滇东黔西上二叠统含煤岩系形成于陆相到海陆过渡相环境中,其泥岩的粘土矿物组成可以反映这种环境背景。该区泥岩粘土矿物类型以高岭石和伊利石/蒙皂石间层矿物为主,伊利石次之,局部层段见较少绿泥石及蒙皂石。垂向上,高岭石在富源后所矿区、盘县盘关矿区剖面中下部(即宣威组中、下段和龙潭组)含量偏高;伊利石在织金矿区剖面上部(长兴组)和下部(龙潭组下段)含量明显偏高,而在剖面中部(龙潭组上段)偏低;伊利石/蒙皂石间层矿物在后所矿区、盘关矿区、纳雍矿区占绝对优势,而在织金矿区仅在剖面中部含量较高,并与伊利石呈明显的负相关关系;蒙皂石含量很少,仅出现于盘关矿区和织金矿区剖面的上部和下部。粘土矿物的上述分布特征可大致反映出龙潭早期为海侵期,龙潭晚期为海退期,长兴期为新的更大的海侵期。平面上,从陆到海,即从滇东的冲积平原河流体系,向东经盘关向斜的上三角洲平原、纳雍的过渡带三角洲平原,到织金的下三角洲平原及潮汐平原,高岭石含量急剧减少,伊利石含量逐渐增加。最为明显的是从滇东河流体系到黔西三角洲—潮坪体系之间高岭石含量骤然减少。
The Upper Permian coal-bearing series in eastern Yunnan and western Guizhou, China, were formed in a continental to a marine-nonmarine transitional setting, which are also reflected in the clay minerals of the mudstones. The clay minerals in these mudstones are predominantly kaolinite and illite/ smectite mixed-layer followed by illite and minor amount of chlorite and smectite. Kaolinite concentrates in the middle-lower part of the sections (the middle and lower members of Xuanwei Formation and the whole Longtan Formation) both in the Housuo Coal Mine of Fuyuan, eastern Yunnan, and the Panguan Coal Mine of Panxian, western Guizhou. Illite has a higher proportion both in the upper part (Changxing Formation) and the lower part (lower member of Longtan Formation), and a lower proportion in the middle part (up- per member of Longtan Formation) of the sections in Zhijin Coal Mine areas of western Guizhou. Illite/ smectite is the dominant clay mineral in the mudstones of the three sections in Housuo, Panguan and Nayong Coal Mine areas, and has a high proportion in the middle part of the section, showing a negative correlation with the illite in the Zhijin Coal Mine area. Smectite is of little abundance, and presents only in the upper and lower parts of the two sections at the Panguan and Zhijin Coal Mine areas. These stratigraphic distributions of the clay minerals are believed to be the response of the palaeogeographic evolution, that is, the transgression during the Early Longtan stage and regression during the Late Longtan stage, and a new more extensive transgression during the Changxing stage. From west to east, i.e. from the alluvial fluvial system in eastern Yunnan, across the upper delta plain in Panguan Coal Mine and the upper and lower delta plain transitional zone in Nayong Coal Mine, to the lower delta plain and tidal plain in Zhijin Coal Mine, the kaolinite abundance significantly decreases, while illite abundance gradually increases.