重庆永川地区二叠系龙潭组聚煤环境研究

Research on Coal-accumulating Environment in Longtan Formation of Permian in Yongchuan Area of Chongqing

通过大量钻井岩心观察、野外地质剖面测量、矿区煤田地质调查及室内样品测试分析,结合大量区域及前人研究成果,对重庆永川地区二叠系龙潭组聚煤环境进行研究。龙潭时期主要沉积环境为局限海湾中的潮坪亚相(龙潭早期)和泻湖亚相(龙潭晚期)。在潮坪亚相中,潮上泥炭沼泽和潮间泥炭坪是主要的聚煤环境。煤层形成的厚度往往决定于泥炭的沉积速率和海平面变化速率,后者在一定时期内保持平衡时,厚度往往较大,同时层位稳定,连片性好。潮间泥炭坪中的煤层随海平面的变化,具明显的迁移性,煤层发育相对较差。

Based on core observation, measurement of geological profile in field, geotogical survey in coalfield and testing analysis of samples indoor, coal-accumulating environment in Longtan formation of Permian in Yongzhou area of Chongqing is researched with many previous research achievements. Sedimentary circumstance in early time of Longtan was limited gulf tidal flat sub-face, and lagoon subface was developed later. Peat moor in supratidal fiat and turfy intertidal flat are main coal- accumulating environment in tidal sub-face. Thickness of coal beds is large when sedimentary velocity is in equilibrium with changing rate of sea level, and coal horizon is easy to trace with good continuity. But coal bed in turfy intertidal fiat is migrated with the change of sea level, and coal horizon is hard to trace with bad continuity.