月球早期阶段为岩浆洋阶段，岩浆洋的研究对认识月球内部构造，指示月球和行星起源有着重要意义。月球岩浆洋演化主导模型认为：岩浆洋结晶到80%左右，斜长石开始结晶上浮形成斜长岩月壳，整个岩浆洋在几个Ma时间内固化。同位素体系对月球岩石样品定年结果表明月壳的结晶年龄十分古老，并且结晶区间跨越了270Ma，这与主导模型之间存在矛盾。为了解决这一矛盾，我们拟将硅酸盐岩浆在温度梯度下的热扩散效应引入岩浆洋演化模型。热扩散效应指均一的物质在温度梯度下发生分异的过程。本项目工作模型是：岩浆洋自上而下存在温度梯度，岩浆洋在该梯度下发生热扩散效应，岩浆洋在成分上是分异的，月壳是上部部分结晶区结晶形成的。为了定量化计算该模型，本项目拟采用高温高压实验研究硅酸盐在温度梯度下的热扩散性质，并通过使用MELTS和MATLAB等软件模拟计算岩浆洋在温度梯度下的演化，最终提出岩浆洋分异演化和月壳成因模型。

The early state of the Moon is thought to be Lunar Magma Ocean (LMO). Studies of LMO not only have significant meaning for recognizing the internal structure of the Moon, but also can be indicative for the origin of the Moon and planets. The dominated model of the LMO suggest that after 80% of the LMO solidified, plagioclase starts to crystallize and floats to the surface to form anorthositic crust and the whole solidifying time for the LMO is only several million years. The dominated model has discrepancy with the Apollo observations that crystallization ages of anorthosites span 270 Ma. To solve this problem, we focus on the temperature gradient in the LMO and apply mass transport under thermal gradient to its evolution. Chemical heterogeneity can occur in the initially homogenous silicate melt under thermal gradient, which is named thermal diffusion. Our working model is: the LMO is stratified in the composition, and the lunar crust is formed from the upper part. In order to quantify our model, we plan to design High-Temperature-High-Pressure experiments and do numerical simulations. Based on these results, we would propose a new model of lunar magma ocean evolution under thermal gradient and crust formation.