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.

Lunar volcanic glasses associated with mare basalt magmatism experienced significant degree of degassing, and to retrieve their initial water contents requires data of water diffusivity. We carried out diffusion experiments at 0.5 GPa and 1703-1903 K in a piston cylinder apparatus for two synthesized lunar basaltic melts with compositions corresponding to Apollo green glass and yellow glass. The water diffusion profiles measured by FTIR spectroscopy yield water diffusivities 0.5-1 order of magnitude greater than those of terrestrial basaltic melts, which is attributed to the difference in melt polymerization and modest contribution from H-2 diffusion. However, hydroxyl (OH) is not only the dominant H species but is also inferred to be the major carrier of H in our experiments at oxygen fugacity estimated IW +/- 1 (IW: iron-wustite buffer). Modeling of previously reported profiles of volatile loss in an Apollo green glass bead using the new water diffusivity indicates an average cooling rate of 1-2 degrees C/s and an initial water content of 120-260 mu g/g. With the assumption of limited degassing before magma fragmentation, the lunar mantle source is inferred to contain 6-22 mu g/g H2O. The lunar interior appears to be less hydrous the Earth's interior but still contains a considerable amount of water. (C) 2019 Elsevier B.V. All rights reserved.

We report the solubility of water in Apollo 15 basaltic Yellow Glass and an iron-free basaltic analog composition at 1 atm and 1350 degrees C. We equilibrated melts in a 1-atm furnace with flowing H-2/CO2 gas mixtures that spanned similar to 8 orders of magnitude in fO(2) (from three orders of magnitude more reducing than the iron-wustite buffer, IW - 3.0, to IW 14.8) and similar to 4 orders of magnitude in pH(2)/pH(2)O (from 0.003 to 24). Based on Fourier transform infrared spectroscopy (FTIR), our quenched experimental glasses contain 69-425 ppm total water (by weight). Our results demonstrate that under the conditions of our experiments: (1) hydroxyl is the only H-bearing species detected by FTIR; (2) the solubility of water is proportional to the square root of pH(2)O in the furnace atmosphere and is independent of fO(2) and pH(2)/pH(2)O; (3) the solubility of water is very similar in both melt compositions; (4) the concentration of H-2 in our iron-free experiments is similar to 200 ppm C would be required for the vapor composition to be dominated by CO rather than H-2 at 65-75% vesicularity. (C) 2016 Elsevier Ltd. All rights reserved.