Sedimentary characteristic and coal accumulation in coal measures in Hongshandian mining area, Hunan

Based on the study of predecessors’ research results,the sedimentary environments and their influence on the development and distribution of coal seams of Hongshandian mining area are systematically analyzed by field geological investigation,sample testing and comprehensive data analysis,the results can be used to predict advantageous areas of deep coal resources.By using sequence stratigraphy analysis,sedimentary facies division and lithofacies paleogeography recovery,two third sequences including sequence I and sequence II were divided,one transitional surface of middle-term base level cycle was distinguished.Sequence I was divided into one declined half base level and one risen half base level,the stratigraghic framework of Longtan and Dalong Formations was established,deltaic plain facies,deltaic front facies and prodelta facies were distinguished,the lithofacies paleogeographic map was recovered.The sediment sources came from NNE direction,seawater invaded from the south to the north,swamp environments between distributary channels were the most favorable environments for coal seam development,the predicted favorable area for deep coal resource exploitation is located between Shexingshan district and Nantang syncline.