¹Huidobro, Jennifer,¹Aramendia, Julene,¹García-Florentino, Cristina,¹Población, Iratxe,¹Castro, Kepa,¹Arana, Gorka,¹Madariaga, Juan Manuel
Journal of Raman Spectroscopy (in Press) Open Access Link to Article [DOI 10.1002/jrs.6558]
¹Department of Analytical Chemistry, University of the Basque Country (UPV/EHU), Bilbao, Spain

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¹J. F. Pernet-Fisher,¹K. H. Joy,¹M. E. Hartley
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2022JE007570]
¹Department of Earth and Environmental Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL UK
Published by arrangement with John Wiley & Sons

Rocks of the lunar granulite suite are the product of high-temperature metamorphism within the Moon’s crust. However, to date, their formation conditions have few constraints. Here we combine Ti-in-pyroxene element diffusion modelling and two-pyroxene thermometry with thermal modelling of the lunar crust in order to assess potential heat sources that could generate granulite metamorphism within the lunar highland crust. For the samples investigated in this study, the pyroxene crystals experienced peak metamorphic temperatures between ∼1027 and 1091 ºC over timescales ranging from ∼153 years to ∼15.1 kyrs. To best satisfy these temperature and timescale constraints, hot (∼2300 ºC) impact melt sheets with thickness ranging from 350 m to 3.35 km – equating to impact crater diameters between ∼60 and 280 km – have the potential to heat the underlying anorthositic crust. Deep (>20 km) igneous bodies, such as the large (>10 km thick) sills observed by the GRAIL mission near the base of the lunar crust, also have the potential to generate the required peak metamorphic temperatures; however, the thermal equilibration timescales in this scenario are modelled to be much larger (> 100 kyrs) than was witnessed by the granulites investigated. Our modelling highlights that, while lunar granulites are only a minor component within the Apollo and meteorite collection, they are likely an important and ubiquitous lithology within the lunar highland crust.

^1,2M. Darby Dyar,¹Sydney M. Wallace,^1,2Thomas H. Burbine,³Daniel R. Sheldon
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115718]
¹Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719-2395, USA
²Department of Astronomy, Mount Holyoke College, 50 College St., South Hadley, MA 01075, USA
³College of Information and Computer Sciences | 140 Governors Dr., Amherst, MA 01003, USA
Copyright Elsevier

Understanding the distribution of matter within our Solar System requires a robust methodology for evaluating the composition of small objects in the asteroid belt. Existing asteroid taxonomies have variously been based on spectral features relating to mineralogy and on classification of asteroid spectra alone. This project tests a fundamentally different approach, using machine learning algorithms to classify asteroids based on spectroscopic characteristics of existing meteorite classes. After evaluating four classification techniques built on labeled meteorite spectral data, logistic regression (LR) was determined to provide the most accurate results that distinguish eight robust groups of meteorite classes to which asteroid spectra can then be matched. The groups are rooted in mineralogical composition and directly relate meteorites to potential host bodies. A standalone LR algorithm classifies unknown asteroid spectra uniquely as one of eight specific group, allowing the distribution of compositions in the asteroid belt to be evaluated.

¹Qi, Xiaobin,^1,2Ling, Zongcheng,¹Liu, Ping,¹Chen, Jian,¹Cao, Haijun,¹Liu, Changqing,¹Wang, Xiaoyu,¹Liu, Yiheng
Eartzh and Space Science 10, e2023EA002825 Open Access Link to Article [DOI 10.1029/2023EA002825]
¹Shandong Key Laboratory of Optical Astronomy and Solar—Terrestrial Environment, School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai, China
²CAS Center for Excellence in Comparative Planetology, Chinese Academy of Sciences, Hefei, China

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^1,2,3Gerrit ³ L.H. Tissot,^2,4Thorsten Kleine,³Ren T. Marquez
Geochemistry (Chemie der Erde) (in Press) Link to Article [https://doi.org/10.1016/j.chemer.2023.126007]
¹Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA
²Institut für Planetologie, University of Münster, 48149 Münster, Germany
³The Isotoparium, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
⁴Max Planck Institute for Solar System Research, 37077 Göttingen, Germany
Copyright Elsevier

Mass-independent (nucleosynthetic) Mo isotope anomalies are uniquely useful for constraining genetic relationships among meteoritic and planetary materials and, by extension, the origin and nature of Earth’s late-stage building blocks. The meaningful interpretation of such data, however, critically depends on the accurate correction of any natural and analytical mass-dependent isotope fractionation, which is commonly assumed to follow the ‘exponential law’. Here, using new high-precision Mo isotope data for a diverse set of terrestrial samples, we show that mass-dependent Mo isotope fractionation in nature typically does not adhere to this law, but is instead dominated by equilibrium and Rayleigh processes. We demonstrate that even moderate degrees of such non-exponential fractionation (i.e., mass-dependent isotope fractionation deviating from the exponential law) can result in significant spurious mass-independent Mo isotope anomalies that, when misinterpreted as nucleosynthetic anomalies, can lead to erroneous conclusions, particularly with respect to Earth’s accretion history. Consequently, assessing the magnitude and origin of mass-dependent fractionation will be essential for future efforts to precisely determine the mass-independent Mo isotope composition of bulk silicate Earth and to identify potential nucleosynthetic isotope anomalies in terrestrial rocks.

^1,2Tang, Xuhai,¹Xu, Jingjing,¹Zhang, Yiheng,³Zhao, Haifeng,⁴Paluszny, Adriana,³Wan, Xue,¹Wang, Zhengzhi
Engineering Geology 321, 107154 Link to Article [DOI 10.1016/j.enggeo.2023.107154]
¹School of Civil Engineering, Wuhan University, Hubei, Wuhan, 430072, China
²Wuhan University Shenzhen Research Institute, Shenzhen, 518057, China
³Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences, Beijing, 100094, China
⁴Department of Earth Science and Engineering, Imperial College, London, United Kingdom#

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^1,2Peters, Sophia,^1,2Semenov, Dmitry A.,³Hochleitner, Rupert,^1,2Trapp, Oliver
Scientific Reports (in Press) Open Access Link to Article [DOI 10.1038/s41598-023-33741-8]
¹Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, Munich, 81377, Germany
²Max Planck Institute for Astronomy, Königstuhl 17, Heidelberg, 69117, Germany
³Mineralogische Staatssammlung München, Theresienstr. 41, Munich, 80333, Germany

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¹Yumoto, Koki, ¹Cho, Yuichiro, ^2,3Kameda, Shingo, ¹Kasahara, Satoshi, ^1,4,5Sugita, Seiji
Spectrochimica Acta – Part B Atomic Spectroscopy 205, 106696 Link to Article [DOI
10.1016/j.sab.2023.106696]
¹Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
²Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo, 171-8501, Japan
³Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Kanagawa, Sagamihara, 252-5210, Japan
⁴Research Center of Early Universe, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
⁵Planetary Exploration Research Center, Chiba Institute of Technology, Narashino, 275-0016, Japan

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^1,2V. Fortier,²V. Debaille,^1,3V. Dehant,⁴B. Bultel
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2023.105749]
¹Earth and Life Institute, Université Catholique de Louvain-la-Neuve, Louvain-la-Neuve, Belgium
²Laboratoire G-Time, Université libre de Bruxelles, Bruxelles, Belgium
³Royal Observatory of Belgium, Bruxelles, Belgium
⁴Geosciences Paris Saclay, Université Paris-Saclay, Paris, France

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¹R. J. Curtis,¹H. C. Bates,¹T. J. Warren,¹K. A. Shirley,¹E. C. Brown,¹A. J. King,¹N. E. Bowles
Meteoritics & Planetary Scince (in Press) Link to Article [https://doi.org/10.1111/maps.14055]
¹Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Oxford, UK
²Earth Sciences, Natural History Museum, London, UK
Published by arrangement with John Wiley & Sons

A laboratory study was performed using the Visible Oxford Space Environment Goniometer in which the broadband (350–1250 nm) bidirectional reflectance distribution function (BRDF) of the Winchcombe meteorite was measured, across a range of viewing angles—reflectance: 0°–70°, in steps of 5°; incidence: 15°, 30°, 45°, and 60°; and azimuthal: 0°, 90°, and 180°. The BRDF dataset was fitted using the Hapke BRDF model to (1) provide a method of comparison to other meteorites and asteroids, and (2) to produce Hapke parameter values that can be used to extrapolate the BRDF to all angles. The study deduced the following Hapke parameters for Winchcombe: w = 0.152 ± 0.030, b = 0.633 ± 0.064, and h_S = 0.016 ± 0.008, demonstrating that it has a similar w value to Tagish Lake (0.157 ± 0.020) and a similar b value to Orgueil (0.671 ± 0.090). Importantly, the surface profile of the sample was characterized using an Alicona 3D® instrument, allowing two of the free parameters within the Hapke model φ and �¯, which represent porosity and surface roughness, respectively, to be constrained as φ = 0.649 ± 0.023 and �¯ = 16.113° (at 500 μm size scale). This work serves as part of the characterization process for Winchcombe and provides a reference photometry dataset for current and future asteroid missions.