一、前言云南西部澜沧江变质带,主要由北部的崇山群,西部的勐统群以及南部的澜沧群组成。在云南境内长约七百公里,北部基本上沿澜沧江分布,南部展布于澜沧江西侧。南段的澜沧群,分布在云县、澜沧、勐海至国境线一带,据范承钧的意见,在区域构造上,属于澜沧江哀牢山褶皱带的一部分,次一级构造单元为临沧—澜沧复背斜,其西 I. Preface The Lancangjiang metamorphic belt in western Yunnan mainly consists of the Chongshan Group in the north, the Meng Tong Group in the west and the Lancang Group in the south. It is about 700 kilometers long in Yunnan Province, with its northern part basically distributed along the Lancang River and its southern part at the west side of the Lancang River. According to Fan Chengjun’s opinion, on the regional tectonics, it belongs to the part of Ailaoshan fold belt in the Lancang River, and the secondary tectonic units are Lincang, Lancang and Menghai. - Lancang complex anticline, the west