Abstract:

In the research of tectonic evolution with the balanced section technique, there is some difficulty in achieving the balance of the section because of the irregularly plastic deformation of the layer. To solve this problem, the layered technique is proposed to eliminate the influence of plastic layer, that is to recovery the formations which are on and under salt rocks respectively, then the salt is controlled by both of them to dominate the deformation amplitude, and finally the balanced state is achieved. The proposed method can effectively eliminate the effect of plastic layers in the study of tectonic evolution of Late PaleozoicMesozoic strata in northeastern Sichuan. According to the study, the formation of the ancient tectonic frame of northeastern Sichuan has experienced the early extension, the midterm transition and the later extrusion process, and manifests the structural characteristics of the early normal fault, the midterm reversal structure, and the later thrust nappe structure; the gypsumsalt rock which is 500meter thick in JialingjiangLeikoupo Formation has played an important role in the deformation process.

Key words: layered technique, balanced cross section, structural evolution;northeastern Sichuan