Abstract:

Meso-Cenozoic terrestrial petroliferous basins in East China are rift-valley basins developed in stretch tectonic system. They occur as graben-horst or half graben-half horst configuration and have no distinct compressive deformation.The fundamental factor is deformation of sedimentary rocks caused by gravity effect. The structural deformation resulted from lowering gravity potential is known as gravity structure. Based on seismic data, the authors divide the gravity structures in rift-valley basins into seven types by their origin:sliding fault steps,rollover anti-clines, tilted blocks, slide-dropped anticlines, nappe-gliding structures, com-pactional structures and diapiric structures. The motive force that caused the structures is the uneven density and un-stable gravity potential. Such motive force makes the gravity structures to dis-tribute in order in the basins and provides fine traps for the formation of oil and gas pools.