THE DISTRIBUTION AND THE MIGRATORY LAW OF THE COAL ACCUMULATIVE BELT IN ERDOS BASIN

摘要

The formation of the coal-rich belt or the coal-rich unit needs the special geologic condition that includes the fine cooperation of the paleo-vegetation, the paleo-structure, the paleo-climate and the paleo-geography. In it's involution, the Erdos basin underwent many kinds of the sedimentary environment which control the formation of the coal. The alternation of the sedimentary systems and the system tracts in the space is the important event in the filling of the basin. So the law of the coal-accumulating is different in the different stage of the basin, and the distributing feature of the coal-rich belt and the coal-rich unit are different. Coal is the most important energy sources of the Erdos basin formed in the Paleozoic and Mesozoic. Three sets of the coal-series of the Permian-Carboniferous, the Trias and the Jurassic developed in the Erdos basin. The coal beds formed in Permian-Carboniferous are the thickest one in the west, and the thickness is more than 20 meters; the east takes second place, the thickness is 10 meters. The coal beds in south and north are more thinner. The coal bearing series of Trias is dominated by WaYaobao formation. The coal bearing area is limited in Huangling, Fuxian, Zichang, Yan'an and Zizhou. And the thickness of the coal in Zichang can be mined. The numbers of the coal beds are 7 to 15, but only one bed can be mined whose thickness is 1 to 2 meters. The thickness of the coal series of Jurassic is general more than 10 meters in Yikezhaomeng in the north of the basin, and is more than 5 meters in the west of Dingbian and Qingyang, and is more than 0.8 meter in the southern part of Qingyang and Fuxian. In the opinion of the geologic time, the coal accumulation of Erdos basin is controlled by the tectonics. In Paleozoic, the coal-accumulative background of the basin is similar to the north of China. Both of them are the epicontinental basin in the unite plate. In Mesozoic, the feature of the basin has changed thoroughly. The Erdos basin has become into a coal forming basin of terraneous fades of large scale. At the same time it is a basin bearing the oil and the gas. The intensity of the coal-accumulative action is different in the different evolutive stage. The feature of the coal formation is different too. For example, the coal beds which was formed by the accumulation in the foreign place. The coal-rich belts migrated constantly, and the law of the migration is more important to the intergrowth and the coexistence of many kinds of the mineral resources in the basin. Because it has offered a lot of source rocks and at one time it is the main storage of the coal gas. The coal-rich belts commonly develop on the slope of the basin, and they have the correlativity with the sand-body in the cause of formation. While the sand-body is also the saving carrier of the oil and gas, and the Uranium of sandstone type. So the acknowledgement of the coal-rich belts is helpful to the forecast of the oil and gas, and the Uranium of sandstone type.