Abstract: Mylonite,cataclasite and especially fault rocks subjected to both mylonitization and cata-clasis widely developed along the Kangding-Moxi fault zone.A mylonite zone has formed as a result of ductile shearing in early stage.In later stage brittle fracturing has occurred along this mylonite zone,accompanied by the formation of the present Kangding-Moxi fault zone.Later on,ductile shearing and multiperiods of brittle fracturing occurred along the fault zone.Differential stress magnitude during the early faulting process was 50 MPa,as determined by using microstructural piezometer,while that for the late stage was 30 MPa.The activity of the fault zone tends to be weaker,i.e.from high to low stress level.

Key words: Microstructures, Mylonite, Cataclasite, Differential stress. Fault activity, Kangding-Moxi fault zone

摘要： 根据野外考察和显微构造分析可知,沿康定-磨西断裂带出露有碎裂岩和糜棱岩,最主要的是叠加有碎裂和糜棱岩化两种作用的断层岩。断层带经历过韧性～脆性～韧性～脆性的多类型,多期次的活动,活动性质有左旋错动,也有右旋剪切,而脆性断裂以左旋为主。较早期断裂活动时的差应力为50MPa,属于中高应力状态;到晚期活动时,差应力有所降低,约为30MPa。

关键词: 糜棱岩, 碎裂岩, 显微构造, 差应力, 断层活动, 康定-磨西断裂带