中缅泰交界区的断裂及其新构造活动方式

安达曼海裂谷的张开和印度板块与欧亚板块碰撞,青藏高原大幅度隆起派生的向南偏东的推挤,导致中缅泰交界区的南北向断裂新构造活动方式为右行走滑且自西向东规模变小;还产生一组近北东东向的断裂向南作叠瓦状逆推,伴有左行走滑,向南规模变小。这些断裂控制了盆地、水系、温泉、火山(岩)的发育,沿之有地震发生。

FRACTURES AND THEIR NEOTECTONIC ACTIVE MODES IN BORDER AREA OF CHINA,BURMA AND THAILAND

There are two fracture systems in the border area of China,Burma and Thailand duringlate Neogene—Quaternary.The S-N fractures,such as Sagaing,Nujiang and LancangjiangFractures,are dextral.The approximate NEE system stretches along W-E direction in Burma,turning eastward to NEE and NE in Yunnan,China.Most of the fractures,for example,Hsenwi-Nandinghe,Ke-shi Mansam-Menglian and Kengtung-Daluo Fractures,are oblique(sinistral) thrusts.Some of them,such as Ximeng Fracture and fracture in east of Lampang,N-dipping gently,result in the upper wall overthrusted southwards,even nappe outliers form-ed.In some positions occur the NW fractures,for instance,Heihe and Zhen’an Fractures,which are conjugate faults of the approximate NEE system.The S-N and approximate NEEfractures,NW fractures as well,control the lignite (or peat) -bearing basins,drainages,hotsprings (or geothermal fields),volcanoes,etc.,and earthquakes take place along these frac-tures.