¹Peter Mc Ardle,¹Rhian H. Jones,^2,3,4Luke Daly,¹Romain Tartèse,⁵Patricia L. Clay,⁵Brian O’Driscoll,¹Ray Burgess,⁶William Smith,⁶Colin How,¹Lewis Hughes
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.70073]
¹Department of Earth and Environmental Sciences, University of Manchester, Manchester, UK
²School of Geographical and Earth Sciences, University of Glasgow, Glasgow, UK
³Department of Materials, University of Oxford, Oxford, UK
⁴Australian Centre for Microscopy & Microanalysis, University of Sydney, Camperdown, New South Wales, Australia
⁵Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Ontario, Canada
⁶School of Physics and Astronomy, University of Glasgow, Glasgow, UK
Published by arrangement with John Wiley & Sons

Enstatite chondrites formed under extremely reducing conditions in the protoplanetary disk. They are derived from two or more parent bodies, EH and EL, and both EH and EL groups contain petrologic type 3–6 samples. The rare lithophile- and halogen-bearing sulfide, djerfisherite, occurs in low abundance in enstatite chondrites, most frequently in the EH3 chondrites. In some EH3 chondrites, but not in EL chondrites, djerfisherite is associated with a fine-grained mineral assemblage, termed the “Qingzhen Reaction,” which has previously been interpreted as an alteration product of djerfisherite. The Qingzhen Reaction is notable as perhaps the only record of fluid-mediated alteration on the EH parent body. In this study, we undertook a high-resolution chemical and mineralogical analysis of the Qingzhen Reaction and its djerfisherite host, in order to determine its composition, relationship to djerfisherite and its formation environment. We show that the Qingzhen Reaction is an alteration product of djerfisherite, predominantly comprised of porous troilite with remnant djerfisherite. Trace quantities of halite and (likely) sphalerite are also present. We suggest that the Qingzhen Reaction formed by the interaction of an anhydrous fluid with djerfisherite on the EH parent body.

¹G. Lopez-Reyes et al. (>10)
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2025JE008943]
¹ERICA Research Group and LaDIS. Universidad de Valladolid (Spain), Valladolid, Spain
Published by arrangement with John Wiley & Sons

The Mars 2020 Perseverance rover introduced Raman spectroscopy to in situ planetary exploration for the first time when it landed in Jezero crater on Mars in February 2021. The SuperCam instrument onboard Perseverance is a multi-analytical tool capable of acquiring time-resolved Raman data from Martian targets at standoff distances of a few meters. This is a particularly challenging task due to the operational constraints, the harsh conditions on the Martian surface, and especially the very fine-grained nature of the Martian soil. To address these challenges, the SuperCam Raman team has invested significant effort into optimizing both the acquisition and post-processing of Raman data collected on Mars, as detailed in this work. Additionally, this paper reviews and discusses the detections made by SuperCam Raman during the first 1,000 sols (almost 3 Earth years) of the Mars 2020 mission. During this period, SuperCam Raman data provided key insights into the mineralogy of Jezero throughout the Crater, Delta, and Margin Campaigns. Key detections include olivine, carbonates, perchlorates, and sulfates (such as anhydrite), identified in both abraded patches and natural surfaces. The high specificity of Raman spectroscopy enables the unequivocal identification of these minerals, allowing for rapid and direct interpretation of Jezero’s mineralogy, especially when combined with other techniques from SuperCam or others on the rover. Furthermore, this paper compiles the spectra acquired from the SuperCam Calibration Target samples on Mars, including studies on the degradation of the Ertalyte (PET), an organic polymer sample and analyses of diamond, apatite, and other reference materials.

¹Weronika Ofierska, ¹Max W. Schmidt, ¹Christian Liebske, ¹Paolo A. Sossi
Earth and Planetary Science Letters 673, 119691 (in Press) Open Access Link to Article [https://doi.org/10.1016/j.epsl.2025.119691]
¹Department of Earth and Planetary Science, ETH, Zürich, Switzerland
Copyright Elsevier

Owing to the incompatibility of K, rare-earth elements (REE) and P in silicate minerals relative to melt, the KREEP component, found on the near-side of the Moon, is thought to have formed through protracted crystallisation of the Lunar Magma Ocean (LMO). Our fractional crystallisation experiments simulate the final stages of LMO crystallisation, from plagioclase onset to the last eutectic melt remnants. Results show the LMO liquid to remain saturated in olivine ± orthopyroxene ± Cr-spinel up to 74 % solidification (PCS), transitioning to plagioclase+clinopyroxene (cpx) from 1200 °C (74 PCS) to 1120 °C (88 PCS). The plagioclase+cpx+quartz cotectic is reached at 1080 °C (92.3 PCS), with liquid immiscibility and a crystal assemblage of plagioclase+augite+Ti-spinel+ilmenite+quartz occurring at 1030 °C (98.8 PCS), until nearly complete crystallization is reached at 1000 °C (99.5 PCS). Mineral/melt (plagioclase, pigeonite, high-Ca cpx) and melt/melt partition coefficients for K, REE, P, Zr, Hf, Nb, Th, and U were determined. They are used to model melt evolution to 99.5 PCS, showing that fractional crystallisation alone replicates KREEP’s REE profile and the above trace elements, yet, distinct Lu/Hf (and U/Pb) ratios suggest additional processes. Assuming a finite oxygen budget in the LMO and incompatible behaviour of Fe3+, the Eu anomaly of KREEP is best reproduced by a model in which oxygen fugacity (
) evolves from one log unit below to 1.5 log units above the iron-wustite buffer (IW-1 to IW+1.5) from 0 PCS to 99.4 PCS. Minor dacitic melt separation (1–5 % of the melt remaining at 1030 °C) sequestering K from REE+P is consistent with but unnecessary for KREEP formation; nevertheless, a second-stage partial re-melting of these dacites could match observed FeO and incompatible element abundances of lunar granites.

¹Francisca S. Paiva,^2,3Silvio Sinibaldi
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2025JE009132]
¹KU Leuven, Leuven, Belgium
²European Space Agency, Noordwijk, The Netherlands
³The Open University, Milton Keynes, UK
Published by arrangement with John Wiley & Sons

Recent detections of water ice in the permanently shadowed regions (PSRs) at the lunar poles have reignited scientific and commercial interest in the exploration of Earth’s closest neighbor. The frigid temperatures in PSRs operate as cold traps for volatiles and may represent large reservoirs of materials, including water ice and prebiotic organic molecules, delivered to the Earth-Moon system through meteorite or cometary impacts over billions of years (Crawford, 2006, https://doi.org/10.1017/s1473550406002990). Nonetheless, scientific investigations of lunar poles rely on the absence of extraneous volatiles introduced during lunar missions, which may hide pristine evidence of such materials. In the present work, we develop a numerical model for the transport of spacecraft exhaust volatiles on the Moon. Using ESA’s Argonaut missions as a case study, featuring a descent at the lunar South Pole, we apply this model to assess the potential impact of organic contamination from lunar landers on scientific research of lunar ice chemistry by tracing the migration of methane
molecules to the PSRs. Our simulation results suggest that approximately half of the released
molecules end up trapped in PSRs at the South or North poles within 7 lunar days, with their distribution dictated by interactions with the lunar surface. Moreover, cross-contamination between poles proves significant, as approximately
of molecules become trapped in the north polar region, despite only a limited fraction of these falling within the latitude limit of
defined for Category IIb in COSPAR Planetary Protection Policy.

¹Angelina Minocha,¹Ryan C. Ogliore,^2,3Paul K. Carpenter,^2,3Christopher Yen,^2,3Bradley L. Jolliff
Journal of Geophysical Research (in Press)(in Press) Open Access Link to Article [https://doi.org/10.1029/2024JE008614]
¹Physics Department, University of Central Florida, St. Louis, MO, USA
²McDonnell Center for the Space Sciences, Washington University in St. Louis, St. Louis, MO, USA
³Department of Earth, Environmental, and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, USA
Published by arrangement with John Wiley & Sons

We have developed the Quantitative Microanalysis Explorer, or QME-Tool, a web-based platform for visualization of large imaging data sets and interrogation of quantitative elemental maps acquired by electron microprobes. Using a combination of open-source JavaScript libraries and custom scripts, the QME-Tool can be used to quickly identify interesting mineral and lithologic phases in a sample by comparing backscattered-electron (BSE), optical, and X-ray images, extract quantitative chemical composition in regions from electron-probe microanalysis (EPMA) stage maps, and easily share data and sample locations with colleagues. We have used the QME-Tool to study regolith contained in 12 petrographic thin sections of the Apollo 17 double-drive tube 73001/2 as part of the Apollo Next Generation Sample Analysis (ANGSA) Program. As an example of the utility of the QME-Tool, we have characterized a ∼500 × 750 μm basaltic lithic clast located in the 73002,6016 polished thin section, using a BSE image, quantitative EPMA stage maps, optical reflected light, and transmitted light in both plane-polarized and crossed-polarized images. In addition to non-destructive quantitative composition extraction, we examine phase chemistry and compute a bulk composition for the clast as well as a supervised classification (using pre-defined mineral clusters) according to its mineralogy. The data show that in its major element composition, the clast is essentially similar to ilmenite basalt 70017. This connection is used to argue that the high-Ti basalt clasts in the drive tube originated from impacts into the valley floor and help reconstruct the emplacement mechanism of the light mantle deposit.

^1,2Miguel Arribas Tiemblo,¹Pedro Rayo,¹María-Paz Martín-Redondo,¹Felipe Gómez
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2025JE009070]
¹Centro de Astrobiología (CAB), CSIC-INTA, Madrid, Spain
²Universidad de Alcalá de Henares (UAH), Madrid, Spain
Published by arrangement with John Wiley & Sons

Amino acids are an extremely heterogeneous group of biomolecules essential for life on Earth. Their biosignatures are expected to be easily degraded on the Martian surface as the absence of a thick atmosphere and a magnetosphere leads to most of the solar radiation directly reaching its surface. To determine the preservation of amino acids in the Martian regolith, and their detectability, we exposed protein-sourced and free amino acids to UV-B radiation. This was done while in contact with different particle size ranges of two Martian regolith simulants. Bulk analysis through High Performance Liquid Chromatography (HPLC) showed that UV-B radiation led to little damage across all samples, mainly targeting sensitive amino acids like tyrosine, histidine, tryptophan and methionine. The two Martian simulants were divided into five particle size ranges. Smaller particles (<0.045 mm) led to higher recoveries than bigger ones (>0.500 mm), likely through their high specific surface area. Raman spectroscopy offered localized surface information, which HPLC was unable to. One of the simulants (MMS-2) is rich in iron oxides like hematite, which likely prevented any detection by absorbing the excitation wavelength of the laser. Irradiation also led to widespread loss of signal of all amino acids. Overall, the limitations of both techniques were compensated by each another, which allowed for the precise characterization of the chemical alterations suffered by amino acids in these conditions.

^1,2Erbin Shi,²Alian Wang,³I-Ming Chou,¹Zongcheng Ling
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2024JE008867]
¹Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai, China
²Department of Earth & Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, St. Louis, MO, USA
³CAS Key Laboratory of Experimental Study Under Deep-Sea Extreme Conditions, Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China
Published by arrangement with John Wiley & Sons

Ferric sulfate minerals have been identified by orbital and landed missions at multiple locations on Mars and are the most common minerals in the Acid Mine Drainage (AMD) system on Earth. The occurrences and the speciation of ferric sulfates are very sensitive to variations in environmental conditions, such as temperature (T), relative humidity (RH%), redox potential (Eh), and potential of hydrogen ions (pH). In this study, two phase boundaries among kornelite, paracoquimbite, and ferricopiapite were experimentally derived in T–RH% space, using the well-established humidity buffer technique. The phase transformation and phase identification during experiments were determined by the gravimetric measurements and laser Raman spectroscopy, respectively. The two new phase boundaries clearly defined the edges of the stable fields of paracoquimbite that were ambiguously determined in a previous study. From the experimental data, we derived the entropy, enthalpy, and Gibbs free energy of the two reactions, and calculated the enthalpy changes and Gibbs free energy changes for each water of crystallization (either enter or escape from the structure) of these hydrous ferric sulfates. When compared with the same parameters of hydrous metal (Fe3+, Fe2+, Cu2+, Mg2+, Ni2+, Zn2+, Co2+, Mn2+, Cd2+, and Na+) sulfates derived by previous hydration/dehydration studies, we found a strong consistency, especially the Gibbs free energy changes. This finding implies the very consistent energetic barriers for the hydration/dehydration of those sulfates, post their first hydration/dehydration, regardless of their difference in cation and crystal structure.

^1,2Yun Chen et al. (>10)
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2025JE009293]
¹National Key Laboratory of Aerospace Mechanism, Harbin Institute of Technology, Harbin, China
²Center for Lunar and Planetary Sciences, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
Published by arrangement with John Wiley & Sons

Micrometeoroid impacts play a key role in space weathering during the evolution of lunar regolith. The micro-cratering morphology and material transformation of common lunar phases are effective ways to understand the interaction between the space environment and matter, but there are few systematic studies. Micro-analysis is conducted on the microcraters in the Chang’e-5 lunar soil to evaluate the microscale impact effects. Here, our study reveals the different morphological characteristics and internal microstructure of microcraters across five typical components (pyroxene, olivine, plagioclase, ilmenite, and glass). The impact effects include planar defects like dislocation slip, amorphization, and the formation of np-Fe0 and vesicles. Key parameters, including the microcrater depth to diameter ratio and microcrater diameter to impactor diameter ratio, are calculated to quantify microcrater morphology. The formation process of microcraters is reproduced with the smoothed-particle hydrodynamic method. The results suggest that the microcraters retain transient characteristics, likely from low-speed micrometeoroids or secondary impact events. These microscale impacts exhibit lower intensity compared to microcraters from Apollo samples, indicating weak space weathering processes on young basalt. The exploratory work tries to provide a comprehensive summary of low-speed impact-induced microcraters in lunar soil and outlines the theoretical frameworks for understanding microscale impact processes.

¹Takaharu Saito, ¹Kengo Iwamoto, ²Shigekazu Yoneda, ³Seung-Gu Lee, ¹Hiroshi Hidaka
Geochimica et Cosmochimica Acta (in Press) Open Access Link to Article [https://doi.org/10.1016/j.gca.2025.11.013]
¹Department of Earth and Planetary Sciences, Nagoya University, Nagoya 464-8601, Japan
²Department of Science and Engineering, National Museum of Nature and Science, Tsukuba 305-0005, Japan
³Geology and Space Division, Korea Institute of Geoscience and Mineral Resources, Daejeon 34132, Republic of Korea
Copyright Elsevier

Neutron-capture reactions are fundamental processes driving isotopic variations among cosmic-ray-irradiated planetary materials. The energy spectra of neutrons interacting with these planetary materials provide insights into their cosmic-ray exposure conditions and enable quantitative estimates of neutron-induced isotopic shifts in elements of interest. In this study, we measured Yb and Hf isotopic compositions of Apollo15 deep drill core samples, which provide information on higher-energy neutrons compared with conventional neutron indicators of Sm, Gd, and Er. Furthermore, we developed a calculation method to reconstruct a neutron spectrum from isotopic shifts in Sm, Gd, Er, Yb and Hf. Applying the method to Apollo 15 samples revealed significant neutron spectrum variations in the lunar subsurface. The observed epithermal neutron spectrum variations likely reflect depth dependence of energy moderation processes of neutrons. A neutron spectrum at the lunar surface estimated from our data is enriched in lower-energy epithermal neutrons compared with those calculated from numerical calculations in previous studies. The depth-dependent spectrum variations observed in the Apollo 15 samples possibly affect correction calculations of neutron-capture effects for nuclides strongly influenced by epithermal neutrons, such as ¹⁷⁶Hf. This is important in the context of accurate interpretation of radiometric and isotopic studies of lunar samples, which often record significantly high neutron fluences due to long-time cosmic-ray exposure on the lunar surface.

¹Eloise E. Matthews,^1,2Auriol S. P. Rae,³Thomas Kenkmann,⁴Nicholas E. Timms,⁴Aaron J. Cavosie,¹Marian B. Holness
Meteoritica & Planetray Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.70070]
¹Department of Earth Sciences, University of Cambridge, Cambridge, UK
²School of GeoSciences, University of Edinburgh, Edinburgh, UK
³Institute of Earth and Environmental Sciences—Geology, Albert-Ludwigs Universität Freiburg, Freiburg, Germany
⁴School of Earth and Planetary Sciences, Curtin University, Bentley, Western Australia, Australia
Published by arrangement with John Wiley & Sons

The majority of planetary impacts occur at oblique angles. Impact structures on Earth are commonly eroded or buried, rendering the identification of the direction and angle of impact—using methods such as asymmetries in ejecta distribution, surface topographic expression, central uplift structure, and geophysical anomalies—challenging. In this study, we investigate the potential of spatial asymmetries in shock metamorphism intensity to act as a quantitative constraint on the direction and angle of impact at the Gosses Bluff structure in Northern Territory, Australia. We measured the frequency of specific orientations of planar deformation features in quartz from nine samples around the central uplift and compared the spatial asymmetries in observed peak shock conditions with predictions from new three-dimensional numerical impact simulations of the formation of the Gosses Bluff structure. This comparison indicates formation by an impact along an approximately N→S trajectory at an angle of 52° ± 10°. The direction agrees with previous independent identification of structural asymmetry at the crater, although an attempt to constrain the impact angle has not been previously conducted. Alongside a trend of an increase in shock pressure recorded by down-range target rocks, we also observe a marked increase in shock metamorphism in the cross-range direction at Gosses Bluff. We attribute this pattern to the movement of faults in the central uplift during crater modification, displacing and dissecting the originally smooth distribution of shock metamorphism. This study provides new guidance for identifying and quantifying oblique impacts in the rock record, which is applicable to a large range of impact angles and crater sizes.