潮下砂坪上泥炭沼泽的形成条件及发育特征山西岩溶陷落柱的岩体力学背景

用沉积地质学的研究方法对内蒙古乌达矿区晚古生代太原组１５号煤层下含煤岩系的岩石学特征、沉积层序和展布格局进行了详细研究，认为１５号煤层堆积于潮下砂坪沉积环境．对煤层本身的分布和煤岩学、煤质特征研究结果表明，该煤层的厚度分布稳定，与正常海相形成的煤相比该煤层中硫分偏低，惰性组分和矿物含量高，活性组分较低，并含有火山灰夹矸．因此可以推测，１５号煤层是在一种剧烈的地壳抬升作用下，由于海水迅速退出本区使潮下砂坪沼泽化而形成的．

Formation and characteristics of the mire on the subtidal sand flat environment

By means of the research method of sedimentary geology, it is studied in detail on the petrologic characteristics, sedimentary sequences and distribution of the coal bearing strata below seam No 15, Taiyuan Formation in the Wuda Mine District, Neimenggu Autonomous Region, China.It is recognized that the seam No 15 was accumulated on the subtidal sand flat environment.The seam distribution is very stable and its thickness is around 2 meters.The characteristics of coal petrology and coal quality in the seam No 15 show that the inertinite and minerals are high, the reactive maceral and the sulfur content are relatively low.The tonstein formed by volcanism is found in the seam No 15.Therefore, it could be concluded that the seam No 15 was formed in the mire of the subtidal sand flat during the crust movement in the research area were acute rising, when the sea withdraw from the area.