上地幔变黏度小尺度对流的数值研究  

A NUMERICAL RESEARCH ON THE SMALL-SCALE CONVECTION WITH VARIABLE VISCOSITY IN THE UPPER MANTLE

作　　者：叶正仁[1] 王建[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029

出　　处：《地球物理学报》2003年第3期335-339,共5页Chinese Journal of Geophysics

基　　金：国家自然科学基金 ( 499740 2 2 );中国科学院知识创新工程项目 (KZCX2 -112 ) .

摘　　要：基于二维模型 ,利用有限元方法 ,研究上地幔 -岩石圈系统的变黏度小尺度对流 .考虑该系统的黏度随温度以指数形式变化 ,数值结果表明 ,当黏度随温度变化较剧烈时 ,由于低温高黏度 ,系统的最上部物质不参与对流 ,系统发育形成一个类似于岩石圈的静止盖层 .计算表面热流、地形起伏及重力异常与对流格局有较好的相关性 ,高热流、上升地形对应于对流的上升区 ,反之低热流、下降地形与对流的下降区对应 .Based on a two-dimensional model, small-scale convection in the upper mantle-lithosphere system with variable viscosity is researched by using finite element method. Variation of viscosity in exponential form with temperature is considered in this paper. The results show that if viscosity is strongly temperature-dependent, the upper part of the system does not take a share in the convection and forms into a stagnant lid similar to lithosphere because of low temperature and high viscosity. The calculated surface heat flow, the topography and the gravity anomalies are associated well with the convection pattern, namely, the regions with high heat flow and uplift correspond to the upwelling flow, and vice versa.

关 键 词：小尺度对流 有限元方法 静止盖层 热流 黏度 

分 类 号：P314.2[天文地球—固体地球物理学]