Characteristics of jurassic sequence stratigraphy in the middle area of junggar basin

With the application of the theory of high-resolution sequence stratigraphy referred to the base-level, and drilling data and seismic and logging data, we identify the sequence interfaces within the Jurassic in the middle area of Junggar basin. Seven sequence boundaries are identified corresponding to one long-term base-level cycle and six mid-term base-level cycles. The boundary of long-term base-level cycle is a regional unconformity surface, however, the boundaries of mid-term base-level cycles are local unconformities, sedimentary transformation surfaces or sedimentary erosional surfaces. The identification of the sedimentary transformation surfaces is important to the identification of the boundaries of mid-term base-level cycles.