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NWA 11562: A Unique Ureilite with Extreme Mg-rich Constituents

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1,2Mingbao Li,3,4Ke Zhu,1,5Yan Fan,6P. M. Ranjith,7Chao Wang,1Wen Yu, 1,8,9Shijie Li
The Planetary Science Journal 5, 178 Open Access Link to Article [DOI 10.3847/PSJ/ad6154]
1Center for Lunar and Planetary Sciences, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 55021, People’s Republic of China
2State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Macau 999078, People’s Republic of China
3Freie Universität Berlin, Institut für Geologische Wissenschaften, Malteserstr. 74-100, Berlin 12249, Germany
4Bristol Isotope Group, School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen’s Road, Bristol BS8 1RJ, UK
5State Key Laboratory of Continental Dynamics and Department of Geology, Northwest University, Xi’an 710069, People’s Republic of China
6Graduate School of Advanced Science and Technology, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa, 923-1292, Japan
7School of Earth and Space Sciences, Peking University, Beijing 100871, People’s Republic of China
8CAS Center for Excellence in Comparative Planetology, Hefei, 230022, People’s Republic of China

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Sound velocities in lunar mantle aggregates at simultaneous high pressures and temperatures: Implications for the presence of garnet in the deep lunar interior

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Marisa C. Wood1, Steeve Gréaux1, Yoshio Kono1, Sho Kakizaw1,2, Yuta Ishikawa1, Sayako Inoué1, Hideharu Kuwahara1, Yuji Higo2, Noriyoshi Tsujino2, Tetsuo Irifune1
Earth and Planetary Science Letters 641, 118792
Link to Article [https://doi.org/10.1016/j.epsl.2024.118792]
1Geodynamics Research Center, Ehime University, Matsuyama, Japan
2Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo, Japan
Copyright Elsevier

Recent experimental and theoretical studies on lunar magma ocean crystallisation have suggested the presence of significant proportions of garnet in the deep lunar interior. While phase relation studies indicate a deep lunar mantle consisting of olivine, pyroxene, and garnet, the compatibility of such an assemblage with seismic models of the lunar interior is yet untested. In this study we report compressional and shear wave velocities in an iron-rich assemblage consisting of olivine, orthopyroxene, clinopyroxene, and garnet up to ∼8 GPa and 1300 K, by means of ultrasonic interferometry measurements combined with synchrotron techniques using the multi-anvil press apparatus. Sound velocity and density models of lunar mantle rocks along a selenotherm based on our experimental results find good agreement with the seismic and density profiles at lunar interior depths of 740–1260 km. Further models are constructed, allowing for the variation of chemical composition, phase proportion, and temperature; these suggest that a garnet-rich deep lunar mantle is compatible with present-day lower lunar mantle temperatures of between 1400–1800 K. Our results show that lunar mantle rocks with up to 33 wt.% garnet may provide an explanation for the observed high velocities of the lower lunar mantle. The presence of garnet in the lowermost part of the Moon’s mantle has significant implications for the depth and temperature of the Moon’s magma ocean as well as the composition, structure and internal dynamics of the solid Moon.