卫星重力场、地幔对流应力场与板块运动关系的探讨

A STUDY ON THE RELATION BETWEEN SATELLITE GRAVITY ANOMALIES MANTLE CONVECTION STRESS AND MODERN PLATES MOVEMENT

本文采用GEM10C的前50阶系数,计算了全球自由空气重力异常和地幔对流产生的岩石层底部应力场.通过对全球重力异常、应力场的分析,着重讨论了板块运动与地幔对流间的关系.对各板块在地幔对流作用下受力的定性分析和定量计算表明,板块的运动主要由低阶应力场决定,板块底部多个地幔对流体(而不是一个以洋中脊为对流上涌中心的单个地幔对流)的共同作用,推动了现代板块的运动.

In this paper, the 2-50 degree harmonic coefficients of GEM10C have been used to calculate the global gravity anomalies and the global stress field caused by the mantle convection currents under lithosphere. Through analysising global gravity anomalies and stress field, the realation between the plate motion and mantle convections has been discussed. The calculation of the average force per square unit of plates under lithosphere caused by the mantle convection currents in-dcates that the movement of the modern plates is mainly determinated by low degree (2-12) stress and usually several mantle convection currents (not the only one beneath the oceanic ridge) under plates drive the modern plates.