¹Dustin Trail, ²Mélanie Barboni, ¹Miki Nakajima, ^1,3Kim A. Cone
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2025.10.043]
¹Department of Earth & Environmental Sciences, University of Rochester, Rochester, NY, USA
¹School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
³Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, USA
Copyright Elsevier

The Moon underwent extensive internal and external modification following the crystallization of a global magma ocean. However, the isotopic record from this formative period remains poorly constrained. Here, we present the first comprehensive study of coupled δ18OVSMOW and δ30SiNBS28 compositions in 67 lunar zircons from Apollo 14 samples, spanning crystallization ages from 4.34 to 3.93 Ga, a critical 400-million-year window of early lunar history. The zircons exhibit remarkably uniform isotopic compositions throughout this interval, with δ18O = 5.66 ± 0.23 ‰ (1 s.d.) and δ30Si = –0.30 ± 0.16 ‰ (1 s.d.). These values are consistent with both bulk silicate Moon estimates and whole-rock analyses, suggesting minimal isotopic fractionation between zircon-forming melts and their source reservoirs. Importantly, we find no systematic isotopic variations with age, sample, or crystallization temperature. This isotopic uniformity persisted despite large-scale geological processes, including crustal formation, basin-forming impacts, and possible mantle overturn. This implies that neither primary differentiation processes nor later reworking produced detectable Si or O isotope heterogeneities in the zircon source regions, at least within the nearside Procellarum KREEP Terrane. Taken together, these results are consistent with lunar silicate reservoirs being well mixed and isotopically equilibrated by ∼4.3 Ga within Fra Mauro, and possibly more broadly, setting a stringent constraint for models of lunar differentiation.

¹Hairuo Fu, ¹Stein B. Jacobsen
Earth and Planetary Science Letters 672, 119697 Link to Article [https://doi.org/10.1016/j.epsl.2025.119697]
¹Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
Copyright Elsevier

Emerging evidence of strikingly similar Earth–Moon refractory lithophile element compositions provides a key constraint on lunar origin, underscoring the need for a novel framework to test competing Moon formation models. Here, we evaluate whether the canonical giant-impact hypothesis can account for this compositional similarity. We model depth-dependent refractory element heterogeneity within the differentiated Moon-forming impactor and proto-Earth and integrate these chemical signatures with the canonical giant-impact sampling to predict the Moon’s composition. Our modeling shows that the canonical model would lead to a highly fractionated proto-lunar disk composition relative toEarth’s mantle and cannot reproduce the observed Earth–Moon similarity, when mantle compositional differentiation within the pre-impact bodies is considered. This result holds true irrespective of whether density-driven mantle overturn occurred in the pre-impact bodies. Instead, the observed similarity favors extensive post-impact homogenization of the proto-lunar disk, a process consistent with a high-energy giant-impact Moon formation scenario (e.g., Synestia).

¹Robin L. Haller, ¹Martin R. Lee
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1016/j.gca.2025.10.034]
¹School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK
Published by arrangement with John Wiley & Sons

The most abundant group of carbonaceous chondrites are the Mighei-like (CM) meteorites, and they span petrologic types ranging from almost unaltered (CM3) to heavily aqueously processed (CM1). The factors that controlled the extent of aqueous alteration that CM chondrites experienced on their parent body/bodies are debated and remain poorly constrained. Geochemical models, and equilibrium models in particular, are powerful tools for emulating water–rock (W/R) interactions as a function of different parameters and conditions. In order to investigate possible CM chondrite alteration conditions and evaluate controlling factor(s) on petrologic type we modelled the interaction of a CM3 proxy, the CO3.0 chondrite Dominion Range 08006, with a fluid under different temperatures (1–150 °C), W/R ratios (by mass) (0.2–5) and solute concentrations (0.2–2 mol/kg CO2, 0.02–0.2 m NH3, 0.01–0.1 m H2S and 0.001–0.01 m HCl). Five additional scenarios that use the same parameter space but with differences in properties including pressure and redox conditions were also created to further investigate the controls on petrologic type. Systems that are CM chondrite-like from their close similarity to the mineralogy of CM meteorites as determined by sample analysis can form under a wide range of temperatures (1–140 °C), W/R ratios (by mass) (0.3 – 5), solute concentrations (0.2 – 2 m CO2), pH (8.5 – 12.6) and pe (−10.8 – −6.6). Across the different scenarios CM2-like systems are most abundant followed by CM1-like, whereas CM1/2-like systems are rare. Differences in petrologic type can be mainly attributed to variations in temperature, with CM1s overall being formed by alteration at higher temperatures (80–140 °C) than CM2s (1–105 °C). CM1/2 chondrites might be produced by elevated W/R ratios (by mass) and/or solute concentrations. From a mineralogical perspective, CM chondrites of different petrologic type might have originated from contrasting regions of a singular, thermally stratified parent body. Some differences between model results and CM chondrite samples could be addressed by more sophisticated tools like kinetic modelling.

^1,2Martin Bizzarro,^1,3Anders Johansen,⁴Caroline Dorn
Nature Reviews Chemistry 9, 378–396 Link to Article [DOI https://doi.org/10.1038/s41570-025-00711-9]
¹Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Copenhagen, Denmark
²Institut de Physique du Globe de Paris, Université de Paris, Paris, France
³Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
⁴ETH Zurich, Institute for Particle Physics and Astrophysics, Zurich, Switzerland

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^1,2Ritesh Kumar Mishra,³Kuljeet Kaur Marhas,⁴Justin Ibrahim Simon,⁵Yves Marrocchi,⁵Johan Villeneuve
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.70062]
¹Independent Researcher, Dhawalpur, India
²Veer Kunwar Singh University, Ara, India
³Planetary Sciences Division, Physical Research Laboratory, Ahmedabad, India
⁴Astromaterials Research and Exploration Science Division, NASA-Johnson Space Center, Houston, Texas, USA
⁵Centre de Recherches Pétrographiques et Géochimiques, Nancy, France
Published by arrangement with John Wiley & Sons

Ordinary, enstatite, and Rumuruti type have the lowest abundance of refractory inclusions amongst chondritic meteorites. Calcium-aluminum-rich inclusions (CAIs) within these are hallmarked by a relatively small average diameter of ~45 μm (size range 4–382 μm). One CAI, one amoeboid olivine aggregate (AOA), one spinel-bearing chondrule, and two aluminum-rich chondrules from Semarkona (LL3.00) along with one CAI each from Allan Hills (ALHA) 81251 (LL3.2) and Chainpur (LL3.4) were identified following an extensive search. These objects were studied for their petrography, mineral chemistry, relative (26Al) chronology, and three oxygen isotopic compositions. The initial 26Al/27Al ratio of (4.96 ± 0.14) × 10−5 (2σ) in a type A CAI in Chainpur, the largest size (1500 × 1200 μm) found so far in the noncarbonaceous (ordinary) chondrites, forming in an 16O-rich early solar system reservoir (Δ17O = −24‰) is consistent with previous studies. The Chainpur CAI 1 has a Wark–Lovering rim, the first reported case within the noncarbonaceous chondrites. The hibonite–pyroxene spherule in ALHA81251 (CAI 1) is the first reported case of a hibonite–pyroxene spherule in the ordinary chondrites of these rare objects (~12 known so far) within meteorites. The hibonite–pyroxene spherule in ALHA81251 has a low abundance of 26Al/27Al ratio of (1.2 ± 0.6) × 10−5 with Δ17O of ~ −14.5‰ ± 2.0‰. An olivine-phyric Al-rich chondrule in Semarkona (Ch 54) formed at ~0.9 Ma with Δ17O of ~0‰, while Semarkona (Ch 44) formed in a relatively 16O-rich reservoir with Δ17O of ~ −2.0‰. The spinel-bearing chondrule in Semarkona (Ch 205) shows no resolved excess in Δ26Mg and has a planetary-like oxygen isotopic composition. Oxygen isotope composition and 26Al-26Mg relative chronology of these objects confirm their origin and evolution under cosmochemical conditions similar to their “typical” carbonaceous kindred and extend the knowledge of the cosmochemical environment in the early solar system.

¹Takumi Miura,²Hidenori Terasaki,^2,3Hyu Takaki,²Kotaro Kobayashi,⁴Geoffrey David Bromiley,²Takashi Yoshino
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.70068]
¹Department of Earth and Space Science, Osaka University, Osaka, Japan
²Department of Earth Sciences, Okayama University, Okayama, Japan
³Institute for Planetary Materials, Okayama University, Tottori, Japan
⁴School of Geosciences, The University of Edinburgh, Edinburgh, UK
Published by Arrangement with John Wiley & Sons

During precursor stages of planet formation, many planetesimals and planetary embryos are considered to have differentiated, forming an iron-alloy core and silicate mantle. Percolation of liquid iron-alloy in solid silicates is one of the major possible differentiation processes in these small bodies. Based on the dihedral angles between Fe-S melts and olivine, a criterion for determining whether melt can percolate through a solid, it has been reported that Fe-S melt can percolate through olivine matrices below 3 GPa in an oxidized environment. However, the dihedral angle between Fe-S melts and orthopyroxene (opx), the second most abundant mineral in the mantles of small bodies, has not yet been determined. In this study, high-pressure and high-temperature experiments were conducted under the conditions of planetesimal and planetary embryo interiors, 0.5–5.0 GPa, to determine the effect of pressure on the dihedral angle between Fe-S melts and opx. Dihedral angles tend to increase with pressure, although the pressure dependence is markedly reduced above 4 GPa. The dihedral angle is below the percolation threshold of 60° at pressures below 1.0–1.5 GPa, indicating that percolative core formation is possible in opx-rich interiors of bodies where internal pressures are lower than 1.0–1.5 GPa. The oxygen content of Fe-S melt decreases with increasing pressure. High oxygen contents in Fe-S melt reduce interfacial tension between Fe-S melt and opx, resulting in reduced dihedral angles at low pressure. Combined with previous results for dihedral angle variation of the olivine/Fe-S system, percolative core formation possibly occurs throughout bodies up to a radius of 1340 km for an olivine-dominated mantle, and up to 770 km for an opx-dominated mantle, in the case of S-rich cores segregating under relatively oxidizing conditions. For mantles of small bodies in which abundant olivine and opx coexist, the mineral with the largest volume fraction and/or smallest grain size will allow formation of interconnected mineral channels, and, therefore, the wetting property of this mineral determines the wettability of the melt, that is, controls core formation.

¹A.R.Russell et al. (>10)
Journal of Geophysical Reserac (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2025JE009244]
¹Arizona State University, Tempe, AZ, USA
Published by arrangement with John Wiley & Sons

The Martian surface preserves evidence of a global climate transition from wetter to drier conditions, but the nature of the fluids involved in this evolution remains poorly constrained. In Gale crater, the clay-sulfate transition and presence of evaporite mineral assemblages can provide insights into the properties of these fluids and the timing of environmental change. While traversing through the Chenapau member of the sulfate-bearing unit in Gale crater, the Curiosity rover encountered a set of dark-toned veins enriched in Na and Cl, suggestive of halite. However, previous halite detections in Gale crater have been limited to occurrences along the edges of Ca-sulfate veins or nodules, suggesting a unique origin for this set of veins. Here, we hypothesize that these veins formed through the infiltration of saline fluids along pre-existing hydraulically induced fractures. These fluids permeated into the host rock beyond the primary fractures, precipitating halite and cementing the fractures. Using Mastcam and ChemCam spectra, we found that the veins displayed a downturn in the near-infrared wavelengths, consistent with the presence of ferrous iron. Furthermore, textural analysis of the veins reveals host rock material preserved within the veins. ChemCam laser-induced breakdown spectroscopy observations also support the presence of a minor Fe component in the veins and halite concentrated along the center of the fractures. Our results demonstrate that these veins represent a distinct class of diagenetic features in Curiosity’s mission that record an important transition in near-surface fluid chemistry consistent with a transition to a drier environment.

¹Lars E. Borg, ¹Thomas S. Kruijer, ¹Ming-Chang Liu, ^1,2Autumn G. Roberts, ¹Josh Wimpenny, ¹Ouyanatu N.Z. Maina, ¹Joseph Boro, ¹Charles K. Shearer, ^1,4Kyle M. Samperton
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2025.10.028]
¹Cosmochemical & Isotopic Signatures Group, Lawrence Livermore National Laboratory, 7000 East Avenue L-231, Livermore, CA 94550, USA
²Geological Sciences, University of Colorado, Boulder, CO 80309, USA
³Department of Earth and Planetary Science, Institute of Meteoritics, University of New Mexico, Albuquerque, NM 87131, USA
⁴Trace Nuclear Measurement Technology Group, Savannah River National Laboratory, Aiken SC 29802 USA
Copyright Elsevier

Temporal relationships among the three most common suites of lunar crustal rocks have been investigated by obtaining new high precision ages on Felsic/Alkali-suite Quartz monzodiorite Clast B from breccia 15405 and Magnesian-suite norite 78235/6/8/55/56 and comparing them to previously dated ferroan anorthosite sample 60025. The weighted average age of 4337.19 ± 0.49 Ma of 15405 Clast B is defined by zircon U-Pb and Pb-Pb ages as well as mineral isochron Sm-Nd and Nd-Nd ages. It is identical to the weighted average age for Apollo 17 norite 78235/6/8/55/56 of 4334.1 ± 3.5 Ma which is defined by Pb-Pb ages measured on baddeleyites in this investigation and less precise Pb-Pb and Sm-Nd ages reported in the literature. Both ages are ∼ 25 Ma younger than the weighted average of Sm-Nd and Pb-Pb ages reported in the literature on ferroan anorthosite 60025 of 4359.3 ± 2.3 Ma. The fact that ages of all three samples are defined by multiple U-Pb, Pb-Pb, Sm-Nd, and 142Nd-143Nd chronometers provide confidence that they record the igneous crystallization history of the samples and do not represent disturbances or mixing lines with no temporal significance.
The extent to which these three ages represent broader scale magmatism is difficult to evaluate. Nevertheless, the age defined for 15405 Clast B, 78235/6/8/55/56, and 60025 are contemporaneous with the peak of ages observed in detrital zircons from the Apollo 12, 14, 15, and 17 landing sites (4340 ± 20 Ma), a Mg-suite Sm-Nd whole rock isochron defined by samples from Apollo 14, 15, 16, and 17 landing sites (4348 ± 25 Ma), and a Ferroan Anorthosite-suite Sm-Nd whole rock isochron defined by samples from the Apollo 15 and 16 landing sites (4354 ± 29 Ma). This implies that Ferroan Anorthosite-suite magmatism is temporally distinct and earlier than magmatism associated with the Mg-suite and the Felsic/Alkali-suite, as predicted by the lunar magma ocean model of lunar differentiation. The short 35 ± 10 Ma interval between primary ferroan anorthosite magmatism and secondary magmatism suggests that the lunar crust formed over a limited period of time. Although heat from decay of long-lived isotopes, large impacts, tidal heating associated with interactions between the Earth and Moon, and density driven overturn of the magma ocean have all been invoked to explain production of ancient secondary crustal magmatism, only tidal heating and cumulate overturn are consistent with the apparent short duration of secondary crustal magmatism and the great depth of crystallization implied for some Mg-suite samples.
The initial ε143Nd values derived from the 15405 Clast B and 78238 Mg-suite norite isochrons, as well as a Mg-suite whole rock isochron are −0.23 ± 0.11, −0.27 ± 0.74, and −0.25 ± 0.09, respectively. They are identical within uncertainty indicating that Mg-suite and Felsic/Alkali-suite magmas were derived from materials that had the same time averaged Sm/Nd ratios since the formation of the solar system. This, combined with the contemporaneous nature of 15405 Clast B and 78235/6/8/55/56 Mg-suite norite, is consistent with evolution of both samples, and likely both magma suites, from a common source through closed system fractional crystallization or partial melting processes.

¹Rainer Wieler,¹Donald S. Burnett
ACS Earth and Space Chemistry 9, 1142-1151 Link to Article [https://doi.org/10.1021/acsearthspacechem.5c00009]
¹Department of Earth and Planetary Sciences, ETH Zürich, 8092 Zürich, Switzerland
²Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, United States

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¹Ashwani Raju, ²Saraah Imran, ¹Jiwantika Kumari, ¹Ankit Kumar, ³Ramesh P. Singh
Advances in Space Research 76, 1172-1195 Link to Article [https://doi.org/10.1016/j.asr.2025.04.079]
¹Remote Sensing & GIS Lab., Department of Geology, Institute of Science, Banaras Hindu University, Varanasi 221005 Uttar Pradesh, India
²Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
³School of Life and Environmental Sciences, Schmid College of Science and Technology, Chapman University, Orange, United States

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