High-Resolution Seismic Stratigraphic Research Of Modern Marine Deposit In The Yellow River Estuary Area

Bohai Sea is a shallow inland basin submerged by the sea water, which is enclosed by Liaodong Bay, Bohai Bay, Laizhou Bay and Bohai strait, forming a cross-liked outline. The entrance of the yellow river is located in the southwest of Bohai Sea, at the end of long axis. Suffered from the action of river, sea, structure and weather, modern delta of yellow river is a complicated deposit system.High-resolution seismic profile is an important method and strong tool using in the modern seabed deposit investigation. Because of the complex surface structure and seism geological condition, the resolution and s/n of the seismic data gathered in the yellow river estuary area is very low. Aiming at these problems, this article discusses the gathering and processing methods of seismic data in paralic zone. As a result, high quantity seismic profile was obtained, which has important meaning to investigation methods of modern seabed deposit structure.Based on the theory of seismic stratigraphy and combined with the drill data and processed seismic profile, this article analyzes and interprets the seismic data. It can be divided into eleven seismic stratum units, including six marine facies layers and five continental facies layers from the time of middle Pleistocene. In addition, the seismic facies characters of every seismic stratum unit are described in this article.Researches show that besides plentiful seabed landslip, there are many other phenomenon appeared in yellow river estuary area, such as liquation collapse, erosion structures and asymmetric stratum. This article infers and analyzes these typical geology phenomenon reasonably and discusses their forming mechanism, characters in the profile, geological disaster that probably caused.The forming time and geologic period of every seismic stratum unit has been demarcated by way of the oxygen isotope curve and the nearby drilling data. It shows that those eleven seismic stratum units are formed since middle Pleistocene.The evolution of yellow river estuary area deposition environment is controlled by global sea level change and tectonic activities. Bohai has been continuously subsiding since the Quaternary Period, and the global sea level fluctuates frequently. So under this background, the estuary area shows a stratum sequence in which the marine facies layers and continental facies layers appear alternatively since middle Pleistocene.