Physical modeling of Cenozoic fold-thrust belts formation mechanism in northwestern Qaidam Basin

By tectonic physical modeling,geologic models were developed based on the geological conditions of the northwestern part of Qaidam Basin. And the formation mechanisms of fold-thrust belts were studied in this region. The results show that the formation of fold-thrust belts in the region is controlled by rigid arc-shaped boundary of Saishenteng mountain and detachment layer of Jurassic mudstone with huge thickness. Fold-and-thrust belts were gradually propagated from the northwest to the southeast,with the shapes changing from curved to straight. The shortening strains accumulated mainly on the thrusts on the both sides of anticlines and their extremum concentrated in the newly generated active part of the fold-thrust belts. The shear strain distributed at the fold-thrust belt intersected with extrusion direction.