滇西北大地构造单元的划分与特征

摘要

Tectonically,the northwestern Yunnan area may be separated into 3 first-order tectonic units,10 second-order tectonic units and 25 third-order tectonic units. From west to east,the above-mentioned 10 second-order tectonic units consist dominantly of the Dulongjiang arc-basin system,Bingzhongluo block,Mode suture zone,Chongshan block,Lancangjiang volcanic arc,Lanping block,Yunling continental-margin arc,Jinshajiang suture zone,Xianggelila block and Garze-Litang arc-basin system. The boundary faults are assembled,from west to east,by the Gaoligongshan fault, Bangdang fault, Fugong fault, Biluoxueshan fault, Jicha fault, Deqen-Xuelongshan fault, Yangla-Dongzhulin fault, Jinshajiang fault, Xianggelila fault and Sanjiangkou fault. The classification scheme proposed in this paper represents the new progress and refinement of the tectonic units in northwestern Yunnan.%从鉴别陆块（地块）、结合带边界断裂入手，将滇西北大地构造划分为10个二级单元。根据地质体属性及重要断裂，在二级单元内划分出25个三级大地构造单元。结合西藏、滇西南部地区资料，归并为3个一级大地构造单元。二级大地构造单元自西向东为：独龙江弧盆系、丙中洛地块、莫得结合带、崇山地块、澜沧江火山弧、兰坪地块、云岭陆缘弧、金沙江结合带、香格里拉地块、甘孜-理塘弧盆系。分界断裂自西向东为：高黎贡山断裂、棒当断裂、福贡断裂、碧罗雪山断裂、吉岔断裂、德钦-雪龙山断裂、羊拉-东竹林断裂、金沙江断裂、香格里拉断裂、三江口断裂。该划分方案较为全面地反映了滇西北区域地质调查和科学研究的新进展，对前人划分方案进行了有依据的修改调整，二级、三级大地构造单元的划分尺度统一，厘定了各级大地构造单元的边界断裂。