Structural deformation in the Yunzhug Formation in the Nadang region,Xizang

The epimetamorphic sandstone and slate associations,two-component interbeds,faults and folds are well developed in the Carboniferous Yunzhug Formation in the Nadang region,Xizang.The Yunzhug Formation may be divided,in the light of textures and structures of the rocks,into the upper,middle and lower members,and spanned three phases of tectonic evolution during the Middle-Late Permian to the Late Triassic.The regional geological data have revealed that the Yunzhug Formation was once laid down in the extensional passive continental margin bathyal environment.