Research Of The Characteristics Of Structural Deformation Of Early-middle Jurassic In Renacuo Area, Gaize, Tibet

Bangong-Nujiang suture zone is one of the most important Tibetan orogenic belt,which retains information on the evolution of the Tethys Ocean. Through the fieldmapping of regional geological survey at1:50000and tectonic analysis at1:10000atRenacuo,which is about50km from Gaize,as well as cleavage, lineation, huboccurrence statistics, derived that early-middle Jurassic formation had experiencedthree tectonic movements.The first stage controlled the main structure of the region, forming continuous largeanticlines and synclines in the area and the combination of folding style is Alpine.Itsmain stress is north-south. The principal stress of the second stage is nearly fromnorth to south, but the effect was significantly weaker transforming the structuralphenomenon of the first stage in small area and forming co-axial structuresuperimposed folds, S2cutting S1, folds of the foliation. The third tectonic movementis neotectonics featuring brittle deformation,mading the older thrust faults re-active,and form sinistral faults and right lateral strike-slip fault between Sewa formation andRiganpeicuo formation that caused the lost of the fisrt and second member of Sewaformation.By mapping two structural analysis geological map in northern Gaize Renacuo area,and combining with regional geological data and results of previous studies,theconclusion was drawn the main stress,which is nearly north-south, controlling thedeformation in Renacuo area is the result caused by the subduction of Meso-Tethysand the direction of the subduction is from south to north.