恩梅开江断裂特征与活动性研究

Study on characteristics and activity of Nmai Hka River Fault

恩梅开江断裂北起中国西藏波密附近,往南经西藏日东,沿云南贡山的独龙江下游至马库附近以南北向延伸进入缅甸境内,沿恩梅开江左岸岸坡附近一线展布,全长约335 km。研究表明,该断裂带是一条重要的沉积、变质、岩浆活动和构造的控制带,断裂早期为一条韧性剪切带,宽度大于百米,后期又有脆性变形,表现为发育多条宽度不一的脆性破裂带。通过对地形地貌特征、断裂上覆新沉积物变形特征、断裂物质及上覆沉积物测年、断裂沿线地震活动性等研究表明,该断裂为早、中更新世断裂。就该断裂活动性的研究,对于弄清区域内其他断裂的活动性具有重要借鉴作用。

The northern part of Nmai Hka River Fault starts at Bomi,Tibet,goes south to Ridong of Tibet,and then extends along the downstream Dulong River and enters into Burma at Maku of Gongshan mountain.It mainly extends along left bank slope of Nmai Hka River,which is 335 km in total.The study indicates that the fault is an important control fault for deposit,metamorphic,magma activity and structure movement.In early ages,it was a tough shear rupture zone with the width larger than 100 m,and later it had brittle fracture that was manifested as several brittle rupture zones with different widths.By comprehensive analysis of topography and geomorphology,deformation features of new overlying deposits,dating of fracture material and overlying deposit and seismic activity along the fault,this fault was determined as an Early-mid Pleistocene fault.