滇西试验场区三维重力反演研究

THREE DIMENSIONAL INVERSION OF GRAVITY ANOMALIES IN THE WESTERN YUNNAN

本文依最新获得的滇西试验场区布格重力异常成果和近几年该区已有的人工地震测深资料，利用Ｐａｒｋｅｒ－Ｏｌｄｅｎｂｕｒｇ快速位场反演方法和文献［１］设计的反演计算程序，实施了多个密度界面的三维重力反演，首次获得了该区地壳上、中、下三界面的整体展布图像，分析了它们的细化结构，并结合本区重力异常特征讨论了界面图像的构造物理意义，结果表明：区内杨子板块地壳界面的去耦滑动远强于三江微板块，洱源—永胜一线的地壳半细颈结构是区内现代构造运动最活跃的地段。

Based on a new map of complete Bougure gravity anomlies and recent results of deep seismic souding with explosion in the Western Yunnan, crustal structure of deep interfaces is studied using the Parker-Oldenburg's formula of rapid inversion of potential field and the methods of decomposition,resularization,layer by layer inverslon from bottom to top.It is first obtained that depth distribution of density interfaces between the upper,middle and lower curstal show complete image detailed.In this paper,some tectonophysics significance of the interface image together with Bougure and isostatic gravity anomalies is discussed.It is indicated that in the resion,decoupling interface slip of the Yangtze plate is far greater than that of the Sanjiang microplate,and crustal semi-necking structure along the Eryuan-Yongsheng is a very active zone of recent structure movement.