Geological interpretation of seismic sections and tectonic evolution of the North China basin

Abstract：The seismic sections show that the development of the North China basin is represented by accordion-style evolution. Generally three-layer“faulted-downwarped” structure formed：(1) Meso- and Neoproterozoic “faulting” and Paleozoic-Triassic “downwarping”, (2) Jurassic “faulting” and Upper Cretaceous “downwarping”, and (3) Paleogene "faulting" and Neogene “downwarping”. Faulting and downwarping resulted from extensional and compressional stress fields respectively. The change in the stress field was caused by the change of the dip angles of subduction of the adjacent oceanic plate from low to high. Due to the polycyclic crustal movements, structural and sedimentary evolution took place several times, forming several source-reservoir-cap associations and several trap types of oil/gas accumulations. Geological conditions of oil/gas accumulations may have formed in various downfaulted-downwarped basins from the Meso- and Neoproterozoic → Paleozoic → Mesozoic → Cenozoic,