^1,2Zhan Zhou et al. (>10)
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JE009052]
¹Key Laboratory of Planetary Science and Frontier Technology, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
²University of Chinese Academy of Sciences, Beijing, China
Published by arrangement with John Wiley & Sons

The Moon has been highly shocked as evidenced by numerous impact craters on its surface. High-pressure minerals are expected to form during these shock events and can be used to unravel the pressure and temperature conditions for the shock events. However, high-pressure minerals are rarely reported in the lunar returned samples, yielding a discrepancy with the prediction. The lunar soils returned by the Chang’e-6 (CE6) mission from the South Pole-Aitken (SPA) basin provide new opportunities to investigate the shock metamorphism of the lunar samples and the shock events on the Moon. Here, we reported the discovery of coesite in a shock-induced melt pocket from a CE6 mare basalt, which could have experienced a shock event with a peak pressure of ∼24 GPa. The coesite exhibits two types of occurrences, a polycrystalline aggregate in the center and a ring along the margin of a silica clast. The coesite could have been formed by solid-state transformation followed by partial conversion to silica glass during decompression. The coesite has a higher survival temperature and a slower back-transformation rate than most other high-pressure minerals, which are favorable for its preservation under high-temperature conditions of lunar soils induced by impacts. These findings provide new insights for the preservation of coesite in natural shock events and indicate that more thermal-resistant high-pressure minerals could have been formed and preserved in lunar samples than previously thought, providing new targets for studying the shock events on the Moon.

¹Jessika L. Valenciano,¹Clive R. Neal,²Scott A. Eckley,³Charles K. Shearer, the ANGSA Science Team
Journal of Geophysical research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2024JE008580]
¹Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN, USA
²Amentum—JETS2, Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, TX, USA
³Institute of Meteoritics, University of New Mexico, Albuquerque, NM, USA
Published by arrangement with John Wiley & Sons

Double drive tubes 73002 (upper) and 73001 (lower) were collected during Apollo 17 from a landslide deposit at the base of the South Massif in the Taurus-Littrow valley. The drive tubes were opened for the first time as part of the Apollo Next Generation Sample Analysis (ANGSA) project, representing “new” samples from the Moon. Many lithic fragments (>1 mm in size) were extracted from the core during core dissection and preliminary examination (PE), including high-Ti mare basalt clasts. Those >4 mm fragments were three-dimensionally imaged using X-ray computed tomography (XCT). The crystal size distributions of ilmenite were measured in 10 high-Ti mare basalts and within the matrix of an impact melt breccia from drive tube 73002 using thin section “slices” from the 3D XCT scans. Residence times (of the crystals in the melt from which they grew) were estimated using experimental growth rates for each sample with all but 73002,2015 being relatively short (<1 year). Linear (constant) cooling rates were determined, expanding upon data already obtained from other Apollo 17 high-Ti basalts showing that these ANGSA basalt clasts had similar cooling histories to those previously studied. Comparison with ilmenite cooling rate experiments estimated cooling rates of <10°C/h for each clast.

^1,2,3David C. Fernandez-Remolar et al. (>10)
Journal of Geophysical Research (Planets) (in Press) Link to Article [https://doi.org/10.1029/2024JE008837]
¹State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Macau, PR China
²CNSA Macau Center for Space Exploration and Science, Macau, PR China
³University Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, Grenoble, France
Published by arrangement with John Wiley & Sons

Orbital remote sensing has shown that some regions of the ancient Martian crust contain hundreds of discrete terrains covered by chloride-rich evaporites. In terrestrial evaporitic systems, evaporite sequences typically begin with the deposition of carbonates, followed by sulfates, and finally chlorides, a depositional sequence that has not yet been found on Mars. Instead, sulfate deposits are always separated spatially and temporally from chlorides, suggesting two different depositional regimes. Here, we present a model driven by the Martian chlorine geochemical cycle that allows the formation of chlorides whilst simultaneously inhibiting sulfate and carbonate precipitation. In this model, the chlorides are produced under reducing and acidic conditions. Chloride deposition was driven by hydrothermal alteration of the Martian crust associated with faults, followed by precipitation from ascending saline solutions along the tectonic conduits. These processes occurred under a relatively thick and reducing atmosphere (1–0.1 bar). The crustal circulation of chloride-precipitating fluids may have been driven by tectonic suction and pumping processes. Parental brines from hydrothermal activity sourcing chloride might also have contributed to the sulfates found in Cross and Columbus craters of Terra Sirenum. Our study integrates orbital imaging, topography, and spectroscopy with geochemical modeling and terrestrial analogs. We propose that the Terra Sirenum chloride deposits derive from subsurface brines, with deposition driven using tectonic and hydrothermal processes. Under inferred reducing and anoxic conditions, chloride formed with minimal co-precipitation of sulfates and carbonates. Unlike isolated chloride deposits confined to topographic lows, the Terra Sirenum chlorides are associated with linear features interpreted as faults.

^1,2Joseph Razzell Hollis et al. (>10)
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2024JE008826]
¹Natural History Museum, London, UK
²NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
Published by arrangement with John Wiley & Sons

The NASA Mars 2020 mission Perseverance rover carries a piece of Martian meteorite Sayh al Uhaymir (SaU) 008 as part of the calibration payload for the SHERLOC science instrument. We report SHERLOC observations of the SaU 008 flight piece over the first 1,000 sols of the mission and compare them to measurements done prior to launch, showing consistent detection of the same deep-ultraviolet (DUV) Raman and fluorescence signatures in the same locations. Co-located X-ray fluorescence (XRF) and DUV mapping of a reference SaU 008 piece on Earth confirm that the meteorite is comprised of an igneous mineral matrix consistent with shergottite, rich in olivine, maskelynite, and Fe-Mg pyroxenes detectable by SHERLOC. Terrestrial weathering features consist of fractures and vugs filled with Ca-carbonate. Fluorescence mapping reveals two major signatures: (a) broad-spectrum fluorescence present throughout the igneous matrix but strongest in weathering features, attributed to organic material, and (b) narrow-band 340 nm fluorescence spatially associated with ∼48 ppm cerium in <100 μm Ca-phosphate grains. Raman revealed organic material in both the igneous matrix and terrestrial carbonate in the form of macromolecular carbon (MMC) with defect and graphitic bands at ∼1,380 and ∼1,600 cm−1 respectively. Raman band parameters suggest that MMC associated with terrestrial weathering is less thermally mature, most likely the result of chemical alteration after landing on Earth. This study serves as a demonstration of SHERLOC’s capabilities when supported by co-located XRF data from PIXL and suggests that SHERLOC can detect Ce in phosphate minerals at concentrations as low as 4 ppm.

^1,2,3Yuchun Wu,²Nicolas Mangold,^1,3,4Yang Liu,⁵John Carter,¹Xing Wu,^4,6Lu Pan,⁷Qian Huang,^1,2,3Chaolin Zhang,^1,3Keyi Li,⁶Yongliao Zou
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2025JE008951]
¹State Key Laboratory of Solar Activity and Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, China
²Laboratoire de Planétologie et Géosciences, Nantes Université, University Angers, Le Mans Université, CNRS, LPG UMR 6112, Nantes, France
³College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
⁴National Key Laboratory of Deep Space Exploration, Hefei, China
⁵Institut d’Astrophysique Spatiale, Université Paris-Saclay, CNRS, Orsay, France
⁶School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China
⁷Hubei Subsurface Multi-scale Imaging Key Laboratory, School of Geophysics and Geomatics, China University of Geosciences, Wuhan, China
Published by arrangement with John Wiley & Sons

Tyrrhena Terra, a region located in the cratered highlands between Hellas and Isidis Planitia on Mars, is distinguished by its extensive presence of hydrated minerals. Using 542 hyperspectral images from the Compact Reconnaissance Imaging Spectrometer for Mars, we detected 252 exposures of hydrated minerals. This region is characterized by a widespread distribution of Fe/Mg-smectites/vermiculites and chlorite, with additional detections of Al-phyllosilicates, zeolites, prehnite, hydrated silica, and carbonates. We classified the mineralogical detections in classes of impact crater diameters, locations in craters, and for those
20 km, their relative degradation stages. We found that craters
10 km display a lower mineral diversity than larger ones. In contrast, craters
20 km display a high mineral diversity, especially in central peaks, suggesting a strong influence of hydrothermal processes and deep excavation. Among this diameter range, fresh, young craters exhibit a much higher mineral diversity than degraded, old craters. Fe/Mg-phyllosilicates are dominant in the latter, as well as in sedimentary units of topographically low areas. These results indicate a long-term alteration cycle in the most ancient period, where the initial, diverse hydrated minerals—formed through exhumation and/or hydrothermal circulation within large impacts—were subsequently transformed by surface weathering and/or buried, dissolved, or eroded away by other post-impact processes, then transported and deposited in lowlands by fluvial erosion. Although Tyrrhena Terra is dominated by impact-related hydrated mineral detections, our study shows that the overprint of Noachian age weathering is visible within these detections.

¹Scott A. Eckley et al. (>10)
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2024JE008583]
¹Astromaterials Research and Exploration Science Division, Amentum – JETS2, NASA Johnson Space Center, Houston, TX, USA
Published by arrangement with John Wiley & Sons

Double drive tube 73001/2 was collected on the Light Mantle Deposit in the Taurus-Littrow Valley by Apollo 17 astronauts. It is a 4-cm diameter core that sampled up to 70 cm deep in a lunar landslide at the base of the North Massif. NASA kept these samples pristine and untouched in anticipation of advanced future analytical techniques, such as high-resolution X-ray computed tomography (XCT). Double drive tube 73001/2 was selected to be studied as part of the Apollo Next Generation Sample Analysis (ANGSA) program and was opened in November 2019 (73002) and February 2022 (73001). We discuss how XCT was utilized during the preliminary examination of these samples. This technique, which was unavailable the last time an Apollo drive tube was opened (1993), provides a three-dimensional (3-D) image of the interior of opaque objects. Prior to opening, high-resolution scans were collected of the full length of both cores, providing a novel 3-D archive of the intact lunar regolith. After opening, 352 > 4 mm particles were individually bagged and scanned, allowing for their lithological classification. We provide an example of the robustness of the individual particle data by analyzing ilmenite crystals (n = 350) in fourteen high-Ti basalt particles. Our results show that ilmenite generally has highly anisotropic shapes and can take on various external morphologies, indicating that 73001/2 likely sampled several lunar basalt flows. This paper illustrates the utility of XCT for curatorial and scientific purposes during ANGSA and demonstrates its value for future sample return missions.

^1,2Shuai-Yi Qu,^3,4Yu-Yan Sara Zhao,^5,6He Cui,⁶Shuai Zhang,⁷Xiuqin Yang,¹Honglei Lin,⁸Chao Qi,^4,9Xiongyao Li,^4,9Jianzhong Liu
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2024JE008688]
¹Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
²University of Chinese Academy of Sciences, Beijing, China
³Research Center for Planetary Science, College of Earth and Planetary Sciences, Chengdu University of Technology, Chengdu, China
⁴CAS Center for Excellence in Comparative Planetology, Hefei, China
⁵College of Life Sciences, Wuchang University of Technology, Wuhan, China
⁶Technical Center of Qingdao Customs, Qingdao, China
⁷State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry Chinese Academy of Sciences, Guiyang, China
⁸Center for High Pressure Science and Technology Advanced Research, Beijing, China
⁹Center for Lunar and Planetary Sciences, Institute of Geochemistry Chinese Academy of Sciences, Guiyang, China
Published by arrangement with John Wiley & Sons

Chlorine-bearing salts mixed with other minerals exposed to ultraviolet light participate in chlorine redox cycles on the Martian surface. Previous studies have shown that Fe^III sulfates can exclusively produce perchlorate by chloride photooxidation, but the mechanisms and effective scopes remain unclear. In this study, we investigated this perspective by conducting two main photochemical experiments using ultraviolet light 254 nm. Chloride oxidation experiments examined the effects of different Fe minerals (i.e., Fe^II sulfates, Fe^III sulfates, Fe^III chlorides, Fe^III nitrates, pyrrhotite, siderite and nontronite) and acidified non-Fe sulfates (Ca-, Mg-, Na-, and K- sulfates). Photocatalytic conversion experiments assessed the conversion products of perchlorate and chlorate in the presence of different sulfates (Fe^III, Ca, Mg, Na, and K). Our results showed that the ClO₃⁻/ClO₄⁻ molar ratios <<1 reported for Fe^III sulfates did not occur in any non-Fe sulfates, even after acidification by concentrated H₂SO₄. Other Fe salts, such as Fe^II sulfates, Fe^III nitrates, and Fe^III chlorides, also showed preferential ClO₄⁻ production, whereas pyrrhotite, siderite and nontronite produced more ClO₃⁻ than ClO₄⁻. Photocatalytic conversion experiments starting with NaClO₃ and NaClO₄ demonstrated that Fe^III can facilitate the direct NaClO₃-to-NaClO₄ conversion without producing Cl⁻ and inhibit the photolysis of NaClO₄. Our study highlights the unique role of hygroscopic Fe salts (both Fe^II and Fe^III) in the production and preservation of perchlorate. Mineral surfaces and water vapor may play essential roles in the chlorine redox cycle. The likely coexistence of perchlorate and Fe^III salts has important implications for liquid water on the present cold and arid Mars.

¹Atsushi Takenouchi,²Hirochika Sumino,^3,4Hideyuki Hayashi,⁵Takashi Mikouchi,⁶Martin Bizzarro
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.70055]
¹Kyoto University Museum, Kyoto University, Kyoto, Japan
²Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
³Department of Earth and Planetary Science, The University of Tokyo, Tokyo, Japan
⁴National Museum of Nature and Science, Ibaraki, Japan
⁵The University Museum, The University of Tokyo, Tokyo, Japan
⁶Center for Star and Planet Formation, University of Copenhagen, Copenhagen, Denmark
Published by arrangement with John Wiley & Sons

Angrites and eucrites are among the oldest basaltic rocks in the solar system. However, the shock histories of these meteorite groups differ markedly, as most angrites show little to no evidence of shock metamorphism. While some angrites exhibit weak wavy extinction in olivine, indicative of low-level shock, only two—Northwest Africa (NWA) 1670 and NWA 7203—are known to preserve significant shock features such as shock melt veins. To better constrain the shock history of angrites, we performed noble gas analyses on the rare shock-metamorphosed angrite NWA 7203 to determine its cosmic ray exposure and gas retention ages. Neon in NWA 7203 is entirely cosmogenic, and combined neon and argon data yield a cosmic ray exposure age of 22.7 ± 3.1 Ma (2σ). This age nominally differs from that of the other shocked angrite, NWA 1670, but is comparable to that of the unshocked angrite NWA 7812. NWA 7203 may have been ejected from a rubble pile-like asteroid composed of both shocked and unshocked materials. Two distinct 40Ar/39Ar apparent ages, 3.38 ± 0.10 Ga and 1.41 ± 0.11 Ga, were obtained, likely reflecting variable argon loss during a single impact-induced thermal event that occurred no earlier than 1.41 ± 0.11 Ga (2σ). This is the first report for the shock metamorphic age of an angrite. Our results reinforce the view that even shocked angrites lack clear evidence of a catastrophic disruption of their parent body (>100 km) hypothesized to have occurred in the early solar system. To resolve this conundrum, we propose that angrites may have experienced extensive melting during such an event, which suppressed or erased conventional shock features. If this impact occurred near the time of their crystallization (>4564 Ma), it may have been a “hot shock” event driven by heat from short-lived radionuclides. Such an event could have generated large volumes of shock melt, from which quenched angrites subsequently formed. We suggest that differentiated planetary bodies may have commonly undergone such early-stage disruption events during the formative epoch of the solar system.

^1,2Ben-Xun Su,¹Jing Wang,¹Qi-Qi Pan,¹Yan Xiao,¹Meng-Meng Cu
Journal of the Geological Society 182, Link to Article [https://doi.org/10.1144/jgs2024-19]
¹State Key Laboratory of Lithospheric and Environmental Coevolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
²College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China

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

¹Stephanie L. Halwa,¹Katherine H. Joy,¹Romain Tartèse,^1,2Samantha K. Bell
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.70057]
¹Department of Earth and Environmental Sciences, University of Manchester, Manchester, UK
²Stratum Reservoir AS, Sandnes, Norway
Published by arrangement with John Wiley & Sons

The lunar regolith contains a rich history of Solar System impact events and solar activity. Many future missions will land in the south polar region of the Moon, a heavily impact cratered highland terrain, similar to the Apollo 16 landing site. In preparation, it is important to understand regolith processes and the upper stratigraphy of the regolith in typical highlands regions. In this study, we used a nondestructive scanning electron microscope with the QEMSCAN software to analyze the mineralogical compositions and maturities of regolith samples from various depths within four Apollo 16 double drive tubes. Our results support previous analyses made using other techniques that there is a lack of stratigraphic correlation across the central and southern regions of the Apollo 16 landing site, where the cores show lateral and vertical heterogeneities. Our results also show that QEMSCAN is a powerful tool for rapid, quantitative assessment of regolith characteristics. Our findings can serve as an analog for south polar regolith, providing context for upcoming missions looking to sample the subsurface regolith in the south polar region.