Mesozoic sequence stratigraphy and its response to tectonic evolution of the eastern depression, North Yellow Sea Basin, North China

Abstract

The North Yellow Sea Basin is a Meso-Cenozoic continental sedimentary basin located between the Tan-Lu fault and the Imjingang orogenic belt. The Mesozoic strata of the eastern depression in the North Yellow Sea Basin consist of lower (lower part of the Upper Jurassic-Lower Cretaceous), middle (upper part of the Upper Jurassic-Lower Cretaceous) and upper (Lower Cretaceous) supersequences, comprising six third-order sequences, as inferred from seismic, core and well log data. There are five lithology-lithofacies architectures summarized in the third-order sequences of wells A, F, D, E, J, G and H, and they are the interbedded coarse and fine, asymmetric coarse–fine, fine-coarse–fine, coarse–fine-coarse and asymmetric fine-coarse. The basin-controlling faults and their assembly configurations during each tectonic stage were inherited and differential in the depression. The basin-controlling faults were dominated by extension, and strike-slip movement increased gradually during the early stage of the Late Jurassic-Early Cretaceous. The strike-slip faults were dominant at the late stage of the Late Jurassic-Early Cretaceous. Right-lateral trans-extensional faulting created the uplift-depression structural framework of the eastern depression. There was another trans-extension in the depression during the Early Cretaceous. Wells A, F and D record subsidence at three different structural locations in a trans-extensional tectonic setting. From the Late Jurassic to the Early Cretaceous, the fault movement changed from transtension to transpression, and the eastern uplift extended from the basin edge into the depression center (now the center turned into a structural high). The present-day central structural belt is a potential area for hydrocarbon accumulation, and its extended or down-dip area may become prospective areas for oil. Hydrocarbon traps analogous to the buried hill or igneous type oil reservoirs may be present in the up-dip area of the eastern uplift.