Depositional environments of the coal-bearing strata and their controls on coal seams in the Yangquan mining district,Shanxi

The exposed strata in the Yangquan mining district,Yangquan,Shanxi consist,from east to west,of the Ordovician,Carboniferous and Permian strata.
The coal-bearing strata here are mosdy composed of Upper Carboniferous Taiyuan Formation and Lower Permian Shanxi Formation,and laid down in the terrestrial-marine transitional environments. The Taiyuan Formation represents a succession of mixed littoral,carbonate platform and deltaic sediments,while the Shanxi Formation represents a succession of delta plain sediments.The occurrence and thickness of the coal seams are controlled by depositional environments.For instance,the coal seams developed on littoral bars tend to be relatively thick,with thick coal seams overlying upon the underlying sandbodies;those grounded on delta fronts tend to be less thick and arranged locally upon the channel mouth bars,and those in the transitional zones between upper and lower delta plains also tend to be relatively thick,with thick coal seams unconformably overlying upon the underlying sandstone bodies.The results of study have assisted in the further exploration and exploitation of coal resources in the study area.