^1,2Elana G. Alevy,³Tasha L. Dunn,⁴Alexander N. Krot,^4,5Paul Cardon-Pilotaz,⁶Juliane Gross
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14358]
¹Department of Geology, Colby College, Waterville, Maine, USA
²Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, USA
³Department of Geology, Colby College, Waterville, Maine, USA
⁴ Institute of Geophysics and Planetology, School of Ocean and Earth Science Technology, University of Hawai’i at Mānoa, Honolulu, Hawaii, USA
⁵Ecole Normale Supérieure de Lyon, Lyon, France
⁶Astromaterials Acquisition and Curation Office, NASA Johnson Space Center, Houston, Texas, USA
Published by arrangement with John Wiley & Sons

Camel Donga 003 (CD 003) was originally classified as a CK3 chondrite based on its coarse-grained matrix, Ni-rich sulfides, Cr-rich magnetite, and CK-like silicate mineralogy. However, after preliminary backscattered electron imaging and elemental mapping of a 400 mm2 thin section of CD 003, subsequent mineral chemistry analysis confirmed that the sample is a fragmental breccia consisting of three oxidized CV lithologies. In the two largest lithologies, both mineralogically pristine and metasomatically altered refractory inclusions are commonly found in close proximity to one another. This suggests that brecciation and mixing of different lithologies in CD 003 occurred on a submillimeter scale. The least abundant lithology—an 8 × 3 mm clast—is distinguished from the other lithologies by its recrystallized matrix, poorly defined chondrules, and equilibrated olivine (Fa42). The homogeneity of matrix and chondrule olivine indicates that this lithology has been metamorphosed to at least petrologic subtype 3.8 conditions. We can trace the provenance of our sample to the main mass of CD 003, which must contain the CK material described in its original classification. Therefore, the presence of the three oxidized CV lithologies suggests that CD 003 is the first CV/CK3 chondrite breccia.

¹Stu Webb,¹Clive R. Neal,²Bridget Guiza,²James M. D. Day
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14362]
¹Department of Civil & Environmental Engineering & Earth Science, University of Notre Dame, Notre Dame, Indiana, USA
²Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
Published by arrangement with John Wiley & Sons

High-Al Apollo 14 basalt 14053 has been identified as an endogenous partial melt product from the lunar interior based on geochemical analyses, specifically low abundances of highly siderophile elements, but exhibits textural characteristics similar to those of impact melts. Prior studies of this sample have described mineralogical differences between “interior” and “exterior” portions, which have been attributed to exposure at the lunar surface and subsequent metamorphism through subsolidus reheating within or in proximity to an impact-ejecta blanket. It has been demonstrated that quantitative textural analysis is a useful tool for distinguishing between lunar rocks altered by impact processes and those produced by endogenic magmatic processes. Such an approach is used in this study to analyze multiple thin sections cut from interior and exterior portions of 14053. The textural heterogeneity of plagioclase crystals among thin sections revealed in this study suggests that an impact-ejecta blanket likely impinged on the western side of 14053. This thermal metamorphism coarsened the plagioclase grains within that portion of 14053 so intensely that components diffused to form subtle layering and moderate textural heterogeneity that was quantifiable. These results also support previous conclusions that suggest the differences in reduction textures within this sample are due to the limited penetration depth of solar-wind implanted hydrogen prior to reheating. Thermal metamorphism can produce textural changes in lunar samples even if below the solidus temperature, such that the plagioclase texture of an endogenous basalt is sufficiently altered to that resembling an impact melt. These results highlight the significance of quantitative petrographic observations of lunar samples to reveal important petrogenetic information that has to be placed in proper spatial context to be understood.

¹J. Eschrig,¹M. M. M. Meier,^2,3B. A. Hofmann
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14361]
¹Naturmuseum St. Gallen, St. Gallen, Switzerland
²Naturhistorisches Museum Bern, Bern, Switzerland
³Institute of Geological Sciences, University of Bern, Bern, Switzerland
Published by arrangement with John Wiley & Sons

Museums and universities are important for collecting, maintaining, and curating meteorites. To make specimens known and available for research, inventorying and optimal curation are important. However, not all meteorite collections are well curated, especially in smaller institutions. During a 12-month project supported by the Swiss Confederacy under the “SwissCollNet” framework, we viewed, photographed, and inventoried all public and institutional meteorite collections in Switzerland. In total, the 27 collections contain 7616 specimens, derived from 3469 different meteorites. New, switched, and missing specimens were found in many collections. More than half of the collections contained specimens without inventory numbers and unknown or unofficial specimens, several of which could be assigned to a known meteorite fall or find during this project. The identification of switched or unknown samples was done using handheld X-ray fluorescence spectrometry and magnetic susceptibility measurements. In total, 201 specimens were attributed a preliminary classification. We demonstrate the importance of smaller collections, which often hold fragments of rare meteorite types. We underline how large-scale projects like the one presented here allow for unique data, for example, finding specimens missing from one collection in another. By tracking the origin of specimens using historic labels, we show that the history of meteoritics is reflected in the composition of the Swiss collections. During the inventorying process, several prehistoric and modern artifacts made of meteoritic material were found, underlining the potential of analyzing non-geological specimens in museums.

^1,2,3Timothy K. Johnsen,^1,2,4Virginia C. Gulick
American Mineralogist 110, 685-698 Link to Article [https://doi.org/10.2138/am-2023-9072]
¹Planetary Systems Branch, NASA Ames Research Center, MS 239-20, Moffett Field, California 94035, U.S.A.
²SETI Institute, 339 Bernardo Avenue, Suite 200, Mountain View, California 94043, U.S.A.
³Computational Science Research Center, San Diego State University, 5500 Campanile Drive, San Diego, California 92182, U.S.A.
⁴Department of Planetary Sciences, Lunar and Planetary Lab, University of Arizona, 1629 E. University Boulevard, Tucson, Arizona 85721, U.S.A.
Copyright The Mineralogical Society of America

Planetary surface missions have greatly benefitted from intelligent systems capable of semi-autonomous navigation and surveying. However, instruments onboard these missions are not similarly equipped with automated science analysis classifiers onboard rovers, which can further improve scientific yield and autonomy. Here, we present both single- and multi-mineral autonomous classifiers integrated using the results from a co-registered dual-band Raman spectrometer. This instrument consecutively irradiates the same spot size on the same sample using two excitation lasers of different wavelengths (532 and 785 nm). We identify the presence of mineral groups: pyroxene, olivine, potassium feldspar, quartz, mica, gypsum, and plagioclase, in 191 rocks. These minerals are among the major rock-forming mineral groups, so their presence or absence within a sample is key for understanding rock composition and the environment in which it formed. We present machine learning methods used to train classifiers and leverage the multiple modalities of the dual-band Raman spectrometer. When testing on a novel sample set for single-mineral classification, we show accuracy scores up to 100% (varying by mineral), with a total classification rate (all minerals) of 91%. When testing on a novel set of samples for multi-mineral classification, we show accuracy scores up to 96%, with a total classification rate of 73%. We end with several hypothesis tests demonstrating that dual-band Raman spectroscopy is more robust and improves the scientific yield for mineral classification over single-band spectroscopy, especially when combined with our multimodal neural network.

^1,2,3Xiaorong Qin et al. (>10)
American Mineralogist 110, 791-807 Link to Article [https://doi.org/10.2138/am-2024-9374]
¹State Key Laboratory of Deep Earth Processes and Resources, Guangzhou Institute of Geochemistry/ Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
²CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China
³University of Chinese Academy of Sciences, Beijing 100049, China
Copyright: The Mineralogical Society of America

Al-hematite occurs in a wide range of terrestrial soils, but the impact of hydrologic factors on the formation and preservation of Al-hematite remains uncertain. Experimental studies indicate that the ratio of the intensity (I) of the (110) reflection to the intensity of the (104) reflection [(I(110)/I(104)] increases with increasing Al content in a series of synthetic Al-hematite analyzed by X-ray diffraction (XRD), whereas the ratio of the full-width at half maximum of the (110) reflection to the full-width at half maximum of the (104) reflection [W(110)/W(104)] decreases. Quantitative constraints were applied to determine the various levels of Al-substituted hematite in a basaltic laterite (a 48-m-long drill hole) from Hainan Island in South China. The spatial correlation between the distribution of hematite with varying Al content and the location of the groundwater table in the basaltic laterite indicates that hydrologic conditions play a crucial role in regulating the formation and preservation of Al-hematite. The weathering of basalt in a stable water-saturated environment with a relatively slower flow rate promotes the formation of Al-poor hematite. Conversely, the formation of Al-rich hematite was favored by a relatively high flow rate and alternating wet and dry conditions above the groundwater table. Additionally, capillary water in the surficial soil facilitates the expulsion of Al during the recrystallization of Al-rich hematite, resulting in the formation of Al-poor hematite in the surficial soil. Observations from landed instruments and ground-based telescopes have led to the longstanding suspicion that Al-hematite exists on the surface of Mars. The potential presence of Al-hematite in certain martian outcrops may suggest the existence of transient liquid water with slightly higher flow rates, such as episodic floods, emphasizing the dynamic hydrologic conditions on Mars. Moreover, this study suggests that visible and near-infrared (VNIR) spectroscopy can be employed to identify and characterize Al-rich hematite. This approach could be employed to assess the potential presence of Al-rich hematite on Mars, aiding in the study of the planet’s hydrologic environment.

¹J.Gattacceca et al.(>10)
Meteoritics & Planetary Science (in Press) (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14359]
¹CNRS, Aix Marseille Univ, IRD, INRAE, CEREGE, Aix-en-Provence, France
Published by arrangement with John Wiley & Sons

CI1 chondrites are rare meteorites with high scientific value. In fact, they are the most chemically primitive meteorites and show evidence of intense parent-body aqueous alteration. They also share strong similarities with samples from Ryugu and Bennu asteroids returned by the JAXA Hayabusa2 and NASA’s OSIRIS-REx missions. In this work, we present a detailed study of the Oued Chebeika 002 meteorite, a ~420 g CI1 chondrite found in Morocco in 2024. We describe its petrography, texture, and mineralogy, with a focus on clay mineralogy. We provide the bulk and mineral chemical composition, as well as the bulk oxygen, iron, and chromium isotopic compositions. Spectroscopic properties were studied by means of infrared and Raman spectroscopies. We also measured the density, grain density and magnetic properties. Our results confirm that Oued Chebeika 002 is a CI1 chondrite, with close similarities to the other five know CI1 chondrites, and samples from Ryugu and Bennu asteroids. Several lines of evidence indicate that Oued Chebeika 002 has suffered no significant terrestrial alteration. It is more pristine in that regard than Alais, Orgueil and Ivuna CI1 chondrites, and more similar to samples from asteroids Ryugu and Bennu. Subtle differences exist between Oued Chebeika 002 and other CI1 chondrites that cannot be accounted for by terrestrial alteration of the latter. For instance, olivine and calcite were not observed. It is also noteworthy that the magnetic mineral assemblage of Oued Chebeika 002 is significantly different from that of Alais, Ivuna and Orgueil, but undiscernible from that of Ryugu samples. Chromium and iron isotopic composition of Oued Chebeika 002 confirms that CI1 chondrites, like Ryugu samples, are distinct from meteorites belonging to the non-carbonaceous and carbonaceous isotopic groups and may have originated from the same region where ice giant planets and Oort Cloud comets were formed.

¹M. Broussard,¹M. Neuman,¹B. L. Jolliff,¹P. Koefoed,¹R. L. Korotev,²R. V. Morris,³K. C. Welten,¹K. Wang
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2024JE008371]
¹Department of Earth, Environmental, and Planetary Sciences and the McDonnell Center for the Space Sciences,
Washington University in St. Louis, St. Louis, MO, USA
²ARES NASA Johnson Space Center, Houston, TX, USA
³Space Sciences Laboratory, University of California, Berkeley, CA, USA
Published by arrangement with John Wiley & Sons

Space weathering alters the surface materials of airless planetary bodies; however, the effects on moderately volatile elements in the lunar regolith are not well constrained. For the first time, we provide depth profiles for stable K and Fe isotopes in a continuous lunar regolith core, Apollo 17 double drive tube 73001/2. The top of the core is enriched in heavy K isotopes (δ41K = 3.48 ± 0.05‰) with a significant trend toward lighter K isotopes to a depth of 7 cm; while the lower 44 cm has only slight variation with an average δ41K value of 0.15 ± 0.05‰. Iron, which is more refractory, shows only minor variation; the δ56Fe value at the top of the core is 0.16 ± 0.02‰ while the average bottom 44 cm is 0.11 ± 0.03‰. The isotopic fractionation in the top 7 cm of the core, especially the K isotopes, correlates with soil maturity as measured by ferromagnetic resonance. Kinetic fractionation from volatilization by micrometeoroid impacts is modeled in the double drive tube 73001/2 using Rayleigh fractionation and can explain the observed K and Fe isotopic fractionation. Effects from cosmogenic 41K (from decay of 41Ca) were calculated and found to be negligible in 73001/2. In future sample return missions, researchers can use heavy K isotope signatures as tracers of space weathering effects.

^1,2Antonin Wargnier et al. (>10)
Icarus (in Press) Open Access Link to Article [https://doi.org/10.1016/j.icarus.2025.116611]
¹LIRA, Observatoire de Paris, Université PSL, Sorbonne Université, Université de Paris-Cité, CY Cergy Paris Université, CNRS, 5 place Jules Janssen, Meudon, 92195, France
²LATMOS, CNRS, Université Versailles St-Quentin, Université Paris-Saclay, Sorbonne Université, 11 Bvd d’Alembert, Guyancourt, F-78280, France
Copyright Elsevier

^1,2X. Zhu,¹Y. Ye,^2,3R. Caracas
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2024JE008839]
¹State Key Laboratory of Geological Process and Mineral Resources, China University of Geosciences, Wuhan, China
²Institut de Physique du Globe de Paris, CNRS, Université Paris Cité, Paris, France
³The Research Center of the University of Bucharest, Bucharest, Romania
Published by arrangement with John Wiley & Sons

The formation and evolution of rocky planets such as the Earth are marked by the heavy bombardments that dominated the first parts of the accretions. The outcomes of the large and giant impacts depend on the critical points and liquid-vapor equilibria of the constituent materials. Several determinations of the positions of the critical points have been conducted in the last few years, but they have mainly focused on systems devoid of volatiles. Here, we study, for the first time, a volatile-rich ubiquitous model mineral, phlogopite. For this, we employ ab initio molecular dynamics simulations. Its critical point is constrained in the 0.40–0.68 g/cm3 density range and 5,000–5,500 K temperature range. This shows that adding volatiles decreases the critical temperature of silicates while having a smaller effect on the critical density. The vapor phase that forms under cooling from the supercritical state is dominated by hydrogen, present in the form of H2O, H, OH, with oxygen and various F-bearing phases coming next. Our simulations show that up to 93% of the total hydrogen is retained in the silicate melt. Our results suggest that early magma oceans must have been hydrated. In particular for the Moon’s history, even if catastrophic dehydrogenation occurred during the cooling of the lunar magma ocean, the amount of water incorporated during its formation could have been sufficient to explain the amounts of water found today in the last lunar samples.

¹W. H. Farrand et al. (>10)
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2024JE008645]
¹Space Science Institute, Boulder, CO, USA
Published by arrangement with John Wiley & Sons

The Mars Science Laboratory rover, Curiosity, has been examining strata from a period of Martian history where extensive clay mineral formation transitioned to sulfate mineral formation. This mineralogic change corresponds to a change from a wetter to a more arid climate. Among the tools used by Curiosity to study the rocks that recorded this transition is the multispectral capability of its Mast Camera (Mastcam). The Mastcam filter wheel, in combination with its Bayer Pattern filter focal plane array has provided multispectral scenes recorded in 12 spectral bands over the 445–1,013 nm spectral range. Here, Mastcam multispectral results from the rover’s exploration of predominantly sulfate-bearing strata that bracket a distinct dark-toned resistant stratigraphic marker unit, now referred to as the Amapari Marker Band (AMB), are presented in association with supporting information from some of Curiosity’s other instruments. Using an agglomerative hierarchical clustering approach, six spectral classes were derived. These classes included three stratigraphic classes plus a class indicating more intense diagenetic alteration and classes of dark-toned float rocks and a set of Fe-Ni meteorites. These spectral classes were compared to the spectra of analogous terrestrial materials. Among the observations, a distinct tonal and color unit was observed directly below the Amapari Marker Band. Several lines of evidence suggest this narrow interval is an alteration horizon. The alteration could have resulted from diagenesis, exposure as a weathering surface, or from introduction of water associated with the deposition of the lower AMB.