滇西时代不明变质岩系的解体和时代厘定

Analysis of the undating metamorphics in West Yunnan and determination of its age

摘要: 建立在岩石组合、变质、变形、碎屑组分和同位素年代学基础上的研究成果表明,滇西时代不明变质岩系是两个时代不同的构造岩片,分别相当于中元古界崇山群和二叠系吉东龙组,二者是喜山期构造混杂带的重要组成部分。崇山群在晚元古时期（727～956Ma）发生区域性的动热变质作用,加里东时期（397Ma）又叠加了一次变质作用。吉东龙组中有喜山期（32Ma）变质作用的叠加。

Abstract: On the basis of the study on its association, metamorphism, deformation, composition of debris and isotope geochronology, it indicates that West Yunnan undating metamorphics belongs to tectonic rock sheets of quite different two periods,the Middle Proterozoic Chongshan Group and the Permian Jidonglong Formation ,respectively,both of which are the dominant components of the Himalayan mixtite belt.One regional dynamothermal metamorphism took place in Chongshan Group during Upper Proterozoic Subera （727-956Ma） , and another metamorphism superimposed it during Caleodonia period （397Ma）, compared with superimposed metamorphisms in Jidonglong Formation during Himalayan period （32Ma）.