燕山地区密云—喜峰口断裂的东延问题探讨

A Discussion on Eastward Extension of the Miyun—Xifengkou Fault

密云—喜峰口断裂是燕山地区一条重要的近东西向断裂。前人关于该断裂在几何学形态、运动学机制等方面进行了大量研究并取得了许多重要成果。但关于该断裂到喜峰口后往东延伸的问题存在重大分歧。在延伸方向上主要有两种观点:①继续向东延伸,其整体呈近东西向展布;②转为北东向延伸,其整体呈向南东突出的弧形断裂。在具体延伸途径和延伸距离方面每种观点都存在不同的意见。本文以航磁资料为基础,结合地质与卫星遥感影像资料,综合分析认为密云—喜峰口断裂具有明显的分段性,密云—喜峰口段呈近东西向展布;自喜峰口往东转为北东向延伸,经宽城县东大地、亮甲台,一直延伸到汤道河附近,其整体为呈向南东突出的弧形断裂。

Many important geometry and kinematics mechanism results about the Miyun—Xifengkou fault, which is an important east—west fault in the Yanshan area, have been achieved, but a significant divergence still exists in how the fault extend after arrived Xifengkou area. One view is that the eastward of the fault is consistently E—W and the whole fault is from west to east; the other view is that the extending towards northeast and the whole fault is a southeast protruding arcuate fault. There are different opinions on the problems of extension way and extending distance for each of the views. In this paper, one conclusion is obtained by analysing the aeromagnetic data and refering to the supplementary geological and satellite remote sensing image data that the Miyun—Xifengkou fault is obviously divided into two sections. The west section is from Miyun to Xifengkou, whose direction is from west to east; the other section is on the east of Xifengkou, which extends toward northeast and arrives at Tangdaohe (Kuancheng county) via Dongdadi (Kuancheng county) and Liangjiatai (Kuancheng county), and it is a southeast protruding arcuate fault in the whole.