Study On Sinian-Permian Sequence Stratigraphy And Sedimentary Facies Of Yalu River Basin

The Yalu River basin locates in the area of Tonghua and Baishan, southern Jilin Province, adjacent to North Korea in the south. It may be a good potential hydrocarbon source rock which developed numerous deep shale and coal from Neoproterozoic to Mesozoic. Besides, it is rich in reef flats , oolitic beach, storm deposit and large-scale deltaic sand body. The huge overlapping of Laoling regards as the capping bed cover on the basin underlying, which includes enormous regional folds and faults. Therefore, the research of oil and gas in Yalu River basin has an outstanding meaning for the petroleum potential estimation.According to the structural sequences, uplift and depression of the platform, there are three megasequences from Sinian to Permian—MS1 in neoproterozoic, MS2 in Eopaleozoic and MS3 in Neopaleozoic. Then, based on the evolutionary phases in every period of the Yalu River basin, we divide three megasequences into nine supersequences. They can also be separated into 26 third-order sequences on the basis of relative strata, which are bounded by surfaces of the erosion or nondeposition, or their correlative conformities within the nine supersequences above.The Yalu River basin has undergone three different depositional systems: 1.The detrital of terrigenous origin depositional system from Diaoyutai to Qiaotou Formation in neoproterozoic. 2. The carbonate platform sedimentary facies of depositional system from Wanlong to Majiagou Formation. Particularly, they were restricted platform facies in lower-middle Cambrian, then transferred into open platform facies in ZhangXia formation, slope and continental shelf facies in Late Cambrian and lower Ordovician, restricted platform facies in Yeli and Liangjiashan Formation. 3. Benxi to Shihezi Formation from Carbonic to Permian period belonged to delta facies and meandering facies depositional system. After Taiyuan formation, the region transits into continental deposition.