Sedimentary environment and coal accumulation patterns of the Liushu basin, Heilongjiang Province

Liushu basin is a caol basin which is closely related to the tectonic activity of Dunmi fracture belts, mainly develops the CretaceousMuling group. Using Liushu basin's measured sections, drilling cores and well logs data to study the depositional environments and sequence stratum and coal bearing characteristics of Cretaceous coal-bearing stratums. In the research area we identify 5 kinds of lithofacies and 11 types of lithofacies, identify5kinds sedimentary system and 11 kinds sedimentary facies. In the east of Heilongjaing we identify 6 sequence boundaries, 5three-grade sequence interfaces. Liushu basin mainly develops sequence S4 and S5. The deltaic plain swamp which developed at transgression system track is the mainly coal forming environment.