Abstract:

Beach bar is a new exploration field for the rifted basins in the Shubei area of the western sag, Liaohe Basin. In this paper,
the main controlling factors for the development of the beach bars in the study area were addressed. Results show the factors include
the palaeogeomorphology, palaeodepth of water body, palaeosource and palaeowind. These can be summarized as a control system of
tri-end members of “wind-source-basin”. The method to quantificationally reconstruct the four factors are proposed. The beach bar in
the study area is mainly developed in underwater uplifts. The favorable palaeodepth of water body is approximately 7 m. The
palaeosource comes from the transformation of delta, erosion of buried hill and reformation of coastline bedrock. The formation of the
beach bar is influenced by the north-south monsoon, the wind force reaching 8th grade. According to the controlling factors, the study 
area can be divided into five zones, including coastal zone, buried-hill drapping zone, buried-hill draping zone, northern slope zone and
deep depression zone, of which the buried-hill draping zone is most favorable for the development of beach bar.

Key words: Shubei area, the Upper Fourth Member of the Shahejie Formation, beach bar, controlling factors