Details

Autor(en) / Beteiligte

• Wood, Marisa C.
• Gréaux, Steeve
• Kono, Yoshio
• Kakizawa, Sho
• Ishikawa, Yuta
• Inoué, Sayako
• Kuwahara, Hideharu
• Higo, Yuji
• Tsujino, Noriyoshi
• Irifune, Tetsuo

Titel

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

Ist Teil von

• Earth and planetary science letters, 2024-09, Vol.641, p.118792, Article 118792

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2024

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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. •In situ ultrasonic interferometry measurements carried out in the multi-anvil press.•Sound velocities in a garnet-rich assemblage were determined up to 8 GPa and 1300 K.•Temperature and chemical composition were varied via elasticity and density models.•Our results were interpreted via with lunar seismic profiles.•These results support the presence of up to 33 wt.% garnet in the lower lunar mantle.