华北板块晚古生代古气候变化对聚煤作用的控制

Control of Palaeoclimatic Change on Late Palaeozoic Coal Accumulation of the North China Plate

在研究了华北板块晚古生代煤炭资源的地质地理分布基础上,对生态域和其他具古气候含义的地质记录的综合分析表明,该板块的煤为无季节性分化的热带雨林气候条件下的产物。由于二叠纪的全球性升温事件和热带—亚热带干旱带向低纬度扩张以及华北板块的向北漂移,使得晚石炭世—亚丁斯克期早期广泛存在的聚煤作用,在亚丁斯克期晚期—卡赞期收缩至该板块的东南一隅。

There are about 1494 billion tons of coal resources in the North China plate in the Permo-Carboniferous rocks, of which about 94. 9 percent occur in the Kasirnovian to lower Artinskian Stages. The exploitable coal seams are well developed in the whole basin covering most of this plate. By contrast, about 76. 2 billion tons of upper Artinskian to Kazanian coal resources are only restricted to the southeastern part of the plate. Based on analyses of the biomes and other geological records with climatic implications, all Permo-Carboniferous coals in the plate were formed by primary peats under the tropical rain forest climate. Palaeomagnetic evidence shows that the North China plate, as an independent block in the east Tethys, continuously drifted northwards from the equator to middle latitudes in the Northern Hemisphere from the Late Carboniferous to Permian. During the Kasirnovian to early Artinskian, the plate was located in the climatic zone of the tropical rain forest between the equator and the 20°N latitude, which was favourable for coal formation. Following the rise of temperature and expansion of the arid zone to the equator as well as the continuous northward movement of the plate during the Permian, climate differentiation took place in the plate during the later Artinskian to Kazanian. The main part of the plate was separated away from the hot and wet climate zone of the tropical rain forest and west into the savanna and hot arid climate zones where coal was difficult to form. In this way,the later Artin skian -Kazanian coal resources are restricted to the southeastern corner of the North China plate. which was still located in the climate zone of tropical rain forest.