There are significant differences between the foreland craton and the incretionary wedge of "orogenic zone" in crustal structure, mechanical property, et al. Compression makes the lateral variation of basin-mountain crust manifested by tectonic deformation. We set the sandbox modeling experiments of "craton" with two detachment layers directly contacting with "orogenic zone" with different competence, analyzing the impact of lateral variation between the crust of basin and mountain to the contractional structural deformation. The result indicates that, the relative rigid "craton" squeezes the relative weak "orogenic wedge", leading to the pop-up of "orogenic wedge". The "orogenic wedge" forms contractional deformation as well as abducting laterally(obliquely)to the "craton" and transmits contractional deformation to the interior of "craton" through the detachment layers of "craton". The detachment layers in different depth of "craton" result in the development of uncoordinated delaminate contractional structural deformation. With the lateral competency variation between the lithosphere "orogenic wedge" and "craton" increases, the amplitude of pop-up structure formed by the contraction of "orogenic wedge" decreases while the amplitude of recoil structure formed by "orogenic wedge" compressing "craton" obliquely increases, the adjustment capacity of the deep attachment layer of "craton" to the oblique thrust displacement of "orogenic wedge" weakened, while the adjustment capacity of the shallow attachment layer to which strengthened, the "orogenic wedge" transits from deep layer to shallow layer forming strong deformation belt, the contractional deformation of the edge to the interior of "craton" transits from the combination of thrust-fold in deep layer and fold-thrust in shallow layer to the combination of fold deformation in deep layer and fold-thrust in shallow layer, the structural deformation of foreland thrust belt in frontal zone transits from the "front distributed wedge imbricated fanshaped tectonic" in deep layer to the fold deformation in shallow layer. The experimental results could enlighten the interpretation of the complicated formation mechanism of the piedmont fault belt in northwest China.
. The impact of lateral variation between the crust of basin and mountain to the contractional structural deformation: Insights from sandbox experiments[J]. Chinese Journal of Geology, 2015, 50(2): 581-596.