Sedimentary Facies and Coal-Accumulation of the Early-Middle Jurassic in Toksun Coalfield Northwestern China

This paper mainly discusses the sedimentary facies and coal accumulation of the Badaowan Formation and Xishanyao Formation in Toksun coalfield, Turpan- Hami Basin. Based on drill and well logging data, fan-delta facies, delta facies, lacustrine facies, swamp facies and flood plain facies were identified. Sangonghe Group and Xishanyao Group were the coal accumulating periods during the Early-Middle Jurassic, including three subgroups: Badaowan, Early Xishanyao and Late Xishanyao groups. The coal-accumulating patterns were different because of the different coal accumulating environments. The stable, simple structure and thick coal seams were formed in the meandering stream plain of the Late Xishanyao Formation.