东胜煤田延安组岩相古地理

Based on the analysis and study of the petrology features of the revealed stratum of No. 1 well tunnel in Selian coalmine which is under construction, northwest of Dongsheng area, and a large number of borehole datas in exploration stage, the auther has expounded the relationship between petrology features of coal bearing stratum and evolution of sedimentary environment in the Middle- Lower Jurassic Yan'an Formation. The results shows that the Yan'an Formation(J1-2y) is a set of dark gray sandstone, siltstone, silty mudstone, mudstone and coal. There are gradations from the fluvial sedimentary system to the lake delta sedimentary system from the base upwards in the Yan'an Formation , and finally into the fluvial sedimentary system.