宁波地区镇海断裂带燕山晚期构造应力场研究

A STUDY ON THE LATE YANSHANIAN TECTONIC STRESS FIELD NEAR ZHENHAI FRACTURE BELT IN NINGBO AREA

镇海断裂带形成于燕山晚期,是宁波地区主要的构造带。本文在对镇海断裂带构造变形特征研究的基础上,利用断裂带的共轭节理、断层擦痕和显微构造的综合分析,定量地确定了镇海断裂带燕山晚期构造应力场的主应力方位;同时利用岩石破裂理论、方解石e双晶页理和石英的位错密度,半定量地估算燕山晚期构造应力场的差异应力,获得了可信的结论。

Zhenhai fracture belt formed in the Late Yanshanian tectonic movement, It is the major tectonic belt in Ningbo area. On the basis of field observations, stru-ctural deformation analysis in Zhenhai fracture belt,in terms of striation measure-ment on fault planes, analysis of conjugate joints and microstructures near the fracture belt,the stress direction of the Late Yanshanian stress fields is determin-ed. In the meantime, According to the rock fracturing theory, and the calcite twin lamellae and dislocation density in the deformed quartz, the differential str-ess is estimated.