The Helan-Chuandian N-S Tectonic Belt is a mantle transitional belt in China.The southern part,forming the Chuandian N-S Tectonic Belt,comprises several tectonic systems,each displaying different characteristics.The Chuandian N-S Tectonic Belt along the western margin of Yangtze Block is a strike-slip tectonic belt with a series of echelon left-lateral slip faults.The strike-slip fault systems experienced two stages of structural deformation:early NW-SE striking thrust faults formed under a NE-SW compression stress field,and later sinistral strike-slip structures formed along thrust faults under a NW-SE compression stress field.Mesozoic basins developed between the left-lateral slip faults.Sedimentary facies and paleocurrent directions indicate that basin development was controlled by the strike-slip faults.The oldest strata in the Chuandian N-S Tectonic Belt constrain its formation to early Mesozoic.In fact,The slip tectonic belt formed by clockwise rotation and north-directed subduction-collision of the Yangtze Block in Late Triassic-Jurassic.The strike-slip faults that developed within the belt also formed at this time.
