Coal Forming Environment of Zhiluo Formation in Erdaoling Mine of Lanshan Coal Field, Inner Mongolia

The Erdaoling mine is located on the western margin of the Mesozoic Odors basin and belongs to continental elastic deposit during the Jurassic period. From the bottom up,the strata are the Fuxian,the Yan'an,the Zhiluo and the Anding Formations. In the past,it was thought that only the Yan'an Formation contains coal in the Jurassic systerm of the basin. However,recent explorations have shown that the Zhiluo Formation also has some minable coal seams in a certain area. After study of rock outcrops,well logs,borehole cores,the sedimentary facies of the Zhiluo Formation has been divided and the rule for coal accumulation was explored,and moreover,the coal-bearing strata were predicted. The author suggests that the Zhiluo Formation belongs to the typical fluvial sedimentary facies,which cab be further refined to the channel,flood-plain and backswamp microfacies. Coal seams are mainly formed in the backswamp microfacies and the spatial distribution of the coal seams is under control of the sand bodies of the channel microfacies.