| This paper is based on the existing geological data and the predecessors’ study of the Huating coalfield and the Ankou-Xinyao coalfield, regarding the coal accumulation as the main direction, synthesizing methods of Coal Geology, Sedimentology, petrology and tectonics, combining with geophysical prospecting and indoor analysis, then summarizes the process of coal-bearing basin formation and distribution rules of coal seam.The research area is located in south-west of Ordos basin and east of Liupanshan,it has Huating coalfield and Ankou-Xinyao coalfield that two coalfields are inner-land coal-bearing basin. There are six coal measures bottom-up in the middle Jurassic coal-bearing stratum of Yan’an formation. The main minable No. 5 coal seam is thick, spreaded, and has large reserves, which is low ash, low sulfur, and high volatile.The Yan’an formation coal-bearing stratum is divided into three sections and four sedimentary cycles, No. 5 coal seam is at the middle-up of the first cycle of first section. Combining with occurrence static of coal seam, coal and rock characteristic, and sequence stratigraphy, this paper concluded that coal-bearing basin has alluvial facies deposit, fluvial facies deposit, Lake Delta deposit, and lacustrine facies deposits. No. 5 coal seam is mainly deposited in the peat bog on the delta plain. At the same time, warm and wet climate condition, a large number of palaeobotany, ideal palaeogeography and palaeotetonics created the great thick No. 5 coal seam. The coal seam accumulation is summarized by analysis of coal controlling sectors and it offered basis for mining and searching coal seam. |
