地幔柱数值模拟研究进展

国外大量的数值模拟研究表明地幔柱由热浮力驱动,流体的黏度对地幔柱的形状和物质组成有着很大的影响,地幔柱可造成岩石圈的熔蚀减薄和地表隆升,数值模拟可以定量地得出地幔柱运动的速度、岩石圈的熔融量和熔融温度等要素,但这些模拟描述的仅是物理过程,缺乏与化学动力学相耦合.国内开发的可对峨眉地幔柱进行数值模拟的软件MantlePlume1.0也存在许多需要进一步研究解决的问题,如峨眉山玄武岩的物质来源、活动中心、喷发时限、喷发规模、岩石圈的隆升程度,以及峨眉地幔柱的温压条件和断裂构造形成机理等.

Advances in the Numerical Simulation of the Mantle Plume

Numerical simulation is an important method in the research of mantle plume. The math model consists of density and continuity equation, momentum conservation equation and energy conservation e-quation mainly. Many researches by numerical simulation overseas showed that mantle plume is driven by thermal buoyancy. While the fluid viscosity is crucially responsible for the shape and composition of the mantle plume. As the mantle plume can cause the thinning, thermal corrosion and surface elevation, it is possible to calculate quantatively the velocity of the plume movement,melting volume and melting temperature in lithosphere. But these researches without focus on physical processes, without coupling with chemical dynamics. In China, Li Jiankang has developed software-MantlePlumel. 0,and carried out a preliminary research on E'mei mantle plume. Although in this research some basic problems are solved, many problem remained to be resolved by advanced numerical simulation. These problems include the forming mechanism of E'mei plume, the basalt magma source of the basalt, the active center of basalt magma eruption, the time limitation of basalt magma eruption, the scale of the basalt magma eruption, the swelling and denuding level of lithosphere, temperature and pressure of the E'mei plume, and the forming mechanism of ruptures in the volcanic province.