COAL-ACCUMULATING ENVIRONMENTS OF EARLY QIXIAIAN AGE （EARLY PERMIAN） IN GUIZHOU AND THE DIRECTION IN COAL FINDING

The early Qixiaian stage of the early Permian is one of the coal-accumulating stages in Guizhou. Coal measures and coal seams are widespread and there is a relatively complete range of coal ranks. Some intermediate and small-sized coal deposits have been exploited and utilized. In this paper a relatively comprehensive study has been made on the laws of distribution and changes of the coal measures, seams and quality and their relations to lithofacies and paleogeography and a future direction in coal finding has been pointed to. According to the characteristics of the coal measures, the whole province may be divided into coal-bearing areas （including eastern, western and northern Guizhou） and barren areas （which refer to areas from Kaiyang and Dafang in central Guizhou to southern Guizhou and northwestern Tongzi）; the coal-bearing areas may be further divided into the eastern single coal seam area and the western multiple coal seam area with the Bijie-Panxian line as the boundary. Minable coal seams are mainly distributed on both flanks of the Hunan-Guizhou-Guangxi land and the margin of western Guizhou. A great mass of data indicate that the coal-accumulating basin is of tectonic origin, that the paleogeographic type belongs to the littoral plain and that the coal belongs to humic coal. The microlithotype of the coal is mainly represented by duroclarite. The macerals consist mainly of gelified matrix and, less commonly, fusainized mass. The leptynite components can be only seen in some places. With regard to its metamorphic degree, coals from bituminous to anthracite are all represented. Fat coal-gas, fat coal or fat coking coal are distributed immediately on both sides of the old land. Outwards coking coal-lean,coal-meagre,coal-anthracite appear in succession. According to a study of the coal-accumulating environments,most of the coal deposits are distributed in the clastic flat area of northern Guizhou, confined within the tidal flat-marsh facies of Yingjiang-Dafang-Duyun and Tianzhu-Liping and the beach-flood plain-marsh facies of Weining-Shuicheng. The facies of sandstone with clay rocks or clay rocks with sandstone in the old land or in the gentle slope zones on the margins of submarine uplifts is the best coal-bearing.