西南三江构造带及扬子西缘前寒武纪基底岩群与构造演化

THE PRE-∈ BASEMENT ROCK GROUP AND STRUCTURAL EVOLUTON IN THE SW SANJLANG STRUCTURAL ZONE AND THE WEST MARGIN OF YANGZI PLATFORM

西南三江构造带及扬子西缘在前寒纪时期，或者说元古宙时期，只有两个在形式上有联系的构造区，它们的基底岩群和构造演化都不尽相同。当时的欧亚大陆虽大致在现今位置，而冈瓦纳大陆尚在赤道附近，并且是“内部分隔”的微大陆。因而，地理上的“西南三江”当时明显地分割为东、西两部份；现代则划分为三部份，其中应突出北羌塘－澜沧江及拉竹龙－金沙江－藤条江两构造带之间的唐古拉－昌都－兰坪－思茅过渡带或转换（化）带的存在事实。

In Pre-Cambrian or Proterozoic,there were two structural areas in the Sanjiang structural zone of SW China and the west margin of Yangzi platform,which are related in the form but different in their basement rock group and structural evolution. At that time,the position of Eurasia was almost the same as today, but Gondwana was near the equator and was an 'internal separation' microcontinent then. Therefore,the ' SW Sanjlang' in geography was distinctly divided into E,W two parts at that tine.Today, it can be divided into three zones.And we must emphasis the exist of the Tanggula-Changdu-Lanping-Simao transition or transformation zone between the N Qiangtang-Lancang River and the Lazhulong-Jinsha River-Tengtiao River two structural zones.