TECTONIC ANALYSIS OF SUPERIMPOSED BASINS

Major petroliferous basins in China are characterized by poly-stage superimposition.The evolution of basins is stepwise.Different evolutionary stages have different geotectonic environment,continental oceanic distribution and proto tpye basins.The important features of superimposed basins in China are interfracture emplacement and intermountain emplacement.This reflects that the basins have experinced poly-stage extension cracking,subduction,collision closure and the extension compressional cycles in post-collisional periods.In the tectonic analysis of superimposed basins,more attention must be paid to the study of the Paleozoic untypical craton,the Meso-Cenozoic untypical foreland basin and their superimposition history.So, the key tectonic periods of cransformation and their effects on the transition of basin types are determined,the deformed styles in the different tectonic periods of basins and their changing in plane and in section are analysed,the basement-cover united tectonic deformation history is revealed,and the forming course and coupling history of basin systems are restored.This privides background information for the hydrocarbon generation,migration and accumulation in superimposed basins.