A geologically supervised spectral analysis of 121 globally distributed impact craters as a tool for identifying vertical and horizontal heterogeneities in the composition of the shallow crust of Mercury

1Piero D Incecco, 1Jörn Helbert, 1Mario D Amore, 1Sabrina Ferrari, 2James W. Head, 1Alessandro Maturilli,3Harald Hiesinger
Planetary and Space Science (in Press) Link to Article [http://dx.doi.org/10.1016/j.pss.2016.08.004]
1Institute of Planetary Research, German Aerospace Center, Rutherfordstrasse 2, D-12489 Berlin, Germany
2Department of Geological Sciences, Brown University, Providence, RI 02912, USA
3Westfälische Wilhelms-Universität Münster, Institut für Planetologie, Wilhelm-Klemm Str. 10, D-48149 Münster, Germany

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

Microstructures, mineral chemistry, noble gases and nitrogen in the recent fall, Bhuka iron (IAB) meteorite

1S.V.S. Murty, 1P.M. Ranjith, 1Dwijesh Ray, 1S. Ghosh, 2Basab Chattopadhyay, 3K.L. Shrivastava
Planetary and Space Science (in Press) Link to Article [http://dx.doi.org/10.1016/j.pss.2016.08.007]
1Planetary Sciences Division, Physical Research Laboratory, Ahmedabad, India
2Geological Survey of India, Kolkata
3Department of Geology, JNV University, Jodhpur, India

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

Automatic, Exploratory Mineralogical Mapping of CRISM Imagery Using Summary Product Signatures

1Elyse Allender, 1Tomasz F. Stepinski
Icarus (in Press) Link to Article [http://dx.doi.org/10.1016/j.icarus.2016.08.022]
1Space Informatics Lab, University of Cincinnati, Cincinnati, OH 45221-0131, USA
Copyright Elsevier

Martian spectroscopic and mineralogical analysis is usually performed using Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) browse products – false color images which show the spatial distribution of absorption features at key wavelengths. This manual, time-consuming method is ill-suited for exploratory surveys of a large number of images – for such surveys an automatic methodology is needed. In this paper we propose a method for exploratory but fully automatic mineralogical mapping of CRISM images. In our approach pixels are characterized by vectors of CRISM summary product values instead of spectral functions, and mineralogical units are discovered using a clustering principle. Moreover, the rare class discovery algorithm DEMUD is used in place of a standard clustering algorithm to identify mineralogical units – enabling the identification of only scientifically interesting, possibly rare, mineralogical deposits. The method outputs a map for each site showing the spatial distribution of mineralogical units – areas characterized by similar mineralogy. It also provides, without using a spectral library, semantic labels for each unit. We envision our method as a focus-of-attention tool to facilitate fast exploratory surveys of a large number of images. An analyst needs only to examine manually regions within an image where our pipeline indicates the existence of mineral units of interest. In this paper the method for our computational pipeline is described in detail and its performance is evaluated using a sample of 20 CRISM images – the mineralogical content of which is known from manual analysis. We find that our pipeline identifies most deposits found through manual analysis as well as some additional deposits which were not targeted by those analyses. Overall, we conclude that our fully automatic mineralogical mapper works well for exploratory purposes. Thus, it adds a new, valuable functionality to existing tools for CRISM imagery analysis.

In situ oxygen isotope compositions in olivines of different types of cosmic spherules: an assessment of relationships to chondritic particles

1N.G. Rudraswami, 1M. Shyam Prasad, 2R.H. Jones, 3K. Nagashima
Geochimica et Cosmochimica Acta (in Press)   Link to Article [http://dx.doi.org/10.1016/j.gca.2016.08.024]
1National Institute of Oceanography (Council of Scientific and Industrial Research), Dona Paula, Goa 403004, India
2School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
3Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, 1680 East-West-Road, Honolulu, HI 96822, USA
Copyright Elsevier

Cosmic spherules collected from deep sea sediments of the Indian Ocean having different textures such as scoriaceous (4), relict-bearing (16), porphyritic (35) and barred olivine (2) were investigated for petrography, as well as high precision oxygen isotopic studies on olivine grains using secondary ion mass spectrometry (SIMS). The oxide FeO/MgO ratios of large olivines (> 20μm) in cosmic spherules have low values similar to those seen in the olivines of carbonaceous chondrite chondrules, rather than matching the compositions of matrix. The oxygen isotope compositions of olivines in cosmic spherules have a wide range of δ18O, δ17O and Δ17O values as follows: −9 to 40‰, −13 to 22‰ and -11 to 6‰. Our results suggest that the oxygen isotope compositions of the scoriaceous, relict-bearing, porphyritic and barred spherules show provenance related to the carbonaceous (CM, CV, CO and CR) chondrites. The different types of spherules that has experienced varied atmospheric heating during entry has not significantly altered the Δ17O values. However, one of the relict-bearing spherules with a large relict grain has Δ17O = 5.7‰, suggesting that it is derived from 16O-poor material that is not recognized in the meteorite record. A majority of the spherules have Δ17O ranging from −4 to −2‰, similar to values in chondrules from carbonaceous chondrites, signifying that chondrules of carbonaceous chondrites are the major contributors to the flux of micrometeorites, with an insignificant fraction derived from ordinary chondrites. Furthermore, barred spherule data shows that during atmospheric entry an increase in ∼10‰ of δ18O value surges Δ17O value by ∼1‰.

The Astrobiology Primer v2.0

1,2Shawn D. Domagal-Goldman et al. (>10)*
Astrobiology 16, 8 561-653 Link to Article [doi:10.1089/ast.2015.1460]
1NASA Goddard Space Flight Center, Greenbelt, Maryland, USA.
2Virtual Planetary Laboratory, Seattle, Washington, USA.
*Find the extensive, full author and affiliation list on the publishers website

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

SEM morphological studies of carbonates and the search for ancient life on Mars

1M. D’Elia, 1A. Blanco, 1A. Galiano, 1V. Orofino, 1S. Fonti, 1F. Mancarella, 2A. Guido, 2F. Russo, 2A. Mastandrea
International Journal of Astrobiology (in Press) Link to Article [ http://dx.doi.org/10.1017/S147355041600015X]
1Department of Mathematics and Physics ‘Ennio De Giorgi’, University of Salento, Lecce, Italy
2Department of Biology, Ecology and Earth Science, University of Calabria, Cosenza, Italy

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

Formation of liquid water at low temperatures via the deliquescence of calcium chloride: Implications for Antarctica and Mars

1R.V. Gough, 2V.F. Chevrier, 1M.A. Tolbert
Planetary and Space Science (in Press) Link to Article [http://dx.doi.org/10.1016/j.pss.2016.07.006]
1Department of Chemistry and Biochemistry and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, 216 UCB, Boulder, CO 80309, USA
2Arkansas Center for Space and Planetary Sciences, University of Arkansas, Fayetteville, AR, USA

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

Temperature-dependent VNIR spectroscopy of hydrated Mg-sulfates

1S. De Angelis, 1C. Carli, 1F. Tosi, 2P. Beck, 2B. Schmitt, 1G. Piccioni, 1M.C. De Sanctis, 1F. Capaccioni, 3T. Di Iorio, 2Sylvain Philippe
Icarus (in Press) Link to Article [http://dx.doi.org/10.1016/j.icarus.2016.07.022]
1Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via del Fosso del Cavaliere 100, I-00133 Roma, Italy
2Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), 414 Rue de la Piscine, F-38400 St-Martin d’Hères (France), France
3ENEA Centro Ricerche Casaccia (ENEA SSPT-PROTER-OAC), Via Anguillarese 301, I-00123 Roma, Italy
Copyright Elsevier

We investigate two poly-hydrated magnesium sulfates, hexahydrite (MgSO4 • 6H2O) and epsomite (MgSO4 • 7H2O), in the visible and infrared (VNIR) spectral range 0.5÷4.0 μm, as particulate for three different grain size ranges: 20-50 µm, 75-100 µm and 125-150 µm. All samples were measured in the 93 K to 298 K temperature range. The spectra of these hydrated salts are characterized by strong OH absorption bands in the 1.0-1.5 μm region, and by H2O absorption bands near 2 and 3 μm. Other weak features show up at low temperatures near 1.75 μm (in both hexahydrite and epsomite) and 2.2 μm (only in hexahydrite). The spectral behavior of the absorption bands of these two minerals has been analyzed as a function of both grain size and temperature, deriving trends related to specific spectral parameters such as band center, band depth, band area, and band width. Hydrated minerals, in particular mono- and poly-hydrated sulfates, are present in planetary objects such as Mars and the icy Galilean satellites. Safe detection of these minerals shall rely on detailed laboratory investigation of these materials in different environmental conditions. Hence an accurate spectral analysis of such minerals as a function of temperature is key to better understand and constrain future observations.