Evaluation Of The Structural Evolution Of Southern Dabashan Thrust Belt Using2D Seismic Cross Sections

East Asia is a region of complex crustal evolution and is composed of PreCambrian cratonsand three major Phanerozoic tectonic domains: the PaleoAsian Ocean Tectonic Domain, theWestern Pacific Tectonic Domain and the Tethys Tectonic Domain. The interaction betweenthe three domains resulted in complicated topographic features, deep-geophysical signatures,and geochemical records. No place on Earth displays more diverse and complex patterns ofactive and ancient deformation as recorded in the geologic and tectonic evolution of Asia.Multi-level thrusting and detachment are important kinematic mechanisms of the forelandthrust belts in central-west China. Seismic explorations have revealed that passive-roofduplexes are widely distributed in basin-mountain transitional zones in West China This typeof structure has attracted increasing attention in that provide information on orogenic beltsThe Dabashan is generally considered as a foreland thrust belt formed as a result of thecollision of the North and South China plates, Situated as a special tectonic portion in thetransition zone from the Sichuan basin to the Qinling orogenic belt, the Dabashan forelandthrust belt provides a key area wherein to investigate the relationship of compression basin-mountain coupling.Using a2D seismic cross sections and detailed surface geological cross section, wedetected two detachment faults at the base of the Sinian strata and the lower Triassicstrata,with imbricated thrust faults fro, Sinian to Lower Triassic, we also detect an upliftingprocess happened to the SW of the belt, which lead us to conclude that Southern Dabashanis a typical duplex structure. By establishing a restoration models, we calculated that theamount of shortening was approximately27%for line Zhen04-01and25%for line Zhen04-02and for42%for line Zhen04-03to the SW, where we thought that the SouthernDabashan thrust belt was affected by the movement that happened in the Xuefengshanforeland area. These clues, supporting the theory that Southern Dabashan had been formed intwo stage Mesozoic tectonic evolution.