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本文所指滇西地区,除三江褶皱系南部外,尚包括1:400万中国大地构造图所划的冈底斯——念青唐古拉褶皱系南部在云南省境的部分,以及松潘——甘孜褶皱系中的玉树——义敦褶皱带南部。本区构造特点是二、三级构造单元常以深断裂为界。二、三级甚至四级构造单元具有各自不同的发展史。深断裂伴随构造变质,多数有混合岩化作用,少数出现高压变质矿物或混杂堆积,超基性岩也出现于构造变质带间,因此滇西地区可能处于多次板块汇聚部位。要阐述滇西地区的区域地质特征,需根据二、三级构造单元的特点加以讨论。本文提出并讨论了:一、澜沧江深断裂以西古微大陆的存在,并分澜沧江古缝合线、昌宁——澜沧弧后隆起带、保山弧后盆地加以讨论;二、高黎贡山——潞西变质带;三、波密——腾冲山弧带;四、兰坪——思茅中生代拗陷盆地,分别对拗陷基底、中生代拗陷的性质、地堑盆地的演化及堑沟的形成等问题作了论述;五、哀牢山变质带的性质;六、义敦——中甸岛弧带。
In addition to the southern part of the Sanjiang fold system, the western part of Yunnan refers to the part of southern Gangdese-Nyainqentanglá fold in Yunnan Province designated by the 1: 4 million tectonic map of China and the Songpan-Garze Yushu in the folds - south of the Yidun fold belt. The tectonic features of this area are that the second and third tectonic units are often characterized by deep faults. Two, three or even four tectonic units have their own different development history. Deep faults are accompanied by tectonic metamorphism, most of them are migmatite, and a few of them occur high-pressure metamorphic minerals or mixed deposits. Ultramafic rocks also occur in the tectonic metamorphic belt, so the western Yunnan may be in a multi-plate convergence area. To elaborate the regional geological features in western Yunnan, it is necessary to discuss the characteristics of the second and third tectonic units. This paper presents and discusses the following aspects: (1) The existence of the paleoceanic continent west of the deep fault of the Lancang River and the division between the Lancangjiang ancient seam line, the Changning-Lancang post-uplift zone and the Baoshan back-arc basin are discussed. Secondly, the Gaoligongshan-Lu West metamorphic belt; Bomi-Tengchong mountain arc belt; Fourth, the Lanping-Simao Mesozoic depression basin, respectively, on the nature of the depression basement, Mesozoic depression, the evolution of graben basins and the formation of cutting trenches Problems were discussed; five, Ailao Mountain metamorphic belt of nature; six, Yidun - Zhongdian Island arc zone.