Abstract: The Xianshuihe fault zone is a well known active fault located at the north eastern boundary of the Tibetan plate. The micro texture and microstructures of fault gouge, the eroded micro texture and microstructures on the surface of quartz fragments from the fault zone are measured by Scanning Electron Microscope. The results of statistics and analysis show that the fault zone has experienced the intense oriented stress field and displays the stick slip movement mode. Its activity was still continuing from late Pleistocene to Holocene. Both the feature of the grain size distribution from fault gouge and the analysis of the fractal dimension have the obvious segmentation along the fault zone. This is consistent with the result from geodetic surveying along the fault zone in recent years.

Key words: Xianshuihe fault, Fault gouge, Microstructure, Fractal, Fault segmentation

摘要： 对鲜水河断裂的断层泥样品进行原样的结构、构造和碎砾的显微构造、刻蚀形貌结构的观测统计,断层泥的粒度分析和分形研究,认为,断裂处于强烈的定向应力场作用之下,其运动方式是以粘滑运动为主,且晚更新世和全新世时期断裂仍有活动。从断层泥的粒度分布和分形分析可将断层分为:甘孜-格篓、格篓-恰叫、恰叫-乾宁3段,这与前人的地形变分析的分段结果相一致。

关键词: 鲜水河断裂, 断层泥, 显微构造, 分形, 断层分段