Mars-rover cameras evaluation of laboratory spectra of Fe-bearing Mars analog samples

1Javier Cuadros,2Joseph R.Michalski,3Janice L.Bishop,1Christian Mavris,4Saverio Fiore,5Vesselin Dekov
Icarus (in Press) Link to Article []
1Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
2Department of Earth Sciences & Laboratory for Space Research, The University of Hong Kong, Hong Kong, China
3SETI Institute, Mountain View, CA 94043, USA
4Institute of Methodologies for Environmental Analysis, CNR, Department of Geoenvironmental and Earth Sciences, University of Bari, Via Orabona 4, 70125 Bari, Italy
5Department of Marine Resources and Energy, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
Copyright Elsevier

The cameras on the Pathfinder probe (Imager for Pathfinder) and the rovers Spirit and Opportunity (Panoramic Camera), Curiosity (Mast Camera) and Perseverance (Mast Camera-Z) produce visible-range spectra of limited wavelength resolution but of great target resolution which allows mineralogical analysis of selected areas within martian rocks. Laboratory spectra of relevant specimens were transformed into the spectra corresponding to each of the above cameras to increase our capability to interpret martian spectral data collected in-situ. The focus was on finding spectral features that can be detected by the cameras on Mars and are diagnostic of specific minerals. The samples are a collection of (1) Fe/Mg-phyllosilicates from submarine hydrothermal sites and (2) of rocks from acid alteration environments containing goethite, hematite, jarosite and Fe-bearing chlorite as these minerals are detectable in the extended visible range. Among all the samples, interstratified glauconite-nontronite has the most unique spectral features and should be easily detectable with the rover cameras. The spectral features of talc from Fe-bearing interstratified specimens are described. These data are especially relevant as glauconite and talc have been proposed to be fairly abundant on Mars and their detections are suggested from remote-sensing near-IR data. Several indices are proposed to assess Fe content on the investigated samples as well as mineral concentration of goethite and hematite. Among these indices, the normalized spectral slope in the range 420–600 nm increases with total Fe content for all samples, whether phyllosilicates, oxides or sulphates (R2 = 0.7–0.8). For pure phyllosilicates, the slope from 600 to 1010 nm decreases with increasing octahedral Fe (R2 = 0.75). An index for goethite produced excellent results assessing goethite concentration (R2 = 0.84). Of all cameras, Mast Camera reproduces the spectra with lowest fidelity and generates the poorest correlations between indices and tested variables. The other three cameras perform similarly.

Constraints on the petrologic history of gabbroic shergottite Northwest Africa 6963 from pyroxene zoning profiles and electron backscattered diffraction

1Andrea Wenzel,2Justin Filiberto,3Natasha Stephen,4Susanne P. Schwenzer,5Samantha J. Hammond
Meteoritics & Planetary Science (in Press) Link to Article []
1Department of Geology, Southern Illinois University, Carbondale, Illinois, 62901 USA
2Lunar and Planetary Institute, USRA, Houston, Texas, 77058 USA
3Plymouth Electron Microscopy Centre, University of Plymouth, Drake Circus, Plymouth, PL4 8AA UK
4AstrobiologyOU, School of Environment, Earth, and Ecosystems Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA UK
5School of Environment, Earth, and Ecosystems Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA UK
Published by arrangement with John Wiley & Sons

Northwest Africa 6963 (NWA 6963) is a coarse-grained, gabbroic Martian meteorite that further extends our Martian sample collection, both compositionally and texturally. Gabbroic shergottite NWA 6963 provides direct petrologic evidence of intrusive igneous conditions within the Martian crust. Here, we analyzed geochemical zoning profiles and microstructural-crystallographic information from electron backscattered diffraction of augite and pigeonite to constrain the crystallization history of NWA 6963. Compositional zoning profiles reveal pyroxenes with augite or pigeonite cores mantled by Fe-rich pigeonite rims. Our results suggest complex pyroxene textures and zoning profiles observed in pyroxenes in NWA 6963 are due to pyroxene accumulation from a crystallizing magma in a large intrusive environment (sill or magma chamber); however, without geologic context or companion samples, it is currently impossible to rule out accumulation at the base of a very large (>>100 m) differentiated flow.

Detection of an excessively strong 3-μm absorption near the lunar highland crater Dufay

1C. Wöhler,1A. Grumpe,2M. Bhatt,3A. A. Berezhnoy,3V. V. Shevchenko,2A. Bhardwaj
Astronomy & Astrophysics 630, L7 Link to Article []
1Image Analysis Group, TU Dortmund University, Otto-Hahn-Str. 4, 44227 Dortmund, Germany
2Physical Research Laboratory, Ahmedabad 380009, India
3Sternberg Astronomical Institute, Moscow State University, Universitetskij Pr., 13, 119234 Moscow, Russia

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

Miller Range 07687 and its place within the CM-CO clan

1Trygve Prestgard,1Lydie Bonal,1Jolantha Eschrig,2Jérôme Gattacceca,2Corinne Sonzogni,1Pierre Beck
Meteorics & Planetary Science (in Press) Link to Article []
1Institut de Planétologie et d’Astrophysique de Grenoble, Université Grenoble Alpes, CNRS CNES, 38000 Grenoble, France
2CNRS, Aix Marseille Univ, IRD, Coll France, INRA, CEREGE, Aix-en-Provence, France
Published by arrangement with John Wiley & Sons

Miller Range (MIL) 07687 is a peculiar carbonaceous chondrite officially classified as a CO3. However, it has been found to display unique petrographic properties that are atypical of this group. Moreover, Raman spectra of its polyaromatic carbonaceous matter do not reflect a structural order consistent with the metamorphic history of a type 3 chondrite. As a result, it has been suggested to be an ungrouped C2 chondrite with CO affinities, although it has not been fully excluded as a CO chondrite. The ambiguity of the meteorite’s classification is the motivation behind the present study. We conclude that MIL 07687 is a unique carbonaceous chondrite with possible affinities to CO, CM, and/or some ungrouped carbonaceous chondrites. The difficulty in classifying this meteorite stems from (1) its heavily weathered nature, which interferes with the interpretation of our oxygen (O-)isotopic measurements; (2) the overlap in the petrographic and O-isotopic descriptions of various COs, CMs, and ungrouped meteorites in the Meteoritical Society Database. Optical and infrared spectra are consistent with the meteorite’s unequilibrated nature and indicate that it is probably mildly aqueously altered. Despite traces of aqueous alteration having previously been described in MIL 07687, this is the first time that the presence of hydrated amorphous silicates is reported. In fact, our results show that its present hydration is beyond that of most CO3s, less than most CM2s, and comparable to primitive CR2s. Consequently, we support the meteorite’s C2-ung label, although a CO2 or CM2 classification cannot be fully excluded.

Long-lasting habitable periods in Gale crater constrained by glauconitic clays

1,2Elisabeth Losa-Adams,1,3Carolina Gil-Lozano,4,5Alberto G. Fairén,6,7Janice L. Bishop,7Elizabeth B. Rampe,1Luis Gago-Duport
Nature Astronomy 5, 936–942 Link to Article [DOI]
1Departamento de Geociencias Marinas, Universidade de Vigo, Lagoas-Marcosende, Vigo, Spain
2Centro de Investigación Mariña da Universidade de Vigo (CIM-UVIGO), Vigo, Spain
3Laboratoire de Planétologie et Géodynamique de Nantes (LPGN), CNRS/Université de Nantes, Nantes, France
4Centro de Astrobiología (CSIC-INTA), Torrejón de Ardoz, Madrid, Spain
5Department of Astronomy, Cornell University, Ithaca, NY, USA
6SETI Institute, Mountain View, CA, USA
7NASA Ames Research Center, Moffett Field, CA, USA

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

Metallographic Cooling Rate and Petrogenesis of the Recently Found Huoyanshan Iron Meteorite Shower

1,2Nian Wang,3,4Guiqin Wang,1,2Ting Zhang,1Lixin Gu,1Chi Zhang,1Sen Hu,5Bingkui Miao,1,2Yangting Lin
Journal of Geophysical Research (Planets) (In Press) Link to Article []
1Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029 China
2University of Chinese Academy of Sciences, Beijing, 100049 China
3State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640 China
4CAS Center for Excellence in Comparative Planetology, China
5Key Laboratory of Geological Engineering Center of Guangxi Province, Guilin University of Technology, Guilin, 541004 China
Published by arrangement with John Wiley & Sons

The Huoyanshan iron meteorite shower, recently found in the Gobi Desert of Hami, Xinjiang, China, has very high Ni (21.1 wt%) content and low Au (2.0 ppm), Ir (0.02 ppm), Ge (1.7 ppm), and Ga (1.1 ppm) contents, and was classified into IAB-sLH subgroup. The iron has a finest octahedrite structure of Widmanstätten pattern (the intergrowth of kamacite (α) and taenite (γ)) with plessite matrix, and euhedral schreibersite (Sch) crystals exclusively enclosed in kamacite bands. The textural features suggest the following formation process: γ→γ + Sch →γ+ Sch + α, and then γ→α2 + γ. The metallographic cooling rate of Huoyanshan iron was determined to be 3–50 °C/Myr using both the taenite Ni profile-matching and taenite central Ni content methods, with the bandwidths corrected for crystallographic orientation by electron backscatter diffraction (EBSD). The cooling rate of Huoyanshan is consistent with other sLH and confirms the slow cooling history of the IAB low-Au subgroups. The slow cooling rates of non-magmatic irons required immediate re-accretion with a thick brecciated fragments layer in the parent body after the impact melting event. The depleted but unfractionated Re, Os, Ir, Ru, and Pt and the enriched Pd and Au abundances of Huoyanshan iron and other sLH subgroup show complementary feature to that of refractory metal nuggets in Ca-, Al-rich inclusions (CAIs), which could be explained by extracting the metallic Fe-Ni with HSE predominantly remained in CAIs from a CAI-bearing asteroid. The very high Ni content of sLH subgroup suggests a highly oxidized parental asteroid, but non-carbonaceous chondrite based on Mo isotopic compositions (Worsham et al., 2017). We propose that the Huoyanshan iron and other sLH subgroup were produced by impact melting of a LL like and CAI-bearing asteroid, followed by fast burying of thick and porous silicate breccia.

Geology and Geochemistry of Noachian Bedrock and Alteration Events, Meridiani Planum, Mars:MER Opportunity Observations

1David W. Mittlefehldt et al. (>10)
Journal of Geophysical Research (Planets)(In Press) Link to Article []
1Mail code XI3, Astromaterials Research Office, NASA/Johnson Space Center, Houston, Texas, 77058 USA
Published by arrangement with John Wiley & Sons

We have used Mars Exploration Rover Opportunity data to investigate the origin and alteration of lithic types along the western rim of Noachian-aged Endeavour crater on Meridiani Planum. Two geologic units are identified along the rim: the Shoemaker and Matijevic formations. The Shoemaker formation consists of two types of polymict impact breccia: clast-rich with coarser clasts in upper units; clast-poor with smaller clasts in lower units. Comparisons terrestrial craters show that the lower units represent more distal ejecta from at least two earlier impacts, and the upper units are proximal ejecta from Endeavour crater. Both are mixtures of target rocks of basaltic composition with subtle compositional variations caused by differences in post-impact alteration. The Matijevic formation and lower Shoemaker units represent pre-Endeavour geology, which we equate with the regional Noachian subdued cratered unit. An alteration style unique to these rocks is formation of smectite and Si- and Al-rich vein-like structures crosscutting outcrops. Post-Endeavour alteration is dominated by sulfate formation. Rim-crossing fracture zones include regions of alteration that produced Mg-sulfates as a dominant phase, plausibly closely associated in time with the Endeavour impact. Calcium-sulfate vein formation occurred over extended time, including before the Endeavour impact and after the Endeavour rim had been substantially degraded, likely after deposition of the Burns formation that surrounds and embays the rim. Differences in Mg, Ca and Cl concentrations on rock surfaces and interiors indicate mobilization of salts by transient water that has occurred recently and may be ongoing.

The Planetary Terrestrial Analogues Library (PTAL) – An exclusive lithological selection of possible martian earth analogues

1Henning Dypvik et al. (>10)
Planetary and Space Science (in Press) Link to Article []
1Department of Geosciences and Department of Technology Systems, Univ. of Oslo, P.O. Box 1047, Blindern, NO 0316, Oslo, Norway

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