^1,2Jemma Davidson,²Devin L.Schrader,¹Conel M.O’D.Alexander,¹Larry R.Nittler,³Roxane Bowden
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2019.09.033]
¹Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, Washington DC, 20015-1305, USA
²Center for Meteorite Studies, School of Earth and Space Exploration, Arizona State University, 781 East Terrace Road, Tempe, AZ 85287-6004, USA
³Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, Washington DC, 20015-1305, USA
Copyright Elsevier

We re-examine the Renazzo-like (CR) chondrite metamorphic trend based on Cr₂O₃ contents of FeO-rich olivine, indicating that it is only appropriate to use such analyses to identify endmembers (i.e., those that have experienced either no detectable heating or significant heating). As such Miller Range (MIL) 090657 appears to have experienced very minimal (if any) thermal processing and is one of the most pristine CR chondrites analyzed to date, while Graves Nunataks 06100 is the most shock-heated CR chondrite studied.

On the basis of bulk H-C-N isotopic compositions, MIL 090657 appears to be of petrological type 2.7. We also report the H-C-N isotopic compositions of extracted insoluble organic matter, in situ chemical compositional data, presolar grain abundances, and a petrologic description of MIL 090657. As a minimally altered CR chondrite of relatively high mass (133.1 g), MIL 090657 provides an invaluable opportunity to perform coordinated, often destructive, analyses on pristine CR chondrite material.

By combining a number of petrographic characteristics (Cr₂O₃-content of ferroan olivine, Co/Ni ratios of Fe,Ni metal, ratios of Fe# in chondrule olivine and low-Ca pyroxene, and the presence of excess silica in chondrule plagioclase) with bulk isotopic compositions, we demonstrate their utility as indicators for determining the relative pristinity/heating of low petrographic (type 1 to 3) chondrites.

^1,3C.J. Renggli,¹A.B. Palm,¹P.L. King,²P. Guagliardo
Journal of Geophysical Research, Planets (in Press) Link to Article [https://doi.org/10.1029/2019JE006045]
¹Research School of Earth Sciences, The Australian National University, Canberra ACT 2601, Australia
²Centre for Microscopy, Characterization and Analysis, University of Western Australia, PerthWA 6009, Australia
³Institute for Mineralogy, University of Münster, Münster,48149, Germany
Published by arrangement with John Wiley & Sons

Basalts are ubiquitous in volcanic systems on several planetary bodies, including the Earth, Mars, Venus and Jupiter’s moon Io, and are commonly associated with sulfur dioxide (SO₂) degassing. We present the results of an experimental study of reactions between SO₂ and basaltic glasses. We examined Fe‐free basalt, and Fe‐bearing tholeiitic and alkali basalts with a range of Fe³⁺/Fe_total (0.05 to 0.79) that encompass the oxygen fugacities proposed for most terrestrial planetary bodies. Tholeiitic and alkali basalts were exposed to SO₂ at 600, 700 and 800 °C for 1 h and 24 h. Surface coatings formed on the reacted basalts; these contain CaSO₄, MgSO₄, Na₂SO₄, Na₂Ca(SO₄)₂, Fe₂O₃, Fe₃O₄, Fe‐Ti‐(Al)‐oxides and TiO₂. Additionally, the SO₂‐basalt reaction drives nucleation of crystalline phases in the substrate to form pyroxenes and possible Fe‐oxides. A silica‐rich layer forms between the substrate and sulfate coatings. More oxidized basalts may readily react with SO₂ to form coatings dominated by large Ca‐sulfate and oxide grains. In less oxidized basalts (NNO‐1.5 to NNO‐5), reactions with SO₂ will form thin, fine‐grained aggregates of sulfates; such materials are less readily detected by spectroscopy and spectrometry techniques. In contrast, in very reduced basalts (lower than NNO‐5), typical of the Moon and Mercury, SO₂ is typically a negligible component in the magmatic gas, and sulfides are more likely.

¹H.M.Sargeant,¹F.A.J.Abernethy,¹S.J.Barber,¹I.P.Wright,¹M.Anand,¹S.Sheridan,¹A.Morse
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2019.104751]
¹The Open University, United Kingdom

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¹Stefan Linke,²Lisa Windisch,³Nico Kueter,⁴Jan Egil Wanvik,¹Anna Voss,¹Enrico Stoll,²Carsten Schilde,²Arno Kwade
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2019.104747]
¹Institute of Space Systems, TU Braunschweig, Hermann-Blenk-Straße 23, 38108 Brauschweig, Germany
²Institute for Particle Technology, TU Braunschweig, Volkmaroder Straße 5, 38104 Braunschweig, Germany
³Institute of Geochemistry and Petrology, Federal Institute of Technology (ETH) Zurich, Clausiusstrasse 25, 8092, Zurich, Switzerland
⁴Geological Survey of Norway, Leiv Eiriksons vei 39, 7040 Trondheim, Norway

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^1,2Sheng Gou,^1,2,3 Kaichang Di,^1,3Zongyu Yue,¹Zhaoqin Liu,⁴Zhiping He,⁴Rui Xu,⁵Honglei Lin,^1,2Bin Liu,¹Man Peng,¹Wenhui Wan,¹Yexin Wang,⁶Jianzhong Liu
Earth and Planetary Science Letters 528, 115829 Link to Article [https://doi.org/10.1016/j.epsl.2019.115829]
¹State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China
²State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Macau, China
³CAS Center for Excellence in Comparative Planetology, Hefei 230026, China
⁴Key Laboratory of Space Active Opto-Electronics Technology, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083, China
⁵Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
⁶Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
Copyright Elsevier

China’s Chang’e-4 spacecraft achieved the first ever soft-landing within the South Pole-Aitken (SPA) basin on the farside of the Moon. The Chang’e-4 rover, named Yutu-2, made in-situ spectral observations on lunar regolith and a rock fragment at 11 locations during a nominal three-month mission period. The lunar regolith has a relative high olivine/pyroxene ratio, with the pyroxene being chiefly Mg-rich Low-Ca pyroxene (LCP). The rock fragment has a similar Mg-rich composition to that of the regolith. According to the surrounding topographic and geologic context, though originating from the lower base of a differentiated melt pool cannot be excluded here, the rover observed regolith and rock fragment are very likely to be lunar mantle materials excavated from nearby Finsen crater.

^1,2Toni Schulz,¹Florian Sackl,¹ Elisabeth Fragner,³Ambre Luguet,^3,4David Van Acken,⁵Begosew Abate,⁶Dimitri D.Badjukov,^1,7Christian Koeberl
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2019.08.045]
¹Department of Lithospheric Research, University Vienna, Althanstrasse 14, 1090 Vienna, Austria
²Institut für Geologie und Mineralogie, Universität zu Köln, Zülpicher Strasse 49b, 50674 Köln, Germany
³Steinmann-Institut für Geologie, Mineralogie and Paläontologie, Universität Bonn, Poppelsdorfer Schloss, 53115 Bonn, Germany
⁴Irish Centre for Research in Applied Geosciences (iCRAG), UCD School of Earth Sciences, University College Dublin, Belfield, Dublin 4, Ireland
⁵Orbit Ethiopia PLC, Addis Ababa, Ethiopia
⁶Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Science, 19 Kosygin Str., 119991 Moscow, Russia
⁷Natural History Museum, Burgring 7, 1010 Vienna, Austria
Copyright Elsevier

The Zhamanshin impact structure, which is about 1 Myr old, has a diameter of 14-km and is situated in the semi-arid region of Kazakhstan (48°24’N,60°58’E). It has a heterogeneous suite of target rocks, including predominantly crustal lithologies (e.g., clays and siltstones) with minor ultramafics.
Zhamanshin is known for its unique association of impact glasses, including basic and acidic varieties of zhamanshinites and (tektite-like and few aerodynamically-shaped) irghizites. The origin of both of these impact glasses has long been debated, which is complicated by incomplete sampling of target lithologies at the Zhamanshin site and a limited number of isotopic analyses. However, such studies are a prerequisite for a comprehensive discussion of the mechanisms that formed the unique association of different impact glasses in one impact event.
We present major- and trace element contents, as well as combined Sr-Nd isotope data for target rocks and impact glasses from the Zhamanshin impact structure. These data, for the first time, include Paleogene clays and siltstones from a core drilled in the vicinity of the crater and cutting through all major lithologies. The core samples represent an important source lithology for the impactites from the Zhamanshin area.
Mixing calculations, based on the geochemical data and Sr-Nd isotope signatures, indicate that irghizites and Si-rich zhamanshinites can be produced from variously homogenized mixtures of mainly clays and siltstones with minor additions of ultrabasic rocks. Based on highly siderophile element (HSE) and Os isotope data (including the first analyses of the clay and siltstone lithologies) we calculated a hypothetical Os composition of the irghizite precursor, allowing us to approximate a chondritic admixture to the irghizites of roughly 1% of a chondritic component. This confirms previous suggestions about the amount of extraterrestrial components. A new HSE and Os isotope dataset for five zhamanshinites reveals, on average, crust-like HSE concentrations and Os isotope compositions confirming earlier suggestions of a lack of meteoritic admixtures to these impact glasses.

^1,2Ling, ¹Le Qiao,¹Changqing Liu,¹Haijun Cao,¹Xiangyu Bi,¹Xuejin Lu,¹ Jiang Zhang,¹Xiaohui Fu,^1,3Bo Li,⁴Jianzhong Liu
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2019.104741]
¹Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai, 264209, China
²Center for Excellence in Comparative Planetology, Chinese Academy of Sciences, Hefei, 230026, China
³College of Geoexploration Science and Technology, Jilin University, Changchun, 130026, China
⁴Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China

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¹Anicia Arredondo,^2,3Vania Lorenzi,⁴Noemi Pinilla-Alonso,¹Humberto Campins,¹Andrew Malfavon,^3,5Juliade León,^5,6DavidMorat
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2019.113427]
¹Physics Department, University of Central Florida, P.O. Box 162385, Orlando, FL 32816, USA
²Fundación Galileo Galilei – INAF, La Palma (TF), Spain
³Instituto de Astrofísica de Canarias, Tenerife, Spain
⁴Florida Space Institute, University of Central Florida, Orlando, FL 32816, USA
⁵Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain
⁶Observatório Nacional, Coordenação de Astronomia e Astrofísica, 20921-400 Rio de Janeiro, Brazil
Copyright Elsevier

The PRIMitive Asteroid Spectroscopic Survey (PRIMASS) aims to characterize primitive asteroids throughout the asteroid belt in the visible and near-infrared (NIR). There are eight primitive families in the inner main belt: Polana-Eulalia, Erigone, Sulamitis, Clarissa, Chaldaea, Klio, Svea and Chimaera. PRIMASS has already characterized all 8 families in the visible, and the Polana-Eulalia complex in the NIR. Results of our previous work show that low inclination inner belt family asteroids fall into at least two distinct compositional groups: Polana-like (anhydrous and spectrally homogeneous) or Erigone-like (hydrated and spectrally diverse). In the visible, the Klio family is spectrally diverse and 23% of the objects show evidence of hydration, but it is not Erigone-like.

We observed 21 objects in the Kilo family using the NASA InfraRed Telescope Facility (IRTF) and the Telescopio Nazionale Galileo (TNG) between January 2017 and March 2019. Our survey shows that the Klio family is spectrally homogeneous in the NIR, i.e., the heterogeneity seen in the visible does not extend to the NIR. The Klio family NIR spectra have mostly convex shapes and have red slopes (average slope 1.052 ± 0.425%/1000 Å normalized at 1.0 μm). The average spectra of both families we have studied in the NIR (Polana-Eulalia and Klio) differ slightly in spectral shape and slope, consistent with space weathering effects, but not conclusively so. Based on our NIR spectral comparisons, the Klio family cannot be ruled out as a possible source for two near-Earth asteroids: (101955) Bennu and (162173) Ryugu.

¹Rubio-Ordóñez, A.,¹García-Moreno, O.,²Terente, L.M.R.,³García-Guinea, J.,³Tormo, L.
Minerals 9, 417 Link to Article [DOI: 10.3390/min9070417]
¹Departamento de Geología, Universidad de Oviedo, C/Jesús Arias de Velasco s/n, Oviedo, 33005, Spain
²Museo de Geología, Universidad de Oviedo, C/Jesús Arias de Velasco s/n, Oviedo, 33005, Spain
³Departamento de Geología, Museo Nacional de Ciencias Naturales (MNCN-CSIC), C/José Gutiérrez Abascal 2, Madrid, 28006, Spain

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^1,2Xiaohui Fu,¹Liangchen Jia,³Alian Wang,¹Haijun Cao,^1,2 Zongcheng Ling,¹Changqing Liu,¹Erbin Shi,¹Zhongchen Wu,¹Bo Li,¹Jiang Zhang
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2019.113435]
¹Shandong Provincial Key Laboratory of Optical Astronomy & Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai, China
²CAS Center for Excellence in Comparative Planetology, Hefei, China
³Department of Earth and Planetary Sciences, McDonnell Center for Space Sciences, Washington University, St. Louis, MO, USA
Copyright Elsevier

Akaganeite has been found in Yellowknife Bay mudstones of the Gale crater by the Chemistry and Mineralogy X-ray diffraction instrument (CheMin) aboard the Curiosity rover. This phase has also been discovered in limited locations on Mars by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard the Mars Reconnaissance Orbiter. Akaganeite has also been proposed as a precursor candidate of hematite on Mars. To better constrain the stability and occurrence of akaganeite on Martian surfaces, structural and spectral modifications of akaganeite introduced by heating and desiccation were systematically investigated. We found that the phase transformation from akaganeite to hematite starts at 245 °C, which is accompanied by the removal of chloride in tunnels. We propose that geological activities (e.g., impact and volcanism on Mars) could heat the surrounding area and cause the transformation of akaganeite into hematite in Martian rocks and surface materials. Relative humidity (RH) variations result in water combination and overtone absorptions band strength changes. The CRISM spectrum of akaganeite detected in the Robert Sharp crater shows relatively weak 1.39 μm band compared to that of desiccated akaganeite under simulated Martian environments, indicating that akaganeite found on Mars could be highly desiccated. The water adsorption of akaganeite occurred when exposed to ambient laboratory conditions (RH ~65%). This suggests the water adsorption and desorption of akaganeite on Mars correspond to RH changes in a diurnal cycle.