Characteristics and Evolutionary Pattern of Incised Valley in Chepaizi Area, Junggar Basin

It is important for sequence stratigraphy and oil-gas exploration to explore major internal sequence compositions such as the evolution of erosion and filling patterns. In this paper, incised valley characteristics and evolutionary model are studied using 3D seismic data, drilling data and paleontological data. The results show that there are a series of incised valleys in the study area, which are determined and divided into three different kinds of strike including E-W, S-E and N-S respectively by the seismic profile. The morphology of incised valleys on the seismic profile shows a V-shape, while the internal filling patterns are of progradational configuration, divergent configuration and on-lap configuration. Regional geological data indicate that Chepaizi area started to uplift during the Heisey-Indosinian movement, resulting in the formation of an incised valley by a drop in base level. After the Paleogene, the base level restarted to rise, so the incised valley started to fill, with the filling time related to the position of ancient coastline. The evolutionary model of incised valleys is controlled by tectonics, topography, paleoclimate and source supply.