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含煤岩系为上三叠统(T_3l)及下侏罗统(J_1m),由中—细粒砂岩、粉砂岩、泥岩夹薄煤层组成。根据粒度分析结果,可知砂岩的粒度概率图主要属河流及浅湖型。煤系中见水平层理、沙纹层理、大型交错层理、平行层理及块状层理,它们常构成特定的垂向序列。煤系内产丰富的植物化石,属热带—亚热带植物群。 相分析表明:煤系属大陆河流及湖泊沉积,沉积类型有冲积扇、辫状河、曲流河、河漫滩、湖泊、沼泽等。T_3l以湖泊沉积为主,而J_1m则以河流相为主。 作者根据该区古构造格局及古地理环境指出,煤层主要产于河漫滩沼泽及浅湖沼泽中,聚煤有利地区在无为县石罗山、昆山至枞阳县小含山一带。
The coal-bearing rocks are Upper Triassic (T_3l) and Lower Jurassic (J_1m) and are composed of medium-fine sandstone, siltstone and mudstone with thin seam. According to the results of particle size analysis, we can see that the particle size probability maps of sandstone are mainly rivers and shallow lakes. In the coal system, horizontal bedding, sandy bedding, large-scale staggered bedding, parallel bedding and massive bedding often form specific vertical sequences. Coal is rich in plant fossils, a tropical - subtropical flora. The phase analysis shows that coal belongs to the continent rivers and lakes, and sedimentary types include alluvial fan, braided river, meandering river, floodplain, lake and swamp. T_3l is dominated by lake sediments, while J_1m is dominated by river facies. According to the ancient palaeogeomorphology and palaeogeographic environment in the area, the authors point out that the coal seam is mainly produced in floodplain swamps and shallow lakes and swamps. The advantageous areas for coal accumulation are Shiluoshan in Wuwei County and Xiaoshan Mountains in Kunshan to Zongyang County.