The middle upper Jurassic Jienu Group,distributed widely along Gerze Baingoin area of northern Xizang, is terrigenous deposit of remnant retroarc basin with a complete transgressive regressive cycle.

• 西藏北部改则班戈地区出露的中上侏罗统接奴群是残余弧后盆地的滨浅海相陆缘碎屑沉积,具有完整的水进水退沉积旋回。