¹Kelsey B. Prissel,¹Michael J. Krawczynski,²Nicole X. Nie,²Nicolas Dauphas,
²Sarah M. Aarons,²Andy W. Heard,³Michael Y. Hu,³E. Ercan Alp,³Jiyong Zhao
Geochimica et Cosmochimica Acta (in Press) Open Access Link to Article [https://doi.org/10.1016/j.gca.2024.01.006]
¹Department of Earth and Planetary Sciences, Washington University in St. Louis, 1 Brookings Drive, St. Louis, 63123, MO, USA
²Origins Laboratory, Department of Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, 5734 South Ellis Avenue, Chicago, 60637, IL, USA
³Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, 60439, IL, USA
Copyright Elsevier

Basaltic volcanism on the Moon produced low- and high-Ti mare basalt suites that are also distinct with respect to their iron, titanium, and magnesium isotopic compositions. Here, the equilibrium fractionation of Fe and Ti isotopes between ilmenite and melt was experimentally investigated in order to evaluate the role of ilmenite in generating the isotopic compositional variability among the lunar mare basalts. Ilmenite crystallization experiments were conducted using two bulk compositions: an ilmenite-saturated basaltic andesite and an ilmenite-saturated Apollo 14 black glass, and the Fe and Ti isotopic compositions of the experimental ilmenites and glass (quenched melt) were analyzed using solution MC-ICPMS after hand-picking. Additionally, Nuclear Resonant Inelastic X-ray Scattering (NRIXS) measurements on synthetic ilmenite were conducted and compared to previous NRIXS measurements on synthetic lunar glasses in order to derive temperature-dependent equilibrium ilmenite-melt Fe isotopic fractionations. Experimentally determined ilmenite-melt fractionations were then incorporated into a lunar magma ocean crystallization model that tracks the major element and isotopic compositional evolution of lunar magma ocean cumulates and residual liquid. There is good agreement between the Fe equilibrium isotopic fractionation measured by NRIXS and the laboratory equilibration experiments, and we find that the isotopic fractionation is sensitive to ilmenite compositional differences (0 vs. 10% Fe³⁺). Further, the light Ti isotopic composition of ilmenite relative to the melt (Δ49Ti‰=ilmenite-melt−0.09±0.03‰ at 1100 ^∘C) is consistent with the higher coordination of Ti in ilmenite relative to melts and results of previous studies. The modeled Ti isotopic compositions for lunar magma ocean cumulates display Ti isotopic variability sufficient to explain the low- and high-Ti mare basalt sources. However, the difference in Fe isotopic composition between the low- and high-Ti mare basalts cannot be attributed solely to ilmenite fractionation. Instead, Fe isotopic fractionation by additional products of lunar magma ocean crystallization, such as clinopyroxene, is required to generate the inferred Fe and Mg isotopic variability in the lunar mantle. Alternatively, the Fe and Mg isotopic compositions of the lunar mare basalts may indicate Fe-Mg interdiffusion has occurred in the Ti-rich component of the mare basalt source regions via reaction between ilmenite cumulates and the olivine- and pyroxene-rich lunar mantle.

^1,2Hasnaa Chennaoui Aoudjehane
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14126]
¹GAIA Laboratory, Faculty of Sciences Ain Chock, Hassan II University of Casablanca, Casablanca, Morocco
²ATTARIK Foundation for Meteoritics and Planetary Science, Casablanca, Morocco
Published by arrangement with John Wiley & Sons

Morocco is known for the high number of meteorites collected in its territory, including finds and falls. This is explained by the large size of the Moroccan Sahara, the guarantee of security in this desert, and the large community of well-trained Moroccan hunters and nomads who roam through it. Despite this richness, most meteorites collected in Morocco are sold abroad and exported. The exportation of meteorites as well as other geoheritage samples such as fossils and minerals was not completely legal or illegal as there was no dedicated regulation. Since 2000, the APPGM (Association pour la Protection du Patrimoine Géologique du Maroc) a Non-Governmental Organization (NGO) dedicated to the preservation of the Moroccan geoheritage began working with the Moroccan Geological Survey, on a draft of a specific law dedicated to geoheritage. It was fundamental to benefit from the experience of other countries with a high number of meteorites where exportation is not allowed and that are losing their meteorites to illegal exportation. The author recommended a win-win regulation that would allow the legal collection and exportation of meteorites under clear rules benefiting both hunters and scientists but also the country. In 2014, Morocco updated its law regarding mines. One article cited geoheritage as including fossils, minerals, and meteorites and mentioned that their collection and exportation would be regulated by decree. In 2019, the Moroccan Geological Survey and APPGM prepared the application decree of this article that has been discussed and approved by the Moroccan government and implemented in February 2020. This situation is unique in the region as well as compared to the other countries with a high potential of meteorites collection. Meteorite researchers and collectors all over the world should be aware of this regulation in Morocco to make their acquisitions legal. They should request a copy of the “End of the work” from local traders, the receipt from the Geological survey, and the certificate of export from customs. It is an important ethical and scientific responsibility of our community.

¹Ryota Fukai et al. (>10)
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14121]
¹Japan Aerospace Exploration Agency, Tokyo, Japan
Published by arrangement with John Wiley & Sons

Japan Aerospace Exploration Agency’s Martian Moons eXploration (MMX) mission will launch a spacecraft in 2024 to return samples from Phobos in 2029. Curatorial work for the returned Phobos samples is critical for the sample allocation without degrading the sample integrity and subsequent sample analysis that will provide new constraints on the origin of Phobos and the evolution of the circum-Mars environment. The Sample Analysis Working Team of the MMX is designing the sample curation protocol. The curation protocol consists of three phases: (1) quick analysis (extraction and mass spectrometry for gases), (2) pre-basic characterization (bulk-scale observation), and (3) basic characterization (grain-by-grain observation and allocation of the sample aliquots). Nondestructive analyses within the clean chamber (e.g., visible and near-infrared spectral imaging) and outside the chamber (e.g., gas mass spectrometry) are incorporated into the curation flow in coordination with the MMX mission instrument teams for ground-truthing the remote-sensing data sets. The MMX curation/sample analysis flow enables the seamless integration between the sample and remote-sensing data sets to maximize the scientific value of the collected Phobos samples.

¹Aruto Kashima,^1,2Shu-hei Urashima,^1,2Hiroharu Yui
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14123]
¹Department of Chemistry, Faculty of Science, Tokyo University of Science, Tokyo, Japan
²Water Frontier Research Center, Research Institute for Science and Technology, Tokyo University of Science, Tokyo, Japan
Published by arrangement with John Wiley & Sons

Chemical states of carbon in terrestrial (meta) sediments and carbonaceous chondrites gather attention as a geothermometer. As a nondestructive analytical method, Raman spectroscopy has been widely used to study their electronic properties, crystallinity, and structural defects through so-called D and G bands. For the analysis of Raman spectra, a common problem is coexistence of a fluorescence background, which should be subtracted prior to the peak-fitting analysis. However, we recently faced a problem that the band shape noticeably changed depending on the background function assumed although the background seemed to be well subtracted at a first glance regardless of the choice of the background function. For the application of the Raman spectroscopy as a geothermometer, a standard background subtraction method must be established to suppress the arbitrariness. In the present study, Raman spectra of seven carbon-containing natural samples, whose background intensities were significantly different, were measured, and their background shape was evaluated by first-, second-, and third-order polynomials. The results indicated that the third-order polynomial was necessary and sufficient as a standard background function. Importantly, although lower order polynomials seem to successfully fit the background at a first glance, they falsely caused dispersion of the shoulder band shape.

¹Van T. H. Phan et al.(>10)
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14122]
¹Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), CNRS, Université Grenoble Alpes, Grenoble, France
Published by arrangement with John Wiley & Sons

The Hayabusa2 mission from the Japan Aerospace Exploration Agency (JAXA) returned to the Earth samples of carbonaceous asteroid (162173) Ryugu. This mission offers a unique opportunity to investigate in the laboratory samples from a C-type asteroid, without physical or chemical alteration by the terrestrial atmosphere. Here, we report on an investigation of the mineralogy and the organo-chemistry of Hayabusa2 samples using a combination of micro- and nano-infrared spectroscopy. Particles investigated with conventional FTIR spectroscopy have spectra dominated by phyllosilicate-related absorption, as observed for samples of CI-chondrites, selected ungrouped carbonaceous chondrites, and selected hydrated micrometeorites. Ryugu samples show smaller sulfate-related absorption than CI-chondrites. Our samples that were only briefly exposed to the Earth atmosphere show absorptions related to molecular water, revealing fast terrestrial contamination of the spectral signature at 3 μm. Overall, our FTIR data are in agreement with other work done on Ryugu samples, revealing a low degree of mineralogical variability across Ryugu samples. AFM-IR mapping of the grains shows the presence of a micrometer-sized organic globule in one of our analyzed grains. The AFM-IR spectra obtained on this globule are similar to IR spectra obtained on IOM suggesting that it is constituted of refractory organic matter. This globule may host silicate in its interior, with a different mineralogy than bulk Ryugu phyllosilicate. The shape, presence of peculiar silicate, and the nature of organic constituting the globule point toward a pre-accretionary origin of this globule and that at least part of Ryugu organics were inherited from the protosolar nebulae or the interstellar media. Altogether, our results show the similarities between Ryugu samples and CI chondrites.

¹K. H. Joy et al. (>10)
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14114]
¹Department of Earth and Environmental Sciences, University of Manchester, Manchester, UK
Published by arranfgement with John Wiley & Sons

The Lost Meteorites of Antarctica project was the first UK-led Antarctic meteorite recovery expedition. The project has successfully confirmed two new high-density meteorite stranding zones in the Hutichison Icefield and Outer Recovery Icefields areas and investigated the geology of three previously unvisited Antarctic nunataks (Turner Nunatak, Pillinger Nunatak, Halliday Nunatak). The project undertook meteorite searching on the ice surface via skidoo reconnaissance and systematic searching and developed a novel pulse induction metal detection system to search for englacial iron-rich meteorites trapped within the upper one meter of ice. In total, 121 meteorites have been recovered from the ice surface searching activities, which are now curated in the United Kingdom at the Natural History Museum London and are available for scientific analysis.

^1,2,3Jinfei Yu,^1,3,4Haibin Zhao,⁵Edward A. Cloutis,^3,6Hiroyuki Kurokawa,^1,7Yunzhao Wu
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2024.115951]
¹Key Laboratory of Planetary Sciences, Purple Mountain Observatory, CAS, Nanjing 210023, China
²School of Astronomy and Space Science, University of Science and Technology of China, Hefei 230026, China
³Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
⁴CAS Center for Excellence in Comparative Planetology, CAS, Hefei 230026, China
⁵Centre for Terrestrial and Planetary Exploration, University of Winnipeg, Winnipeg, Manitoba R3B 2E9, Canada
⁶Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
⁷State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Macau, China
Copyright Elsevier

Carbonaceous chondrites (CCs) are windows into the early Solar System and the histories of their parent bodies. Their infrared spectral signatures are powerful proxies for deciphering their composition and evolution history, but still present formidable challenges in relation to determining the degree of secondary processing such as aqueous alteration and thermal metamorphism via comprehensive data and mid-infrared feature. In our study, we delved into the infrared spectra spanning 1–25 μm of 17 CCs, with distinct petrological characteristics and varying degrees of alteration. Through this investigation, we uncovered distinct spectral patterns that shed light on the processes of alteration and metamorphism. As aqueous alteration intensifies, two key spectral features, the 3 μm-region absorption feature associated with OH-bearing minerals and water, and the 6 μm band indicative of water molecules, both grow in intensity. Simultaneously, their band centers shift towards shorter wavelengths. Moreover, as alteration progresses, a distinctive absorption feature emerges near 2.72 μm, resembling the OH absorption feature found in serpentine and saponite minerals. Comparison of aqueous alteration to laboratory-heated CCs suggests that the 3 μm region OH/H2O absorption feature differs between CC heated to less than or more than ~300 °C. Further insights are gained by examining the vibrational features of silicate minerals, notably influencing the 10 μm and 20 μm regions. The 12.4 μm /11.4 μm reflectance ratio diminishes, and the reflectance peak in the 9–14 μm range shifts towards shorter wavelengths. These changes are attributed to the transformation of anhydrous silicates into phyllosilicates. In the 15–25 μm region, the influence of thermal metamorphism becomes evident and results in the appearance of more spectral features, the single reflectance peak at 22.1 μm undergoes a transformation into two distinct peaks at 19 μm and 25 μm, which is primarily attributed to the increased presence of anhydrous silicates and olivine recrystallization. These findings offer novel insights into the volatile-rich compositions of C-complex asteroids and the thermal evolution histories of their parent bodies.

^1,2Kierra A. Wilk,¹J.F. Mustard,¹R.E. Milliken,¹C.M. Pieters
Icarus (in Press) Open Access Link to Article [https://doi.org/10.1016/j.icarus.2024.115945]
¹Brown University, Providence, RI, United States of America
²NASA Goddard Space Flight Center, Greenbelt, MD, United States of America
Copyright Elsevier

Spectral variations due to the removal of surface adsorbed H₂O at 3 and 6 μm in reflectance spectra on lunar soils and relevant minerals (olivine, pyroxene, and plagioclase) have been assessed. This study characterizes variations in hydration features as a function of lunar relevant surface temperatures, to further understand current (i.e., M³, HRI-IR, VIMS) and future (i.e., Lunar Trailblazer) observations of diurnal changes in surface hydration. Additionally, we explore the utility of using the 6 μm H₂O feature to discern the speciation of surface hydration at 3 μm. We perform controlled temperature measurements (25–200 °C) in a Linkam THMS600 Environmental Stage fixed to a Bruker LUMOS Microscope Fourier Transform IR (μFTIR) spectrometer. We observe clear and systematic changes in the strength of the 3 μm H₂O/OH feature associated with the thermal removal of adsorbed H₂O, in addition to changes in the overall shape and band position of the feature in both the terrestrial and lunar samples. The strength of the 3 μm feature for the compositionally distinct and relatively brighter Apollo highland soil (62231) is stronger and more symmetric than the 3 μm feature observed for the darker mare soil (10084). While several silicate related absorption features are identified near 6 μm, neither a distinguishable hydration feature nor any changes in reflectance that could be attributed to the presence or a change in the amount of surface adsorbed H₂O were observed at 6 μm.

¹Bahae-eddine Mouloud et al. (>10)
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14124]
¹CNRS, INRAE, Centrale Lille, UMR 8207-UMET-Unité Matériaux et Transformations, Université de Lille, Villeneuve d’Ascq, France
Published by arrangement with John Wiley & Sons

Ryugu asteroid grains brought back to the Earth by the Hayabusa2 space mission are pristine samples containing hydrated minerals and organic compounds. Here, we investigate the mineralogy of their phyllosilicate-rich matrix with four-dimensional scanning transmission electron microscopy (4D-STEM). We have identified and mapped the mineral phases at the nanometer scale (serpentine, smectite, pyrrhotite), observed the presence of Ni-bearing pyrrhotite, and identified the serpentine polymorph as lizardite, in agreement with the reported aqueous alteration history of Ryugu. Furthermore, we have mapped the d-spacings of smectite and observed a broad distribution of values, ranging from 1 to 2 nm, with an average d-spacing of 1.24 nm, indicating significant heterogeneity within the sample. Such d-spacing variability could be the result of either the presence of organic matter trapped in the interlayers or the influence of various geochemical conditions at the submicrometer scale, suggestive of a range of organic compounds and/or changes in smectite crystal chemistry.

^1,2,3,4S.N. Valencia,¹R.L. Korotev,¹B.L. Jolliff
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2023.12.034]
¹Department of Earth & Planetary Sciences and the McDonnell Center for the Space Sciences, Washington University in St.Louis, St. Louis, MO 63130
²Department of Astronomy, University of Maryland, College Park, MD 20742
³NASA Goddard Space Flight Center, Greenbelt, MD 20771
⁴Center for Research and Exploration in Space Science and Technology, NASA/GSFC, Greenbelt, MD 20771
Copyright Elsevier

We report bulk rock composition and mineral chemistry of previously unstudied fragments and thin sections of lunar granitic breccia 12013. Instrumental Neutron Activation Analysis data on 25 fragments indicate that the 12013 breccia can be described as a three-component system comprising granitic, rare earth element (REE)-rich, and mafic components. The granitic component is low in FeO and REE but rich in K2O, Th, and associated incompatible elements. The REE-rich component has an elevated concentration of REE, moderate FeO, and low concentrations of those elements that are high in the granitic component, in other words, its composition is complementary to that of the granitic component. The mafic component is richest in FeO, and low in those elements that are concentrated in the granitic and REE-rich components. Petrographically, the REE-rich component is an impact melt breccia with a composition unique to Apollo 12 impact melt breccias. Trace-element concentrations in the REE-rich component indicate that its protolith is possibly monzogabbro, although its composition is significantly more magnesian than other known lunar monzogabbros. The mafic component is dominated by fine-grained pyroxene and plagioclase that appear to have recrystallized after impact. However, preserved lithic clasts with an igneous texture occur in the mafic component and are inferred to represent its protolith. The textures of the preserved mafic lithic fragments and lack of Mg-Fe zoning in pyroxene indicate that the protolith of the mafic component formed either as a crustal intrusion or at the bottom of a thick lava flow. The composition of the mafic component is unlike any previously studied mare basalt samples. Textures of this complex breccia suggest that the granitic breccia was first incorporated with the mafic component to form the “gray breccia”, and that the gray breccia was then incorporated with the REE-rich component while the components were still in a hot, plastic state. The complementary trace-element compositions, including the REE patterns, indicate that the petrogenesis of the granitic and REE-rich components are related. We infer that silicate-liquid immiscibility is likely not the formation mechanism for the 12013 components. Instead, bimodal volcanism owing to basaltic underplating may have led to the formation of the 12013 components.