SEQUENCE STRATIGRAPHIC CHARACTERISTICS AND DEPOSITIONAL SYSTEMS IN THE SOUTHEAST OF THE EASTERN DEPRESSION OF THE NORTH YELLOW SEA BASIN

The sequence stratigraphy framework of the southeast of the Eastern Depression of the North Yellow Sea Basin was established by comprehensively study of drilling, well logging and seismic data in this paper. The Mesozoic of the study area can be subdivided into five third-order, two second-order and one first-order sequences. The spatial distribution of sedimentary facies and depositional systems indicates that four major depositional systems, say a fan delta, a braided river delta, a turbidite fan and a lacustrine system, occur in this region. During the early stage of faulting, there were a medium-sized fan delta and a braided river delta depositional system occurred in the west and east of JSQ1 respectively. During the middle stage of faulting, the fan delta system in the west expanded step by step and in the front of the system formed small turbidite fans. The braided river delta system in the east also prograded continuously and reached its maximum at the depositional period of JSQ4. During the late stage of faulting, only small basin-marginal fan bodies and nearshore-shallow lake facies developed in the sequence of KSQ1. The eastern and southern uplift received none or very thin sediments during the periods and dominated by erosion. The vertical evolution and spatial distribution of the depositional systems were controlled by paleotectonics and paleogeomorphology.