2017 Fiscal Year Final Research Report
Asymmetric Crystallization of the Lunar Magma Ocean
| Project/Area Number |
16K17790
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Solid earth and planetary physics
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2018-03-31
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| Keywords | moon / planetary science / magma / ocean |
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| Outline of Final Research Achievements |
The purpose of the research was to investigate the origin of the asymmetry in the lunar crust. In particular, the ratio of Mg to Fe (Mg#) varies longitudinally. As Fe fractionates to the liquid phase as the primordial magma ocean crystallizes, we wanted to test if that longitudinal variation could be due to an asymmetric crystallization of the lunar crust.
The main driver of this asymmetry could be the influence of a magma ocean on the early Earth, while the Moon's orbit was closer. We used such a thermal forcing as a boundary condition to an energy balance calculation to estimate crustal growth rate on each lunar hemisphere and predict Mg# variation with depth. Then, we developed a basin impact model to characterize the degree of mixing of the lunar crust during its early evolution, as what is observed today from satellite observation is the result of the long-term mixing of the upper crust. We found that this scenario is able to explain the Mg# longitudinal variation.
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| Free Research Field |
Planetary science
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