Advances in experimental petrology study on the evolution of the lunar magma ocean

Due to the lack of rock samples directly from the deep part of the Moon, experiments and numerical simulation are effective methods to understand the early evolution of the Moon. Since the 1970s, the Lunar Magma Ocean (LMO) evolution model has been verified and modified by a large number of experimental petrology and geochemical work. However, the original composition of the Moon and the depth of its magma ocean, which are the two most critical parameters of LMO models remain controversial. The different lunar crust thickness estimated from lunar seismic data compared to that estimated from gravity data, the volatile content of lunar samples, and the widespread of Mg and Al-rich spinet (Cr (#) <5) discovered from interpreting the new remote sensing data affect our assessment on the starting composition and the depth of LMO, and the fractional crystallization process thereafter. In this paper, we review a series of high temperature and high pressure experimental petrology and experimental geochemistry results on the Moon's early evolution by focusing on: (1) The influence of refractory elements and volatile content of LMO's composition and its depth on the thickness of lunar crust and the Moon's mineral constitution formed through early differentiation. (2) The rationality of stability of high pressure mineral garnet deep inside lunar mantle and it effect on the distribution of trace elements during the evolution of lunar. (3) The petrogenesis of the Moon's special components, including volcanic glasses and Mg-suite, and their indication on the composition of the Moon's deep interior. (4) The constraint of lunar core composition on the Moon's material source, especially the abundance of trace elements. Based on the latest observation and the new analysis results of lunar samples, we evaluate the existing LMO evolution models and propose a LMO model with garnet as an important constituent mineral inside the Moon. We also discuss the necessary work need to be done to improve the "new" LMO model.