南北构造带中段的壳幔结构与岩石圈动力学特征

本文利用WDM—89地球重力模型(完整到180阶)的位系数计算了南北构造带中段的30—50阶、50—100阶、100—150阶、150—180阶及2—180阶卫星重力异常,并探讨了该区的壳幔结构。结果表明,该区上地幔存在一个规模较大的低密度区。若尔盖和雅江一带有两个底部相连的高密度地幔块体。该区壳幔结构不但横向很不均匀,而且纵向也极为复杂。据此对区域岩石圈动力学特征进行了讨论。

STRUCTURE OF THE CRUST AND UPPER MANTLE AND FEATURE OF LITHOSPHERIC GEODYNAMICS IN THE N--S TECTONIC BELT (MIDDEL PART)

In this paper, the satellite gravity anomalies of 30--50,50--100,100--150,150--180 and 2--180 degrees are computed in the N-S tectonic belt (middle part) by use of the coefficients of WDM--89 earth gravity model (to 180 degrees). The structure in the crust and upper mantle is also analysed. The results show that there exists a large zone of low density in the upper mantle. In Ruoergaiand Yajiang there are two high-denstiy mantle blocks whose bottoms connect. The structure in the crust and upper mantle is not only inhomogeneous laterally, but complicated vertically. Moreover,the Lithospheric geodynamics in the zone is discussed.