¹S. De Angelis,¹M. Ferrari,¹M.C. De Sanctis,²E. Ammannito,¹A. Raponi,¹M. Ciarniello
Journal of Geophysical Research Planets (in Press) Link to Article [https://doi.org/10.1029/2020JE006696]
¹INAF‐IAPS, Via Fosso del Cavaliere 100, 00133 Rome, (Italy)
²ASI ‐ Agenzia Spaziale Italiana, Via del Politecnico snc, 00133 Rome, (Italy)
Published by arrangement with John Wiley & Sons

Ammonium phyllosilicates have been identified on the dwarf planet Ceres, thanks to infrared telescopic and orbital data from the Dawn mission, by means of the 3.06 μm spectral feature. Nevertheless, it is not known which ammonium‐bearing phyllosilicate species are present, nor the thermal processing they underwent throughout Ceres history. Identifying the NH4+‐hosting mineral species is important for deciphering Ceres’ surface mineralogy, which provides a link to its interior and putative different evolutionary pathways. Ammoniated species can have formed in the presence of water/ammonia‐rich fluids in different conditions in the interior of the planet; in case of an exogenous outer Solar System origin, they can have undergone heating at depth.

In this work, we study the visible‐infrared spectra of several NH4‐treated/untreated phyllosilicates in the range 0.35‐5 μm, acquired in vacuum and at temperatures between 298‐723K. Previously NH4‐phyllosilicates have been mostly studied at ambient condition, preventing the characterization of the NH4+ band at 3.06 μm, due to overlapping bands of water. With this new set of measurements, we investigate how the NH4‐phyllosilicates spectra are modified when the mineral’s water is lost, and which temperature is the limit for the releasing of NH4+. We present the first high temperatures/high vacuum 3‐μm reflectance spectra of ammonium phyllosilicates.

Our measurements indicate that Mg‐phyllosilicates are the best candidates for the ammonium‐bearing species. Moreover, the almost complete disappearing of NH4+ absorption feature at ∼3.06 μm for ammoniated phyllosilicates heated at the highest temperatures, indicates that such species on Ceres could not have experienced temperatures higher than 623K.

¹Paul G. Lucey,²Benjamin Greenhagen,³Kerri Donaldson Hanna,⁴Neil Bowles,¹Abigail Flom,⁵David A. Paige
Journal of Geophysical Research Planets (in Press) Link to Article [https://doi.org/10.1029/2020JE006777]
¹Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa
²The Johns Hopkins University Applied Physics Laboratory
³University of Central Florida
⁴Atmospheric, Oceanic and Planetary Physics, Clarendon Laboratory, Oxford University
⁵University of California at Los Angeles
Published by arrangement with John Wiley & Sons

Maps of plagioclase, olivine and pyroxene at 1 km resolution are derived from a combination of data from the Diviner Lunar Radiometer on the Lunar Reconnaissance Orbiter and the Kaguya Multiband Imager. The Diviner instrument features three infrared bands designed to characterize a spectral feature of lunar soils that is sensitive to the average silica polymerization of the surface called the Christiansen Feature, which is directly sensitive to the presence of plagioclase, the dominant lunar silicate. Existing global mineral maps based on near‐IR data largely infer the presence of plagioclase from the bright mineral’s effect on total reflectance, excepting in rare locations where the surface is nearly pure plagioclase and a weak feature in the plagioclase near‐IR spectrum can be relied upon. By integrating both wavelength regions we produced more robust estimates of the abundance of the three dominant minerals. In the process of this work, we also improved the removal of space weathering effects from Christiansen Feature maps, and showed that silica rich compositional anomalies could be reliably detected by decorrelating Christiansen Feature and FeO maps. New silica‐rich locations are reported as are the global abundances of the three major silicates.

^1,2Ryoga Maeda,¹Steven Goderis,²Vinciane Debaille,²Hamed Pourkhorsandi,²Geneviève Hublet,¹Philippe Claeys
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2021.05.005]
¹Analytical-, Environmental-, and Geo-Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, BE-1050 Brussels, Belgium
²Laboratoire G-Time, Université libre de Bruxelles, CP 160/02, 50, Av. F.D. Roosevelt, BE-1050, Brussels, Belgium
Copyright Elsevier

Long-lived radioactive isotope systematics, such as Sm-Nd and Lu-Hf, are useful tools as important chronometers and tracers for chemical differentiation processes. Even though Antarctic meteorites include rare meteorites such as ungrouped meteorites, the effects of Antarctic alteration on the Sm-Nd and Lu-Hf systems in chondrites have not yet been evaluated in detail. Moreover, the heterogeneity of Sm-Nd and Lu-Hf data in bulk chondrites prevents the determination of precise average Sm-Nd and Lu-Hf values (e.g., for individual chondrite groups). To examine the effects of Antarctic alteration and sample heterogeneity on the Sm-Nd and Lu-Hf isotope systematics, ten Antarctic H chondrites (HCs) and three HCs from hot deserts were characterized for their modal abundances, elemental abundances, and Sm-Nd and Lu-Hf isotopic compositions. Regardless of the classical weathering index for Antarctic meteorites and the normalized Rb abundance used as a chemical alteration indicator in this study, the modal and elemental abundances in Antarctic HCs appear to be in good agreement with those in non-Antarctic HCs. The Sm-Nd and Lu-Hf isotopic compositions of the characterized H chondrites fall within the range measured for both HC falls and for falls of other chondrite classes, except in the case of the most heavily altered samples. Consequently, the effects of Antarctic alteration processes on the Sm-Nd and Lu-Hf systematics in HCs appear to be limited, except in the case of Asuka 09516. The latter meteorite exhibits severe mineralogical and chemical alteration, with considerable losses of even the rare earth elements (REEs), which are considered relatively immobile. The 147Sm/144Nd, 143Nd/144Nd, 176Lu/177Hf, and 176Hf/177Hf of bulk HCs correlate with their P/Mg and Y/Mg. Furthermore, the Lu-Hf ratios correlate strongly with their P/Ca and Y/Ca as well as their P/Mg and Y/Mg. Thus, the distribution of the elements between constituent minerals in ordinary chondrites (OCs) may control the heterogeneity observed for the bulk Sm-Nd and Lu-Hf data. In this context, the weight ratio of Ca-phosphates to Ca-pyroxene, or at least that of Ca-phosphates to silicates, may be a key factor leading to the observed elemental and isotopic variations. This observation indicates that the nugget effect of Ca-phosphates in OCs as the result of insufficient homogenization or terrestrial alteration leads to the heterogeneities displayed by the Sm-Nd and Lu-Hf data. Moreover, it also indicates that the use of equilibrated OCs for the determination of Sm-Nd and Lu-Hf data is affected more by sample heterogeneity, especially with respect to Ca-phosphates, than is the case for unequilibrated OCs, based on the re-distribution of REEs during thermal metamorphism on their parent bodies. This study demonstrates that Antarctic meteorites commonly preserve their original Sm-Nd and Lu-Hf isotopic compositions as much as chondrite falls, although exceptions are possible in the case of severe alteration. Similar to previous studies, we recommend the use of unequilibrated chondrites, for which the re-distribution of REEs is less extensive, for the determination of well-constrained average Sm-Nd and Lu-Hf isotopic compositions for individual chondrite groups as well as their robust Chondritic Uniform Reservoir values.

¹Jean-Christophe Viennet,¹Sylvain Bernard,²Corentin Le Guillou,¹Violaine Sautter,³Brian Grégoire,¹Albert Jambon,¹Sylvain Pont,¹Olivier Beyssac,¹Brigitte Zanda,¹Roger Hewins,¹Laurent Remusat
Astrobiology (in Press) Link to Article [http://doi.org/10.1089/ast.2020.2345]
¹Muséum National d’Histoire Naturelle, Institut de Minéralogie, Physique des Matériaux et Cosmochimie, CNRS UMR 7590, Sorbonne Université, CNRS, F-75005 Paris, France
²Université Lille, CNRS, INRA, ENSCL, UMR 8207 – UMET – Unité Matériaux et Transformations, Lille, France.
³Centre National de la Recherche Scientifique (CNRS), Université de Poitiers, UMR 7285 IC2MP-Hydrasa, Poitiers, France.

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

¹J. Gregory Shellnutt,¹M.P. Manu Prasanth
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2021.114531]
¹National Taiwan Normal University, Department of Earth Sciences, 88 Tingzhou Road Section 4, Taipei 11677, Taiwan
Copyright Elsevier

Anorthosite is a plutonic igneous rock composed almost entirely of plagioclase feldspar. Telluric planets may initially develop a primary anorthositic crust before lithospheric recycling processes commence. Non-primary anorthosite forms as a consequence of accumulation of plagioclase that crystallizes from basaltic or primitive mafic/ultramafic magma. Here we show that fractional crystallization modeling of parental magma compositions similar to basalt identified on Venus can yield plagioclase with anorthite contents typical of non-primary anorthosites of Earth. Using terrestrial anorthosite typology, we conclude that analogues of Archean megacrystic anorthosite, layered mafic intrusion anorthosite, and anorthosite inclusions are likely to be present within the crust of Venus. Proterozoic massif-type anorthosite, if present, would likely be restricted to the highland terranes of Ishtar Terra and Ovda Regio whereas oceanic anorthosites are unlikely to be present. Furthermore, our results indicate that the leucite-rich cumulate rock known as italite may also exist within the Venusian crust.

¹Filip Košek,¹Adam Culka,²Anastasia Rousaki,^2,3Peter Vandenabeele,¹Jan Jehlička
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2021.114533]
¹Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic
²Raman Spectroscopy Research Group, Department of Chemistry, Ghent University, Krijgslaan 281, S12, 9000 Gent, Belgium
³Archaeometry Research Group, Department of Archaeology, Ghent University, Sint-Pietersnieuwstraat 35, B-9000 Ghent, Belgium
Copyright Elsevier

Organic molecules are currently believed to be abundant in space, but the possible biogenic origin, or the mere existence, on some planetary surfaces, Mars specifically, is a pending question. Reliable methods of detection are required to answer this question unambiguously and Raman spectroscopy has already been suggested for this task years ago. With exploration missions aiming to Mars on the horizon, collecting experience and building databases will have crucial importance investigations of analytical data obtained through Raman instrumentation onboard of rovers in the frame of Mars 2020 and other forthcoming missions. This work focuses on the evaluation of some portable Raman systems coupled to different excitation lasers (532, 785, 1064 nm and a dual laser system with sequentially shifted excitation SSE) for the detection of various organic molecules, with emphasis on non-complicated measure protocol and observation of fluorescence emission when a different wavelength is used. By using a simple statistical approach, we demonstrate a generally good readability of the obtained spectra for most of the investigated organics regardless the excitation sources and instruments used. A varying level of fluorescence emission was encountered, resulting in higher background for the 532 nm and 785 nm instrumentation while 1064 nm and SSE spectrometers provided almost fluorescence-free spectra. These results illustrate how the relatively simple miniaturized Raman spectrometers can provide fast and unambiguous identification of various organic compounds which are of great importance in the current and future planetology and/or exobiology missions.

¹Daniele Fulvio,¹Leonardo Fuks,¹Maron Yaima,¹Cires Perez,¹Tahir Tommaso,¹Del Rosso
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2021.114532]
¹Department of Physics, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marques de São Vicente, 22451- 900 Rio de Janeiro, Brazil
Copyright Elsevier

The term “space weathering” refers to processes that include changes in the physical, chemical, mineralogical, and spectral properties of the surface of asteroids, comets, and some planets and their satellites, such as the bombardment by micrometeorites, solar wind ions, and cosmic rays. In this study, we focus on micrometeorite impacts, which may be the primary contributor to the annual mass flow of material that reaches the surface of such bodies. Studying the processes and effects associated with micrometeorite impacts is fundamental for understanding the evolution of the solar system and its components. From an experimental point of view, it is typically assumed that micrometeorite impacts may be simulated by ns -pulsed lasers and, indeed, many experimental studies have been performed based on such assumption. These studies have the common main goal to understand how micrometeorite impacts may change the physical -chemical and spectral properties of the bombarded surfaces. However, here we perform the first experimental study dedicated to the morphological characterization of the impact craters created by ns -pulsed laser ablation, in order to determine how well ns -pulsed lasers simulate the crater morphology of natural micrometeorite impacts. For this purpose, the laser ablation technique was applied to three different silicates: feldspar, quartz, and jadeite. For each of these minerals, two ablation scenarios have been considered: in air and in water. The craters formed by ns -pulsed laser ablation were characterized, from the morphological point of view, using a profilometer. Using this data we estimated the depth:diameter ratio of each crater. The comparison with literature data shows that the simple craters formed by ns -pulsed laser ablation closely resemble craters formed by natural micrometeorite impacts. In other words, from a morphological point of view, ns -pulsed laser ablation is appropriate for the simulation of micrometeorite impacts. We additionally verified that the value of the depth:diameter ratio does not depend, within errors, on the total number of laser pulses or the repetition frequency, at least within the ranges covered in these experiments: i) between 1 and 1200 laser pulses and ii) between 1 and 10 Hz.

¹Shaunna M. Morrison,¹Robert M. Hazen
American Mineralogist 106, 730–761 Link to Article [http://www.minsocam.org/msa/ammin/toc/2021/Abstracts/AM106P0730.pdf]
¹Earth and Planets Laboratory, Carnegie Institution for Science, 5251 Broad Branch Road NW, Washington, D.C. 20015, U.S.A
Copyright: The Mineralogical Society of America

The fourth installment of the evolutionary system of mineralogy considers two stages of planetesimal mineralogy that occurred early in the history of the solar nebula, commencing by 4.566 Ga and lasting for at least 5 million years: (1) primary igneous minerals derived from planetesimal melting and differentiation into core, mantle, and basaltic components and (2) impact mineralization resulting in shock-induced deformation, brecciation, melting, and high-pressure phase transformations.
We tabulate 90 igneous differentiated asteroidal minerals, including the earliest known occurrences
of minerals with Ba, Cl, Cu, F, and V as essential elements, as well as the first appearances of numerous
phosphates, quartz, zircon, and amphibole group minerals. We also record 40 minerals formed through
high-pressure impact alteration, commencing with the period of asteroid accretion and differentiation.
These stages of mineral evolution thus mark the first time that high pressures, both static and dynamic,
played a significant role in mineral paragenesis.

¹S.Anbazhagan et al. (>10)
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2021.114511]

¹Centre for Geoinformatics and Planetary Studies, Periyar University, Salem 636 011, Tamil Nadu, India
Copyright Elsevier

Lunar Regolith Simulants are imperative materials required for In-Situ Resource Utilization (ISRU), simulating physical and chemical properties of the lunar terrain, testing landers and mobility of rovers, and calibration of payloads and sensors. The available simulants do not represent all the lunar terrain environments and are insufficient to conduct the above experiments. The Indian Space Research Organization (ISRO) took up necessary steps to launch the Chandrayaan-2 mission after successfully completing the Chandrayaan-1 mission. The Chandrayaan-2 mission included an orbiter, a lander and a rover. ISRO’s UR Rao Satellite Centre (URSC) has decided to have a dedicated Lunar Terrain Testing Facility (LTTF) at Bengaluru. URSC has planned for a bulk quantity of lunar soil simulant similar to Lunar highland composition. The task was assigned to the Centre for Geoinformatics and Planetary Studies, Department of Geology at Periyar University in southern India. The bulk quantity of Lunar soil stimulant was produced from the anorthosite rocks collected from the Sittampundi Anorthosite Complex (SAC) exposed in the southern part of India. We report the merit of the source area, geological setting, chemistry, mineral phase, soil characteristics, and grain size distribution of simulant material. The anorthosite rocks collected from SAC have a higher abundance of calcic plagioclase, and the proportion of major oxides is mostly equivalent to lunar highland anorthosite. ISRO’s lunar soil simulant LSS-ISAC-1 has similarity with the Lunar highland regolith in the majority and has fidelity to represent the highland terrain. The testing facility, LTTF, was used for testing the soft landing of the lander and mobility of the rover of the Chandrayaan-2 mission.

¹Eugene G. Grosch,²Janice L. Bishop,³Christian Mielke,⁴Alessandro Maturilli,⁴Jörn Helbert
American Mineralogist 106, 672–684 Link to Article [http://www.minsocam.org/MSA/AmMin/TOC/2021/Abstracts/AM106P0672.pdf]
¹Geology Department, Rhodes University, Grahamstown/Makhanda 6140, South Africa 2
²Carl Sagan Center, SETI Institute and NASA-Ames Research Center, Mountain View, California 94043, U.S.A. 3
³GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam 4
⁴Institute for Planetary Research, DLR, Rutherfordstrasse 2, 12489, Berlin-Adlershof, Germany
Copyright: The Mineralogical Society of America

Characterization of terrestrial analog sites is critical for detection and determination of clay mineralogy in remote sensing studies of Mars aimed at geological, hydrological, and potentially biological
investigations. In this study, we investigate a suite of hydrothermally altered early Archean rocks from
the Barberton greenstone belt (BGB) of South Africa as potential petrological, mineralogical, and
spectral analogs to hydrothermally altered metabasalts and mafic-ultramafic intrusions in the martian
subsurface and impact craters. We present the first spectral imaging measurements on exceptionally
well-preserved early Archean mafic-ultramafic rocks from the BGB, with the aim of studying their
clay mineralogy and spectral signatures. Multiple spectral analyses were conducted on different
sample textures (rock powders, crushed rocks, and rock slabs) appropriate for Mars rover and remote
sensing exploration. Visible/near-infrared (VNIR) and mid-IR reflectance spectra were acquired on
particulate samples, while VNIR spectral imaging data were collected on rock slabs. Mid-IR emission
spectra were measured for the rock slabs and grains. Spectral features are compared from these different spectral techniques to identify the minerals present in the samples and compare macroscale vs.
microscale detections. The measured spectra reveal absorption bands that correspond to clay mineralogy of the serpentine and chlorite mineral groups, consistent with petrographic observations, as well
as magnetite, olivine, quartz, feldspar, and Al-phyllosilicate. The spectral data acquired in this study
expand the reference spectra data set for remote sensing studies. The implications of this study are that
rocks from early Archean greenstone belts, such as those of the BGB, serve as potential clay-bearing
petrological analogs for hydrothermal environments on Mars.