Abstract: Sructural joints and gouges of the main fault zones in Northern North China were determined,statistically studied and analysed on micro-computer and scanning electron microscopy(SEM). Only twenty percents of the structural joints are oriented in the direction favorable to activation in the effect of the present stress field. Most of these structural joints were formed in the local stress field associated with the formation of the fault zones. The statistical study of rnicro-textures on the surface of quartz fragments from the fault gouges on SEM gives the last activity time of these fault zones, and the SEM determination of microstructures provides some information on the movernent mode along these fault zones. The results of these methods will provide more evidence for the fault activity.

Key words: North China, Structural joint, Stress orientation, Microstructure, Fault activity time, Movement mode of fault

摘要： Sructural joints and gouges of the main fault zones in Northern North China were determined,statistically studied and analysed on micro-computer and scanning electron microscopy(SEM). Only twenty percents of the structural joints are oriented in the direction favorable to activation in the effect of the present stress field. Most of these structural joints were formed in the local stress field associated with the formation of the fault zones. The statistical study of rnicro-textures on the surface of quartz fragments from the fault gouges on SEM gives the last activity time of these fault zones, and the SEM determination of microstructures provides some information on the movernent mode along these fault zones. The results of these methods will provide more evidence for the fault activity.

关键词: North China, Structural joint, Stress orientation, Microstructure, Fault activity time, Movement mode of fault