大巴山弧形断裂(镇巴-高川段)的磁性特征及构造意义  

Magnetic anomaly analysis of the Dabashan arc fault and its tectonic implications

作　　者：张燕[1,2] 董云鹏[1] 李同国 杨明生 程顺有[1] 王永平 

机构地区：[1]西北大学大陆动力学国家重点实验室,地质学系,西安710069 [2]陕西省地质矿产勘查开发局第二综合物探大队,西安710016 [3]山东烟台武宁水利站,烟台264118

出　　处：《地球物理学进展》2009年第4期1267-1274,共8页Progress in Geophysics

基　　金：中国地质调查局矿调项目资助

摘　　要：秦巴山区的大巴山断裂(镇巴-高川段)及周边地区实施了高精度磁力勘探,经过向上解析延拓、垂向不同阶导数及欧拉反褶积等新方法处理及其分析,结果表明研究区磁场特征具有明显的规律性:横向上分别显示出沉积区、挤压构造变形区及侵入岩区的磁性特征,这是研究区多样化构造特征的具体反映;纵向上,浅部磁场呈现方向性磁场,深部呈现稳定基底的特征,这种磁性差异分界面构成了北大巴山地区逆冲推覆构造的滑脱面.而大巴山主断裂在不同区段表现出不同磁性结构的多样化特征,也反映了不同挤压应力作用下变质程度的差异.The data of high-precision magnetic exploration in the area of the Dabashan fault and the surroundings was processed by the upward continuation,vertical derivation of different orders and Euler method for delineating magnetic boundaries. We present the characteristics of magnetic anomalies of field sources at different depths and their tectonic implications. In the horizontal direction it shows the magnetic characteristics of sediment trap, squeeze deformation and metamorphic zone, intruded rock, which is representation of diverse tectonic features mentioned above. Vertically the shallow magnetic field displays the directive magnetic field, and the depth portion presents the characteristics of stable basement. This difference in the magnetic interface constitutes a thrust structure of the detachment surface in the northern Dabashan. And diversified characteristics of the Bashan main fault that has different magnetic structure in different sections represent the metamorphic tectonic response to the different compressional stresses.

关 键 词：大巴山弧形断裂 磁异常 向上延拓 构造特征 

分 类 号：P313[天文地球—固体地球物理学] P318[天文地球—地球物理学]