1地质背景研究区处于特提斯-喜马拉雅造山带和扬子克拉通两大构造单元接合地带,属三江复合造山带。中甸甭哥碱性杂岩体位于三江地区蜂腰地带,属特提斯-喜马拉雅构造域东缘义敦岛弧带的南延部分。甭哥岩体呈岩株、岩枝集群式出露,最大的不足1 km2;主体近南北向展布于碧塔海-甭哥与纳帕海-土官村两组深大断裂,岩石以正 1 Geological Background The study area is located in the junction of the Tethys-Himalayas or Yangtze Craton, which belongs to the Sanjiang compound orogenic belt. The Zhongdian BeiGe alkaline complex is located in the pedestal zone of the Sanjiang region and belongs to the southern extension of the Yidun Island arc belt in the eastern margin of the Tethys-Himalaya tectonic domain. Jugei rock body is rock and rock branch is exposed in clusters, the largest is less than 1 km2; the main body is distributed in north and south direction in Bitahai-Jiaobei and Napahai-Tuguan Village,