Study On Influences Of Lateral Friction And Erosion On The Formation And Evolution Of Fold-and-thrust Belts By Physical Modelling

Various factors influencing the structural evolution of fold-and-thrust belts have been widely researched,but the effects of lateral friction and erosion have rarely been given sufficient attention.Some previous studies indicate that lateral friction directions and erosion have noticeable effects on the structural deformation of fold-and-thrust belts.However,due largely to the lack of systematic researches,the effects of lateral friction and erosion on the structural evolution of fold-and-thrust belts are still far from being fully understood.In order to look closer at the effects of lateral friction and erosion on the structural evolution of fold-and-thrust belts,we conduct a series of sandbox models under different basal conditions and mainly reach the following achievements:(1)in the presence of weak basal décollements,the direction of lateral friction can control the structural vergence of fold-and-thrust belts,and the structural vergence is always same as the direction of lateral friction;(2)back-wall push and base pull models have obviously different structural deformation in the same lateral friction direction;(3)erosion in the uplift region of convergent boundary promotes the reactivation of structural deformation,which cause more shortening accommodation of the boundary thrust and the eroded region to rise to previous height and (4)the effects of erosion on fold-and-thrust belts strengthen with increasing erosion rate in the same condition?strengthen with increasing velocity and weaken with thickening brittle layers under the same erosion rate.