¹Fei Su et al. (>10)
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2024JE008495]
¹Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
Published by arrangement with John Wiley & Sons

The Chang’e-5 landing site provides an important window into the Moon’s late Eratosthenian period of volcanism at ∼2 Ga. Clarifying the Moon’s history of volcanic activity using radioisotopic dating assists investigations of the evolution of the lunar surface as well as the Moon’s internal dynamics. Recent chronological investigations of Chang’e-5 basalts produced ages spanning ∼100 Ma, thereby inhibiting interpretation of the duration of volcanism recorded in the returned samples. We used microcomputed tomography and Back-Scatter Electron imaging to characterize the structure and morphology of nine Chang’e-5 basalt clasts. Several basalt clasts lack shock features and are interpreted to have not been significantly thermally disturbed. 40Ar/39Ar incremental heating produced well defined plateaus for four sub-split samples that give a weighted mean age of 2,021 ± 17 Ma (2σ). These are among the youngest mare basalts to be dated thus far by the 40Ar/39Ar method and, when combined with most of the published Pb-Pb ages for Chang’e-5 basalts, define a single episode of mare volcanism at ∼2,021 Ma.

¹Zhongtian Zhang,¹Peter E. Driscoll
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2024JE008671]
¹Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
Published by arrangement with John Wiley & Sons

Some melted and differentiated planetesimals, such as the parent bodies of angrites and howardite-eucrite-diogenite meteorites, are severely depleted in moderately volatile elements (MVEs). The origins of these depletions are critical for understanding early solar system evolution but remain topics of debate. Numerous previous studies have invoked evaporation from magma oceans as a potential mechanism for producing these depletions, yet this process is poorly explored. In this study, we examine the efficiency of MVE loss from planetesimal magma oceans. Upon heating from short-lived A⁢l26, internal magma oceans can develop beneath insulating crusts. The magma oceans may be exposed to the surface by collisional disruption of the crusts, but would be rapidly cooled by the cold environments. The exposed surface would be quenched to solid/glass; even if the quenched skin can be recycled by convection such that the magma ocean can be continuously resurfaced, only a small portion of the surface can remain molten. In the convection boundary layer, “vertical” advection is suppressed, energy and element transports toward the surface occur via thermal and chemical diffusion (if MVEs do not exsolve as bubbles). As chemical diffusivity is much smaller than thermal diffusivity, MVE transport is much less efficient than heat transport, and MVE loss during magma ocean cooling is likely minimal (≲1% the total inventory). Therefore, MVE depletions may not be easily explained by evaporation from A⁢l26-heated planetesimal magma oceans.

¹Chengxiang Yin,^1,2Xiaohui Fu,¹Haijun Cao,¹Xuejin Lu,¹Jian Chen,¹Jiang Zhang,^1,2Zongcheng Ling,³Xiaochao Che
Journal of Geophysical Research (Planets) (in Press) Link to Article [https://doi.org/10.1029/2024JE008733]
¹Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Technology, Institute of Space Sciences, Shandong University, Weihai, China
²CAS Center for Excellence in Comparative Planetology, Chinese Academy of Sciences, Hefei, China
³Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, China
Published by arrangement with John Wiley & Sons

Submicroscopic metallic iron particles (SMFe) are unique components of lunar soil produced during long-term exposure on the Moon’s surface. They can significantly alter the optical properties of lunar soil and this alteration is crucial for the interpretation of remote sensing data. The origin and formation of SMFe remain a subject of controversy, with multiple competing mechanisms coexisting. The newly returned Chang’e-5 (CE-5) samples provide a new opportunity to elucidate the formation of SMFe. Here, we conducted a systematical study on the morphology and chemical characteristics of metal globules in CE-5 impact melt splash. A total of 30,630 metal globules were identified with an average diameter of 222.87 nm. Most of them are nearly/perfectly spherical, but the others are irregular in shape. Three types of irregular metal globules have been found: Spindle type, deformation type, and coalescence type. Spindle and deformation types were formed under the influence of local thermal disequilibrium and/or differences in wettability, while the coalescence type reflects the growth of metal globules driven by the Oswald ripening. A series of metal globules at different coalescence stages were found, providing conclusive petrographic evidence for the long-term hypothesis of SMFe growth (e.g., Pieters & Noble, 2016, https://doi.org/10.1002/2016je005128). Geochemical analysis shows that meteoritic Fe-Ni metals (like iron meteorite) made a significant contribution to the formation of metal globules. This further indicates the contribution of exotic meteoroid materials to the CE-5 lunar soil.

¹P.Beck et al. (>10)
Earth and Planetary Science Letters 656, 119256 Open Access Link to Article [https://doi.org/10.1016/j.epsl.2025.119256]
¹Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
Copyright Elsevier

On Earth, silica-rich phases from opal to quartz are important indicators and tracers of geological processes. Hydrated silica, such as opal, is a particularly good matrix for the preservation of molecular and macroscopic biosignatures. Cherts, a type of silica-dominated rocks, provide a unique archive of ancient terrestrial life while quartz is the emblematic mineral of the Earth’s continental crust. On Mars, hydrated silica has been detected in several locations based on remote sensing and rover-based studies. In the present article we report on the detection of cobbles made of hydrated silica (opal or chalcedony), as well as well-crystallized quartz. These detections were made with the SuperCam instrument onboard Perseverance (Mars 2020 mission), using a combination of LIBS, infrared and Raman spectroscopy. Quartz-dominated stones are detected unambiguously for the first time on the Martian surface, and based on grain size and crystallinity are proposed to be of hydrothermal origin. Although these rocks were all found as float, we propose that these detections are part of a common hydrothermal system, and represent different depths / temperatures of precipitation. This attests that hydrothermal processes were active in and around Jezero crater, possibly triggered by the Jezero crater-forming impact. These silica-rich rocks, in particular opaline silica, are very promising targets for sampling and return to Earth given their high biosignature preservation potential.

¹Fang, Linru,¹Moynier, Frédéric,¹Chaussidon, Marc,¹Limare, Angela,¹Makhatadze, Georgy V.,²Villeneuve, Johan
Science Advances 11, eadp9381 Open Access Link to Article [DOI 10.1126/sciadv.adp9381]
¹Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, Paris, 75005, France
²Université de Lorraine, CNRS, CRPG, UMR7358, Nancy, F-54000, France

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^1,5Stude, Joan,¹Aufmhoff, Heinfried,¹Schlager, Hans,^1,2Rapp, Markus,¹Baumann, Carsten,⁴Arnold, Frank,³Strelnikov, Boris
Atmospheric Chemistry and Physics 25, 383-396 Open Access Link to Article [DOI 10.5194/acp-25-383-2025]
¹German Aerospace Center (DLR), Institute of Atmospheric Physics, Oberpfaffenhofen, Germany
²Atmospheric Physics, Ludwig-Maximilians-Universität München (LMU), Munich, Germany
³Leibniz Institute of Atmospheric Physics (IAP), Kühlungsborn, Germany
⁴Max Planck Institute for Nuclear Physics (MPIK), Heidelberg, Germany
⁵Division of Space and Plasma Physics, Royal Institute of Technology (KTH), Stockholm, Sweden

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¹Kareta, Theodore,²Fuentes-Muñoz, Oscar,¹Moskovitz, Nicholas²Farnocchia, Davide,³Sharkey, Benjamin N. L.
Astrophysical Journal Letters 979, L8 Open Access Link to Article [DOI 10.3847/2041-8213/ad9ea8]
¹Lowell Observatory, Flagstaff, AZ, United States
²Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, 91109, CA, United States
³Department of Astronomy, University of Maryland, 4296 Stadium Dr., PSC (Bldg. 415) Rm. 1113, College Park, 20742-2421, MD, United States

The near-Earth asteroid (NEA) 2024 PT5 is on an Earth-like orbit that remained in Earth’s immediate vicinity for several months at the end of 2024. PT5’s orbit is challenging to populate with asteroids originating from the main belt and is more commonly associated with rocket bodies mistakenly identified as natural objects or with debris ejected from impacts on the Moon. We obtained visible and near-infrared reflectance spectra of PT5 with the Lowell Discovery Telescope and NASA Infrared Telescope Facility on 2024 August 16. The combined reflectance spectrum matches lunar samples but does not match any known asteroid types—it is pyroxene-rich, while asteroids of comparable spectral redness are olivine-rich. Moreover, the amount of solar radiation pressure observed on the PT5 trajectory is orders of magnitude lower than what would be expected for an artificial object. We therefore conclude that 2024 PT5 is ejecta from an impact on the Moon, thus making PT5 the second NEA suggested to be sourced from the surface of the Moon. While one object might be an outlier, two suggest that there is an underlying population to be characterized. Long-term predictions of the position of 2024 PT5 are challenging due to the slow Earth encounters characteristic of objects in these orbits. A population of near-Earth objects that are sourced by the Moon would be important to characterize for understanding how impacts work on our nearest neighbor and for identifying the source regions of asteroids and meteorites from this understudied population of objects on very Earth-like orbits.

^1,2Dorian Leger,¹Fardin Ghaffari-Tabrizi,³ Matthew Shaw,⁴Joshua Rasera,⁵David Dickson,^6,7Baptiste Valentin,⁸Anton Morlock,¹Freja Thoresen,¹Aidan Cowley Proceedings of the National Academy od Science of the USA (PNAS) 122, e2306146122 Link to Article [https://doi.org/10.1073/pnas.2306146122] ¹Spaceship, European Astronaut Center, Exploration Preparation, Research and Technology Team (ExPeRT), Directorate of Human and Robotic Exploration, European Space Agency, Cologne 51147, Germany ²Cx Bio, Luxembourg 2521, Luxembourg ³Future Mining Team, Commonwealth Scientific and Industrial Research Organisation, Mineral Resources, Clayton VIC 3168, Australia ⁴Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, United Kingdom ⁵Center for Space Resources, Colorado School of Mines, Golden, CO 80401, Colorado ⁶Spaceship FR, Centre National d’Etudes Spatial, Toulouse 31400, France ⁷Belgian Air and Space Component, Control & Reporting Centre, Belgian Armed Forces, Brussels 1140, Belgium ⁸Karlsruhe Institute of Technology, Karlsruhe 76131, Germany Spacecraft using combustion engines require substantial amounts of oxygen for their propellant. The Moon could be a source of oxygen for rocket propellant, since the material composing the lunar surface can be processed to extract oxygen. However, little is known about overall energy requirements of the processes described in the literature for oxygen extraction from lunar regolith. This knowledge gap constrains the planning of lunar missions, since the scale of energy infrastructure required for oxygen production facilities is not well characterized. This study presents an energy consumption model for oxygen production via hydrogen reduction of the mineral ilmenite (FeTiO₃). We consider an end-to-end production chain starting from dry regolith as the feedstock. The production includes the following process steps: excavation, transportation, beneficiation, hydrogen reduction, water electrolysis, liquefaction, and zero boil-off storage. The model predicts the energy demand per kilogram oxygen produced based on adjustable parameters for each process step. As expected, the model indicates a strong dependence on feedstock composition. For regolith composed of 10 wt% ilmenite, the model predicts that a total of 24.3 (± 5.8) kWh is needed per kg of liquid oxygen produced. This study confirms that the hydrogen reduction and electrolysis steps have the highest energy requirements in the production chain. Sensitivity analysis reveals that the enrichment factor of the beneficiation process is the most critical parameter for optimizing energy utilization. Overall, this study provides a parameterized end-to-end model of energy consumption that can serve as a foundation for various production systems on the Moon.

^1,2Marine Paquet , ¹Frederic Moynier, ³Paolo A. Sossi, ¹Wei Dai, James M.D. Day
Earth and Planetary Science Letters 656, 119250 Open Access Link to Article [https://doi.org/10.1016/j.epsl.2025.119250]
¹Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, Paris, F-75005, France
²Université de Lorraine, CNRS, CRPG, F-54000, Nancy, France
³Institute of Geochemistry and Petrology, ETH Zürich, Clausiusstrasse 25, Zürich CH-8092, Switzerland
⁴Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0244, USA
Copyright Elsevier

The abundances and isotopic signatures of volatile elements provide critical information for understanding the delivery of water and other essential life-giving compounds to planets. It has been demonstrated that the Moon is depleted in moderately volatile elements (MVE), such as Zn, Cl, S, K and Rb, relative to the Earth. The isotopic compositions of these MVE in lunar rocks suggest loss of volatile elements during the formation of the Moon, as well as their modification during later differentiation and impact processes. Due to its moderately volatile and strongly chalcophile behaviour, copper (Cu) provides a distinct record of planetary accretion and differentiation processes relative to Cl, Rb, Zn or K. Here we present Cu isotopic compositions of Apollo 11, 12, 14 and 15 mare basalts and lunar basaltic meteorites, which range from δ65Cu of +0.55±0.01 ‰ to +3.94±0.04 ‰ (per mil deviation of the 65Cu/63Cu from the NIST SRM 976 standard), independent of mare basalt Ti content. The δ65Cu values of the basalts are negatively correlated with their Cu contents, which is interpreted as evidence for volatile loss upon mare basalt emplacement, plausibly related to the presence Cl- and S-bearing ligands in the vapour phase. This relationship can be used to determine the Cu isotopic composition of the lunar mantle to a δ65Cu of +0.57 ± 0.15 ‰. The bulk silicate Moon (BSM) is 0.5‰ heavier than the bulk silicate Earth (+0.07 ± 0.10 ‰) or chondritic materials (from -1.45 ± 0.08 ‰ to 0.07 ± 0.06 ‰). Owing to the ineffectiveness of sulfide segregation and lunar core formation in inducing Cu isotopic fractionation, the isotopic difference between the Moon and the Earth is attributed to volatile loss during the Moon-forming event, which must have occurred at- or near-equilibrium.

^1,2Matthew J. Genge, ³Matthias Van Ginneken, ⁴Chi Ma, ⁵Martin D. Suttle, ^1,2Natasha Almeida, ⁶Noriko T. Kita, ⁶Mingming Zhang, ⁷Luca Bindi
Earth and Planetary Science Letters 656, 119276 Open Access Link to Articel [https://doi.org/10.1016/j.epsl.2025.119276]
¹Department of Earth Science and Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
²Planetary Materials Group, Natural History Museum, London, SW7 5BD, UK
³Department of Physics and Astronomy, Centre for Astrophysics and Planetary Science, University of Kent, Canterbury, Kent, CT2 7NH, UK
⁴Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA
⁵School of Physical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
⁶Department of Geoscience, University of Wisconsin-Madison, 1215W. Dayton St., Madison, WI, 53706, USA
⁷Dipartimento di Scienze della Terra, Università di Firenze, Via La Pira 4, I, 50121, Florence, Italy
Copyright Elsevier

We report the discovery of Al-Cu-alloys within a coarse-grained micrometeorite from the Congo. Oxygen isotope ratios of the sample are consistent with a CV3 source, similar to the Khatyrka meteorite. The petrology of the micrometeorite is also similar to Khatyrka and testifies to the disequilibrium impact mixing between the CV3 parent body and a differentiated body, which was the source of the Al-Cu-alloys. The oxygen isotope composition, however, suggests either limited mixing with projectile silicates or a differentiated projectile with oxygen isotopes close to the CCAM. The most plausible origin of the Al-Cu-alloys is the desilication of an aluminous igneous protolith by hydrothermal activity under highly reduced conditions. We argue that the ureilite parent body is the most likely source for the projectile owing to its silicic magmatism, late-stage reduction and similar oxygen isotope ratios. Al-Cu-alloys can, thus, be found on the disrupted remnants of such protoplanets.