The Southern Segment Of Longmen Shan Fold-thrust Belts Structure Deformation Process Of Research

It is complicated that the southern segment of Longmen Mountains fold-thrust belts structure characteristics.Basis on the predecessors' research,balanced section,Structure,physical modeling experiment and the related study.The southern section of Longmen Mountains fold-thrust belt structural styles and structural deformation are analyzed in detail.Combined with previous studies,this paper discusses and analyzes the southern segment of Longmen Mountains thrust-slippage effect,structural evolution,etc.Directly analyzed the process since the indosinian period of the tectonic evolution.It has significance to know the formation of the southern segment of evolution.Through combination of field and indoor,the paper concluded the following understanding:(1)Southern segment of Longmen Mountains has three fault zone,Longdong,fracture,Yanjing-Wulong fracture,Dachuan-Shuangshi fracture has its own geological structure characteristics.Longdong fracture mainly characteristic is strike-slip with overthrust nappe,quartz lenses,joint,fold and fault development.Yan jing-Wulong fracture,fault block of both has the phenomenon such as extrusion,traction fold,cleavage,flow cleavage,foliation,mylonite,scratch,order step development,which is the strong compression.Dachuan-Shuangshi fracture interrupter by multiple fault,and formed by the nappe,which developmented many small and complex fold,brittle deformation,extrusion,sheet development,physical and chemical,lensing,syncline,exposed anticline.(2)The southern segment of Longmen Mountains fold-thrust belts can show a lot of thrust fault and associated fold,Tectonic imbricate type,strong brittleness and shallow.Longdong overall fracture is mainly about uniclinal structure,interior development secondary closed homoclinal fold.Yanjing-Wulong fault is the borderline for XiaoGuanZi fault zone,where north-western development thick skin structure,and the south-eastern development thin-skinned structure.The DachuanShuangshi main show is relatively open folds,which arch core often axxompanied by thrust fault.(3)Structural physical modeling can directly observation of structure deformation phenomenon,and combined with the PIV(particle image velocimetry)we can analyze the relationship between geometry and kinematics of structural deformation.By setting change single factor variables,to analyze which are mainly factors to the control of structure deformation and influence of structure deformation.Balanced section technique through the forward modeling and inversion,deepen the understanding of the geology in this area.Structural physical simulation and balanced section technique are worth promotion of technology in the field of geology,It has an important value about the geological study of a region.(4)Both strength and depth of the slip layer influence the structural evolution of fault fold,the smaller the strength of the slip layer,the farther deformation of the overlying strata propagation,the deeper the slip depth,also the farther deformation spread.Shallow slip layer control local fold fault structure,and deep basal slip layer controlling overall fold thrust belts style,and the fracture form in without slippage layer,single slip layer,and double slip layer are in turn order.Through the balanced section and sand box simulation calculation,Sourthern of Longmen mountains since indosinian period shorten at a rate of 32%.(5)Longmen Mountains fold thrust belts formed mainly experienced the following stages: Indosinian tectonic movement relatively small;At the end of the indosinian-yanshan period because of the land mass collide with each other,show the thrust nappe structure,under the steady effect from north to south,from north to south of nappe,the region formed a series of homoclinal,inverted or recumbent fold and thrust and nappe fault.Himalayan orogeny,entered the stage of intracontinental reconstruction in this area,on the structure performance for continuous thrust nappe,the dragon door mountain formed a large number of research structure,stratigraphic system to form a series of homoclinal or overturned fold and faul.