河北阳原侯家窑断层的几何学与运动学及动力学

GEOMETRY,KINEMATICS AND DYNAMICS OF THE HOUJIAYAO FAULT IN YANGYUAN COUNTY,HEBEI

侯家窑断层是阳原盆地西缘一条区域性正断层,它切割了部分第四纪沉积层,并被马兰黄土所覆盖。具多期次活动的特征,遗留下了丰富的伴生、派生构造形迹。在野外详细观测断层的几何学特征、分析运动学标志的基础上,结合前人研究成果,认为发生了三期构造活动:第一期为区域性拉伸;第二期为短时间区域性挤压;第三期是区域性隆拗。其动力学机制分别为张宣幔枝隆升作用、太平洋板块俯冲的远程效应和汾渭裂谷深部过程控制的断陷-隆升效应。恢复了阳原盆地演化过程:区域性总体快速隆起→构造反转形成裂陷→裂陷加深形成地堑→导致基性岩浆活动→形成区域裂陷地幔底垫→裂谷盆地逐渐形成→构成生物快速演化的一系列构造激变→生态繁衍的大循环系统。

The Houjiayao fault is a regional normal fault along the west border of the Yangyuan basin,which cuts through a part of the Quaternary and is covered by the Malan loess.It is characterized by a variety of associated and derived structural features and multi-periodical activities.Based on the geometric features and kinematic marks of the fault structures in the field and previous studies,there recognized three stages of tectonic activities.The first stage was suffered from a regional tension,the second stage from a short time regional extrusion and the third stage from a regional uplifting and depression.With regard to the dynamic mechanism,the activities of the fault were obviously droved by the uplifting of the Zhang-xuan mantle branch,the remote effect of the subduction of the Pacific plate and the deep process of rifting and-uplifting of the Fenwei rift.The evolution of the Yangyuan basin is reconstructed.It started from regional and rapid uplifting as a whole,then followed by further rifting of tectonic inversion-formed graben-mafic magmatic activities-formation of regional rifting mantle mat- gradual formation of the rift basin-a series of tectonic changes and a large circulation system for biological breeding.