5.1.5 Lunar mantle fragments at the surface
The SELENE mission was a Japanese lunar orbiter, launched 14 September 2007. The scientific objectives included obtaining information about the chemical composition of the lunar surface and studying the formation and geological evolution of the Moon. You will learn more about the SELENE mission next week.
The spacecraft measured the reflectance spectra of the lunar surface over a broad range of wavelengths and with a spatial resolution of around 500 m, in order to map the global distribution of the mineral olivine. The magma ocean hypothesis predicts that the mineral olivine should dominate the upper mantle and therefore should not be common in the lunar highlands. However, 34 olivine-rich sites were identified and all were concentrated around large impact basins located in thinner parts of the lunar crust. The presence of olivine is believed to be a result of exhumation of upper mantle material during large impacts, suggesting that olivine does occur in the upper mantle. No olivine was found in the thicker highlands crust.