经研究，解体了沿用近６０年的敦煌群。敦煌群是经受多期次构造变形—变质作用改造和重建的复杂地质体组合，可以分解成灰色长英质片麻岩、变质表壳岩和中浅变质侵入岩。依岩石学、岩石化学、副矿物等特征研究，灰色长英质片麻岩原岩是经中、深变质的侵入岩。变质表壳岩是构造无序岩层。依据构造—岩石地层法准则重新厘定了敦煌岩群，并新建大坝岩组。敦煌岩群划归晚太古代—早元古代；而大坝岩组划归中元古代。 After the study, the disintegration of nearly 60 years of Dunhuang group. The Dunhuang Group is a complex geological body assemblage that has undergone multi-stage tectonic deformation-metamorphism remodeling and reconstruction. It can be decomposed into gray feldspathic gneiss, metamorphic crust and medium-shallow metamorphic intrusive rocks. According to the petrology, petrochemistry and accessory minerals, the gray-feldspathic gneiss protolith is a medium- and deep-metamorphic intrusive rock. Metamorphic case rock is the structure of disorderly rock formation. Based on the tectono-lithostratigraphic criteria, the Dunhuang rock mass was re-determined and a new dam group was formed. Dunhuang rock group is assigned to Late Archean - Early Proterozoic; while Dam Rock Group is assigned to the Mesoproterozoic.