THE EVOLUTION AND BASIC STRUCTURAL FRAMEWORK OF THE BASEMENT OF THE YUNKAI UPLIFT

The basement of the Yunkai uplift is characterized by a two-ldyer structure.The deeplevel basement consists of the Early-Mid Proterozoic medium-to high-grade metamorphic series and migmatites and granites resulting from their anataxis. Among other things, Kfeldspar spherophyric granites have the magmatogenic features with crystallization ages ranging from 390 to 510 Ma. After its formation the basement of the uplift experienced a long anccomplex evolutionary history of metamorphism and deformation since the Jinningian Staguntil the metamorphic core complex or domal structure was formed in the Caledonian Stage,thus laying a foundation for the basic structural framework of the Yunkai uplift.