¹O.Beyssac et al. (>10)
Journal of Geophysical Research (Planets) (in Press) Link to Article [https://doi.org/10.1029/2022JE007638]
¹Institut de Minéralogie, CNRS, Sorbonne Université, Muséum National d’Histoire Naturelle, de Physique des Matériaux et de Cosmochimie, 75005 Paris, France
Published by arrangement with John Wiley & Sons

Séítah is the stratigraphically lowest formation visited by Perseverance in the Jezero crater floor. We present the data obtained by SuperCam: texture by imagery, chemistry by LIBS, and mineralogy by VISIR and Raman spectroscopy. The Séítah formation consists of igneous, weakly altered, rocks dominated by millimeter-size grains of olivine with the presence of low-Ca and high-Ca pyroxenes, and other primary minerals (e.g., plagioclase, Cr-Fe-Ti oxides, phosphates). Along a ∼140 m long section in Séítah, SuperCam analyses showed evidence of geochemical and mineralogical variations, from the contact with the overlying Máaz formation, going deeper in the formation. Bulk rock and olivine Mg#, grain size, olivine content increase gradually further from the contact. Along the section, olivine Mg# are not in equilibrium with the bulk rock Mg#, indicating local olivine accumulation. These observations are consistent with Séítah being the deep ultramafic member of a cumulate series derived from the fractional crystallization and slow cooling of the parent magma at depth. Possible magmatic processes and exhumation mechanisms of Séítah are discussed. Séítah rocks show some affinity with some rocks at Gusev crater, and with some martian meteorites suggesting that such rocks are not rare on the surface of Mars. Séítah is part of the Nili Fossae regional olivine-carbonate unit observed from orbit. Future exploration of Perseverance on the rim and outside of the crater will help determine if the observations from the crater floor can be extrapolated to the whole unit, or if this unit is composed of distinct sub-units with various origins.

¹Vivian Z. Sun et al. (>10)
Journal of Geophysical Research (Planets) (in Press) Open Access Link to Article [https://doi.org/10.1029/2022JE007613]
¹Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
Published by arrangement with John Wiley & Sons

The Mars 2020 Perseverance rover landed in Jezero crater on February 18, 2021. After a 100-sol period of commissioning and the Ingenuity Helicopter technology demonstration, Perseverance began its first science campaign to explore the enigmatic Jezero crater floor, whose igneous or sedimentary origins have been much debated in the scientific community. This paper describes the campaign plan developed to explore the crater floor’s Máaz and Séítah formations and summarizes the results of the campaign between sols 100-379. By the end of the campaign, Perseverance had traversed more than 5 km, created seven abrasion patches, and sealed nine samples and a witness tube. Analysis of remote and proximity science observations show that the Máaz and Séítah formations are igneous in origin and composed of five and two geologic members, respectively. The Séítah formation represents the olivine-rich cumulate formed from differentiation of a slowly cooling melt or magma body, and the Máaz formation likely represents a separate series of lava flows emplaced after Séítah. The Máaz and Séítah rocks also preserve evidence of multiple episodes of aqueous alteration in secondary minerals like carbonate, Fe/Mg phyllosilicates, sulfates, and perchlorate, and surficial coatings. Post-emplacement processes tilted the rocks near the Máaz-Séítah contact and substantial erosion modified the crater floor rocks to their present-day expressions. Results from this crater floor campaign, including those obtained upon return of the collected samples, will help to build the geologic history of events that occurred in Jezero crater and provide time constraints on the formation of the Jezero delta.

MSR Campaign Science Group (MCSG) et al. (>10)
Meteoritics & Planetary Science (in Press) Open Access link to Article [doi: 10.1111/maps.139811]
Published by arrangement with John Wiley & Sons

The Mars 2020/Mars Sample Return (MSR) Sample Depot Science CommunityWorkshop was held on September 28 and 30, 2022, to assess the Scientifically-ReturnWorthy (SRW) value of the full collection of samples acquired by the rover Perseverance atJezero Crater, and of a proposed subset of samples to be left as a First Depot at a location within Jezero Crater called Three Forks. The primary outcome of the workshop was thatthe community is in consensus on the following statement: The proposed set of ten sampletubes that includes seven rock samples, one regolith sample, one atmospheric sample, andone witness tube constitutes a SRW collection that: (1) represents the diversity of theexplored region around the landing site, (2) covers partially or fully, in a balanced way, allof the International MSR Objectives and Samples Team scientific objectives that areapplicable to Jezero Crater, and (3) the analyses of samples in this First Depot on Earthwould be of fundamental importance, providing a substantial improvement in ourunderstanding of Mars. At the conclusion of the meeting, there was overall communitysupport for forming the First Depot as described at the workshop and placing it at theThree Forks site. The community also recognized that the diversity of the Rover Cache (thesample collection that remains on the rover after placing the First Depot) will significantlyimprove with the samples that are planned to be obtained in the future by the Perseverancerover and that the Rover Cache is the primary target for MSR to return to Earth.

¹Y. O. CHETVERIKOV,^1,2V. F. EZHOV,^3,4M. S. GLUKHOV,^5,6E. M. IVANKOVA,²A. S. LOSHACHENKO,²V. D. KALGANOV,^2,7O. V. YAKUBOVICH
Meteoritics & Planetary Science (in Press) Link to Article [doi: 10.1111/maps.13991]
¹Petersburg Nuclear Physics Institute named by B. P. Konstantinov of National Research Center “Kurchatov Institute”,Gatchina, Russia
²Saint Petersburg State University, St. Petersburg, Russia
³Kazan Federal University, Kazan, Russia
⁴Zavaritsky Institute of Geology and Geochemistry, Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Russia
⁵Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
⁶Kirov Military Medical Academy, St. Petersburg, Russia7Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, St. Petersburg, Russia
Published by arrangement with John Wiley & Sons

Dust particles obtained by filtering fresh snow collected from May to September2017 in the vicinity of Vostok station in Antarctica were examined using a scanning electronmicroscope. The collection of dust particles contains 197 spherules ranging from 0.5 to 117μmin diameter, the most abundant ones (n=188) by far being iron oxide spherules. Analyses ofmeteorological and human activity data suggest an extraterrestrial origin of most of thespherical particles. The particle size distribution histogram showed a smooth increase in theirnumber with decreasing size and a dramatic drop at sizes smaller than 3μm. The number ofspherical particles has an uneven distribution over time, with an intense peak in July 27–28,2017 which correlates by dates with the peak of the Southern Delta Aquariids meteor shower.The size distribution of the particles collected during the same period indicates the presenceof a mechanism that accelerates their fall to the Earth. We propose that they are effectivecenters of condensation of ice crystals in stratospheric clouds. Our data indicate thatcollection of micrometeorites with sizes of several microns from the fresh snow is possible,opening a new way for sampling micrometeorites, including separate meteor showers.

^1,2,3,4Marie J.B. Henderson,⁴Briony H.N. Horgan,⁵Samuel J. Lawrence,⁶Julie D. Stopar,⁶Lisa R. Gaddis
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115628]
¹Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
²Center for Space Sciences and Technology, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
³Center for Research and Exploration in Space Science and Technology, NASA/GSFC, Greenbelt, MD 20771, USA
⁴Purdue University, West Lafayette, IN 47907, USA
⁵NASA Johnson Space Center, Houston, TX 77058, USA
⁶Lunar and Planetary Institute, Houston, TX 77058, USA
Copyright Elsevier

The Marius Hills Volcanic Complex exhibits the highest concentration of extrusive volcanic landforms on the Moon, in the form of both domes and cones. The interpretive advancements made in this investigation result from improved spectral resolution and analysis techniques. Moon Mineralogy Mapper (M3) spectral analysis shows that the rounded landforms in MHVC exhibit spectra consistent with glass, confirming a cinder cone with an explosive volcanic origin. The presence of scoria-like glass-rich pyroclasts that should be distinct from the glass beads collected during Apollo. This research provides evidence that spectroscopy can identify volcanic landforms when visible images of the morphology are inconclusive, which is essential for future exploration of volcanic terrains. The likely concurrent eruption of the domes and cones with the differences in the mineralogy of the resulting edifices (e.g., presence of glass) add supporting evidence to the hypothesis that extrinsic properties (e.g., ascent rate), not changes in magma composition (e.g., amount of volatiles), led to the different volcanic morphologies. Combining the morphology and the spectral data, we hypothesize that the magma evolution of the region was long-lived and with distinct early edifice-forming and later mare-forming episodes. The long-lived volcanism recorded in multiple volcanic units within close proximity in MHVC would be ideal for future exploration and eventual sample return.

¹Dorian Thomassin,¹Laurette Piani,¹Johan Villeneuve,²Marie-Camille Caumon,¹Nordine Bouden,¹Yves Marrocchi
Earth and Planetary Science Letters 616, 118225 Link to Article [https://doi.org/10.1016/j.epsl.2023.118225]
¹Université de Lorraine, CNRS, CRPG, UMR 7358, Nancy, France
²Université de Lorraine, GeoRessources, UMR 7359, Nancy, France
Copyright Elsevier

Due to their numerous isotopic similarities to terrestrial rocks, enstatite chondrites (ECs) are commonly proposed as Earth’s main building blocks. Although ECs contain sufficient H concentrations to account for the mass of Earth’s oceans, the physicochemical process(es) behind their H incorporation remain under constrained. Here, we combined secondary ion mass spectrometry analyses of volatile contents (H, C, F, Cl, S) and H isotopic compositions with Raman spectroscopy analyses of H speciation in the glassy mesostases of EC chondrules. EC chondrule mesostases (68–830 wt. ppm H) contain much more H than chondrule silicates (5–25 wt. ppm) and are characterized by H isotopic compositions of δD = −109 ± 27‰. Hydrogen and sulfur contents are positively correlated in EC chondrule mesostases, and we commonly observed well-resolved Raman peaks at 2580 cm−1, corresponding to HS− or H2S bonding. These results illustrate that the high H abundances in EC chondrule mesostases do not result from terrestrial contamination or secondary asteroidal processes, nor were their high volatile contents inherited from chondrule precursors. Instead, they were established at high temperature during chondrule formation via interactions between Fe-poor melts and S-rich gas under extremely reducing conditions. Our data confirm that ECs contain sufficient primordial hydrogen to explain the terrestrial water budget, and likely contributed important amounts of other volatile elements such as carbon, which was fundamental to the formation of life.

¹Tutukov A.V.,¹Chupina N.V.,¹Vereshchagin S.V.
Astronomy Reports 66, 1028-1042 Link to Article [DOI 10.1134/S1063772922110191]
¹Institute of Astronomy, Russian Academy of Sciences, Moscow, 119017, Russian Federation

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¹Takeshima, Yuko,^1,2Hyodo, Hironobu,³Tsujimori, Tatsuki,⁴Gouzu, Chitaro,
^4,5,6Itaya, Tetsumaru
Minerals 13, 31 Open Access Link to Article [DOI 10.3390/min13010031]
¹Graduate School of Science, Okayama University of Science, Okayama, 700-0005, Japan
²Institute of Frontier Science and Technology, Okayama University of Science, Okayama, 700-0005, Japan
³Center for Northeast Asian Studies, Tohoku University, Aoba, Sendai, 980-8576, Japan
⁴Hiruzen Institute for Geology & Chronology, 2-12 Nakashima, Naka-ku, Okayama, 703-8252, Japan
⁵Japan Geochronology Network, 2-12 Nakashima, Naka-ku, Okayama, 703-8252, Japan
⁶Institute of GeoHistory, Japan Geochronology Network, 1599 Susai, Akaiwa, 701-2503, Japan

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¹Ming Ma,¹Chen Jingran,^2,3Shengbo Chen,²Peng Lu,¹Chao Sun,¹Chenghao Han
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115645]
¹School of Surveying and Exploration Engineering, Jilin Jianzhu University, Changchun 130118, China
²School of Geo-Exploration Science and Techniques, Jilin University, Changchun 130026, China
³Center for Excellence in Comparative Planetology, Chinese Academy of Sciences, Hefei 230026, China
Copyright Elsevier

Topographic correction for lunar optical and thermal infrared remote sensing images is a challenging task. Although geometrical, photometrical or albedo-dependent correction methods have been used in an attempt to eliminate topographic effects in the initial lunar reflectance and emissivity images, these methods did not perform well on lunar steep slopes, large crater interiors or walls. In this paper, a novel neural network topographic correction (NNTC) model that was trained based on the relationships between flat (< 0.1° slope angle) and rugged pixels with similar Kaguya FeO abundance and optical maturity parameters (OMATs) (relative ratio < 0.1%) was applied to the Lunar Reconnaissance Orbiter (LRO) Diviner standard Christiansen feature (CF) image. The topographic correction accuracy is 0.03 μm, and no outliers are produced. Visual comparisons with the previous topographic corrected reflectance and emissivity images indicate that the topographic effects on various slope and aspect pixels were effectively corrected. The excavated anorthosite materials in the highland crater (such as the Jackson, Giordano Bruno and Tycho) interiors, surroundings, ejecta, and ray deposits have very similar NNTC CF values. The crater structures in maria or cryptomaria are identified more clearly. In addition, the NNTC method has the potential to be a universal topographic correction method for lunar optical and thermal infrared images, and it provides reliable data sources and a new method for space weathering correction.

^1,2 Stefanescu, Doru M.
International Journal of Metalcasting (in Press) Link to Article [DOI 10.1007/s40962-023-00971-5]
¹The University of Alabama, Tuscaloosa, AL, United States
²The Ohio State University, Columbus, OH, United States

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