贵州晚二叠世各煤田含煤性分析

贵州地处扬子地台的西南缘，晚古生代受南北向挤压产生黔中隆起，同时在隆起南侧形成EW向纳雍—瓮安断裂，以此断裂为界，北部隆起，南部坳陷。在黔北台隆区内分布有毕节煤田、黔北煤田、黔东北煤田；黔南坳陷区分布有六盘水煤田、黔南煤田、黔东南煤田、织纳煤田、贵阳煤田。受构造控制，黔北台隆区晚二叠世含煤地层沉积厚度普遍小于黔南坳陷区，含煤性也较黔南坳陷差。根据含煤地层沉积环境差异，自西向东分为宣威相区（陆相）、龙潭相区（过渡相）和吴家坪相区（湾相）。黔北、六盘水、织纳煤田为海陆交互相沉积环境，三角洲发育，特别是织纳煤田受一组共轭剪切断裂及黔中断裂影响，整体呈三角坳陷，有利于碎屑物堆积，在其广阔的三角洲间湾发育了较好的泥炭沼泽，聚煤条件好，形成50余层煤，平均总厚度38.76m。陆相区的毕节煤田以河流相沉积为主，含煤10余层，煤层厚度变化大。黔东北、黔南、黔东南煤田以海相沉积为主，黔东北、黔东南煤田仅在底部含煤，层数少，仅一层可采。古构造、沉积环境是影响各煤田含煤性差异的主要因素。

Coal-bearing Property Analysis of Late Permian Coalfields in Guizhou Province

The Guizhou Province is situated at southwestern margin of the Yangtze platform, Qianzhong uplift had formed during Late Paleozoic as a result of NS trend compression, meanwhile an EW trend Nayong-Wengan fault was formed at south side of the uplift, as a boundary, to the north of the fault is an uplift, while to the south a depression. In the Qianbei anteclise have Bijie, Qianbei and Qiandongbei coalfields; in Qiannan depression have Lupanshui, Qiannan, Qiandongnan, Zhina and Guiyang coalfields. Controlled by tectonics, Late Permian coal-bearing strata depositional thickness in Qianbei anteclise area is commonly less than in Qiannan depression area and coal-bearing property also poorer. Based on coal-bearing strata depositional environment differences, from west to east can be divided into Xuanwei facies area （limnic）, Longtan facies area （intermediate） and Wujiaping facies area （estuarine）. The Qianbei, Lupanshui and Zhina coalfields were under continental-marine delta developed interactive environments, especially the Zhina coalfield was impacted by a set of conjugate shear fractures and Qianzhong fault and shown itself a triangular depression as a whole, in favor of clastic material accumulation, in the broad deltaic interdistributary bay developed rather good peat bogs, thus a good coal-accumulating environment, the coalfield contains 10 more coal seams, but the coal seam thickness variable. The Qiandongbei, Qiannan and Qiandongnan coalfields were deposited mainly marine sediments, in Qiandongbei and Qiandongnan coalfields have very few coal seams in bottom part, and only one is mineable. Paleostructure and depositional environment are major influencing factors of coal-bearing property differences between coalfields.