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
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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.
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Hubbard A (in press) Explaining Mercury’s Density through Magnetic Erosion. Icarus
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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.
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Gall et al. (2014) Rapid formation of large dust grains in the luminous supernova 2010jl. Nature 511:326.
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Schäfer et al. (in press) Imprint of the Rheasilvia Impact on Vesta – Geologic Mapping of Quadrangles Gegania and Lucaria. Icarus
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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.
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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
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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]