Abstract
The formation of coal accumulation units requires specific geological conditions, including fossil plants, palaeostructure, palaeoclimate and palaeogeography. The Ordos Basin has experienced multiple sedimentary environments during its evolution. The different depositional systems and system tracts represents the important sedimentary events during the basin's evolution. Therefore the different coal accumulation conditions results in various characteristics across the coalfield. Coal was the most important energy source from late Palaeozoic and Mesozoic sediments in the Ordos basin. It generates abundant coalbed methane. The coal accumulation zones developed generally in the basin slope environment, where many sand bodies were located. Abundant petroleum, natural gas and uranium exist in these sand bodies. Our study indicates that the oil, gas and uranium are related to the location of the coal accumulation in the Ordos basin. The transgressive coal and the allochthonous tempestite coal were developed in the Late Palaeozoic and Mesozoic.