Sequence strata and the coal accumulation of Wunite coafield, Inner Mongolia

Based on the study of the stratigraphy sequence of the Bayanhua Formation of low Cretaceous in Wunite coafield, two sequence boundaries SB1 and SB2 were distinguished, three third sequences including SMC1, SMC2 and SMC3 were divided, and the stratigraphy framework of the Bayanhua Formation was established.The facies analysis shows that the strata were developed from lacustrine facies, delta facies and fluvial facies deposition.And lake offshore facies and river delta facies were the predominant paleoenvironment for coal formation.Finally, according to the core data, thickness of the coal layer, the proportion of sand and mud in the strata and the distribution of the stratigraphy sequence, the lithofacies paleographic map was made, which will provide a helpful guidance to the exploration and development of the coal around the area.