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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¹T. Prabu,¹Kasinathan Muthukkumaran,²I. Venugopal,³S. Anbazhagan
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2023.105710]
¹Dept. of Civil Engineering, National Institute of Technology, Tiruchirappalli, 620015, Tamilnadu, India
²Department of Civil Engineering, M S Ramaiah Institute of Technology, Bangalore, Karnataka, India
³Faculty of Science, Director, Centre for Geoinformatics & Planetary Studies, Professor of Geology, Periyar University, Salem, 636011, Tamilnadu, India

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¹William R. HYDE,²Adam A. GARDE,²Nynke KEULEN,²Sebastian N. MALKKI,^3,4Steven J. JARET,⁵Tod WAIGHT,⁶Pierre BECK,⁷Iain McDONALD,¹Nicolaj K. LARSEN
Meteoritics & Planetary Science (in Press) Open Access Link to Article [doi: 10.1111/maps.13987]
¹Globe Institute, University of Copenhagen, Copenhagen K, Denmark
²Geological Survey of Denmark and Greenland, Copenhagen K, Denmark
³Department of Earth and Planetary Sciences, American Museum of Natural History, New York, New York, USA
⁴Department of Physical Sciences, Kingsborough Community College, City University of New York, Brooklyn, New York, USA
⁵Department of Geosciences and Natural Resource Management (Geology Section), University of Copenhagen, Copenhagen K,Denmark
⁶Universit ́e Grenoble Alpes, CNRS, IPAG, Grenoble, France
⁷School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK
Published by arrangement with John Wiley & Sons

Impact melt rocks formed during hypervelocity impact events are ideal forstudying impact structures. Here, we describe impact melt rock samples collected proximalto the 31 km wide 58 Ma Hiawatha impact structure, northwest Greenland, which iscompletely covered by the Greenland Ice Sheet. The melt rocks contain diagnostic shockindicators (e.g., planar deformation features [PDF] in quartz and shocked zircon) and formthree groups based on melt textures and chemistry: (i) hypocrystalline, (ii) glassy, and (iii)carbonate-based melt rocks. The exposed foreland directly in front of the structure consistsof metasedimentary successions and igneous plutons; however, the carbonate-basedimpactites indicate a mixed target sequence with a significant carbonate-rich component.Well-preserved organic material in some melt rocks indicates that North Greenland at thetime of impact was host to abundant organic material, likely a dense high-latitude temperateforest. Geochemical signatures of platinum-group elements in selected samples indicate anextraterrestrial component and support previous identification of a highly fractionated ironimpactor in glaciofluvial sand. Our results illustrate the possibility to study impact structureshidden beneath a thick ice sheet based on transported samples and this opens a new avenuefor identifying other potential impact craters in Greenland and Antarctica.

¹Nicolas D. GARRONI,¹Gordon R. OSINSKI
Meteoritics & Planetary Science (in Press) Open Access Link to Article [doi: 10.1111/maps.13993]
¹Department of Earth Sciences, University of Western Ontario, London, Ontario, Canada
Published by arrangement with John Wiley & Sons

Carbonates from the impact melt-bearing breccia in the 2016 IODP/ICDPExpedition 364 drill core at Site M0077 were systematically documented and characterizedpetrographically and geochemically. Calcite, the only carbonate mineral present, is abundantthroughout this deposit as five distinct varieties: (1) subangular carbonate clasts (Type A); (2)subround/irregular carbonate clasts with clay altered rims (Type B); (3) fine-crystalline matrixcalcite (Type C); (4) void-filling sparry calcite (Type D); and (5) microcrystalline carbonatewith flow textures (Type E). Quantitative geochemical analysis shows that calcite in allcarbonate varieties are low in elemental impurities (<2.0 cumulative wt% on average);however, relative concentrations of MgO and MnO vary, which provides distinction betweeneach variety: MgO is highest in calcite from Types A, B, and C carbonates (0.2–0.8 wt% onaverage); MnO is highest in calcite from Types B, C, and D carbonates (0.2–1.3 wt% onaverage); and calcite from Type E carbonate is most pure (<0.1 wt% on average MgO andMnO, cumulatively). Based on textural and geochemical variations between carbonate types,we interpret that some of the carbonate target rocks melted during impact and wereimmiscible within the silicate-dominated melt sheet prior to the resurgence of seawater. TypeB clasts were formed by molten fuel–coolant interaction, as the incoming seawater erodedthrough the melt sheet and encountered carbonate melt (Type E). Post-impact meteoric-dominated hydrothermal activity produced the Mn-elevated calcite from Type C and Dcarbonates, and altered the Type B clasts to be elevated in Mn and host a clay-rich rim.