Sequence-paleogeography and coal accumulation of coal-accumulating period in the western part of Muri coalfield

In order to reveal the coal series sedimentary environment and coal accumulation regularity of Muri coalfield, based on the existing research and the analysis of field reconnaissance and drilling data, this study mainly focuses on the sequence-paleogeography and the coal accumulation analysis of the Early-Middle Jurassic sedimentary strata in the major coal accumulating period of the western part of Muri coalfield. The results showed that Mid-Lower Jurassic strata can be divided into four third order sequences. The early-mid Middle Jurassic(the deposition period of sequence 2-3) was the major coal accumulating period in the western part of Muri coalfield, when the strata was deposited in braided river delta plain, delta front and shallow lake, and provenance direction mainly comes from NE. The coal accumulating environment in the early Middle Jurassic is the best of coal-accumulating period, forming the coal accumulating center in Juhugeng. But in the mid Middle Jurassic, the coal accumulating environment was relatively poor, so the coal seams become thin and numerous, and the coal accumulating center moved westward to Xuehuoli and Duosuogongma. All the results showed that the sedimentary facies and paleogeography characteristics have remarkable influence and control on coal-accumulating process. The above understanding provided important guidance to coal exploration and development in the western part of Muri coalfield.