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.

¹S.T.Port,¹V.F.Chevrier,²E.Kohler
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2019.113432]
¹University of Arkansas, Center for Space and Planetary Sciences, Fayetteville, AR 72701, United States
²NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States
Copyright Elsevier

The source of the unusually high radar reflectivity signal found on the highlands of Venus is hypothesized to be caused by a mineral with a high dielectric constant. We propose that this source is a combination of tellurium, sulfur, and bismuth. All three elements are commonly outgassed in terrestrial eruption plumes and thus are likely to be found on Venus. To test our hypothesis, we used a Venus simulation chamber and studied the stability of various tellurium, bismuth, and sulfur mixtures at Venus temperatures and pressures and in atmospheres of CO2, 100 ppm SO2 in CO2, or 100 ppm COS in CO2. When mixed together bismuth, tellurium, and sulfur phases preferentially formed tetradymite (Bi2Te2S). The remaining minerals that formed in each experiment strongly depended on the initial mixture. For instance the Bi2S3/Bi2Te3 mixture experiments resulted in the original minerals as well as BiTe at hotter temperatures, meanwhile the Bi/Te/S mixture produced Bi2S3 and occasionally Bi2Te3, Bi(S,Te), and Bi4(S,Te)3 depending on the temperature/pressure. There is evidence that COS, but not SO2, affected the stability of some minerals. Due to the presence of these elements in volcanic gases we propose that they can be present in the highlands and can, at least in part, account for the high radar reflectivity signal on the highlands.

^1,2Keyron Hickman-Lewis,¹Frédéric Foucher,³Steven Pelletier,⁴Fabio Messori,¹Frances Westall
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2019.104743]
¹CNRS Centre de Biophysique Moléculaire, Rue Charles Sadron, 45071, Orléans, France
²Dipartimento di Scienze Biologiche, Geologiche e Ambientali (BiGeA), Università di Bologna, Via Zamboni, 67, I 40126, Bologna, Italy
³Université François Rabelais de Tours, Tours, France
⁴Università Degli Studi di Modena e Reggio Emilia, Modena, Italy

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