock interactions within the lunar crust. Lunar basaltic melts were reacted with anorthite at 1400 °C and pressures between 0.05–1.05 GPa. Results indicate that PSA spinel compositions are best explained via the interaction between Mg-suite parental melts and anorthositic crust. Mare basalts and picritic lunar glasses produce spinels too rich in Fe and Cr to be consistent with the M³ observations.
The experiments suggest that PSA represents a new member of the plutonic Mg-suite. If true, PSA can be used as a proxy for spectrally identifying areas of Mg-suite magmatism on the Moon. Moreover, the presence of PSA on both the lunar nearside and farside (Pieters et al., in press) indicates Mg-suite magmatism may have occurred on a global scale. In turn, this implies that KREEP is not required for Mg-suite petrogenesis (as KREEP is constrained to the nearside of the Moon) and is only necessary to explain the chemical make-up of nearside Mg-suite samples.

Reference
Prissel TC, Parman SW, Jackson CRM, Rutherford MJ, Hess PC, Head JW, Cheek L, Dhingra D and Pieters CM (in press) Pink Moon: The petrogenesis of pink spinel anorthosites and implications concerning Mg-suite magmatism. Earth and Planetary Science Letters 403:144.
[doi:10.1016/j.epsl.2014.06.027]
Copyright Elsevier

Link to Article

Alexander Hubbard

Department of Astrophysics, American Museum of Natural History, New York, NY 10024-5192, USA

In protoplanetary disks, dust grains rich in metallic iron can attract each other magnetically. If they are magnetized to values near saturation, the magnetically induced collision speeds are high enough to knock off the non-magnetized, loosely bound silicates. This process enriches the surviving portions of the dust grains in metallic iron, which further enhances the magnetically mediated collisions. The magnetic enhancement to the collisional cross-section between the iron rich dust results in rapid grain growth leading to planetesimal formation. While this process of knocking off silicates, which we term “magnetic erosion”, occurs only in a very limited portion of a protoplanetary disk, it is a possible explanation for Mercury’s disproportionately large iron core.

Reference
Hubbard A (in press) Explaining Mercury’s Density through Magnetic Erosion. Icarus
[doi:10.1016/j.icarus.2014.06.032]
Copyright Elsevier

Link to Article

Harold Clenet^a, Martin Jutzi^b, Jean-Alix Barrat^c, Erik I. Asphaug^c, Willy Benz^b and Philippe Gillet^a

^aEPSL, Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
^bPhysics Institute, Space Research and Planetary Sciences, Center for Space and Habitability, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
^cUniversité de Bretagne Occidentale, Institut Universitaire Européen de la Mer, CNRS UMR 6538, Place Nicolas Copernic, 29280 Plouzané, France
^dSchool of Earth and Space Exploration, Arizona State University, PO Box 876004, Tempe, Arizona 85287, USA

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

Reference
Clenet H, Jutzi M, Barrat J-A, Asphaug EI, Benz W and Gillet P (2014) A deep crust–mantle boundary in the asteroid 4 Vesta. Nature 511:303.
[doi:10.1038/nature13499]

Link to Article