2023 Fiscal Year Research-status Report
Experimental constraints on the structure and composition of the lunar interior by elastic wave velocity measurement at high pressure and high tempreature conditions
| Project/Area Number |
23KF0261
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| Research Institution | Ehime University |
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Principal Investigator |
GREAUX Steeve 愛媛大学, 地球深部ダイナミクス研究センター, 助教 (90543166)
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| Co-Investigator(Kenkyū-buntansha) |
JING JIEJUN 愛媛大学, 地球深部ダイナミクス研究センター, 外国人特別研究員
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| Project Period (FY) |
2023-11-15 – 2026-03-31
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| Keywords | lunar mantle / high pressure / ultrasonic measurement / garnet |
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| Outline of Annual Research Achievements |
In order to measure the sound velocity of lunar minerals in SPring-8, lunar garnet aggregates were synthesized at Ehime University. In this FY, a side research to this proposal has been published as Jing et al. (2024) titled ‘Experimental investigation of first-row transition elements partitioning between olivine and silicate melt: Implications for lunar basalt formation.’ This research revealed the possible existence of iron grains in the lunar mantle, providing insights into the lunar mantle composition. The possible existence of iron metal offers an extra chance for studying sound velocity of iron-bearing, garnet-bearing lunar aggregates, further extending the main goal of the current project.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The progress of this research project is steadily ongoing, and no unforeseen events have happened so far. During this fiscal year since last December the project started, a proposal submitted to SPring-8 was granted beamtime in May and June 2024 to conduct ultrasonic sound velocity measurement on lunar garnet. Thus, the main progress in this period is the preparation for synchrotron experiments before the end of May, 2024. Several polycrystalline lunar garnet samples were synthesized and prepared for synchrotron experiments.
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| Strategy for Future Research Activity |
In May and June, 2024, ultrasonic sound velocity measurements will be carried out the synthesized garnet samples. Based on the results, further ultrasonic measurements on garnet with different compositions will be discussed. Alternatively, we plan to investigate the sound velocities of lunar ilmenite or both. The lunar ilmenite is believed to have formed at the topmost lunar mantle but sank into the lower mantle. Thus, both the garnet and ilmenite are crucial constituents in the lunar mantle. The knowledge of their ultrasonic sound velocity is important for unraveling the lunar mantle structure and composition.
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| Causes of Carryover |
Due to unforeseen circumstances and the limited time between the start of this project and the end of the FY (e.g. December 2023 to March 2024), we could not proceed all expenses as initially planned.
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| Remarks |
Received the John C. Jamieson Student Paper Award. 2023 December. American Geophysical Union.
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