关键词: 东濮凹陷, 浅水成盐, 低位盐, 砂体分布, 高频振荡湖盆, 古地理环境

Abstract: The observation result of cores and stratigraphic correlation showed that the salt rocks in the third member of the Shahcjic Formation of Dongpu Depression were associated with deep gray mudstone, gypsum mudstone and sandstone,and the salt rocks were deposited during low-level period. In the high-level stage,delta and fan delta were developed on the basin margins,and deep gray mudstone and a few gravity flow sandbodies were developed in the center of basin. In the low-level stage,the area of lake was exposed on the surface, because of the shrinking of lake. As a result,the sediments were salt rocks, gypsum,gypsum mudstone,carbonate rocks, calcilutite and drag flow sandstone from the center to the margin of the basin. The frequent change of water depth resulted in the Erequent alternation of dark mudstones and low-level salt rock and sandstone. The paleogeographic environment of the high-frequency oscillating lake basin and the relationship between distributions of sandstone and salt rock as well as between the distribution of salt rock and the deposition center were studied. A new conclusion different from the theories,such as "deep water salts-forming","high mountain and deep basin" and "hackberry facies sand",was obtained. The new conclusion will he useful for confirming the resource potential and indicating the exploration target of Dongpu Depression.

Key words: Dongpu Depression, shallow water salt-forming, low-level salt, sand distribution, high-frequency oscillating lake basin, paleogeographic environment