黔渝地区松藻矿区梨园坝井田晚二叠世龙潭组煤系聚煤规律分析

Analysis of coal-accumulating regulation the longtan formation coal series of later permian period in Liyuanba Minefield,Songzao Mining area,Qianyu

根据梨园坝井田勘探资料,初步总结了龙潭组煤层的聚煤规律,运用沉积学、煤田地质学等基本理论和方法,分析了该井田含煤地层的岩性组合、砂体发育特征、古地理、古构造和海水进退等控制因素对聚煤规律的影响.根据含煤地层的岩性、粒度、沉积构造、古生物化石和含硫量等沉积特征,确定了该井田含煤地层形成于局限海碳酸盐台地潮坪沉积体系.结果表明,由古构造引起的海水进退是煤层聚积的主要控制因素,在海退末期海侵初期,地壳相对稳定,可形成强盛聚煤期.泥炭坪是成煤的重要古地理环境,潮沟和潮道的冲刷对煤层有一定的破坏作用.

According to exploration materials of Liyuanba minefield, this paper generalizes the accumulating regulation of Longtan formation, and analyses the effects of the lithologic combinations, sand body developing characters, paleogeography, paleostructure and advancing and retreating of the sea water to the accumulation of the coal seam using sedimentation and coal geology, then determines that the coal-bearing strata were formed in localized sea, carbonate platform and tide flat deposit system according to the sedimentary characters such as lithology, granularity, sedimenta.ry structure, paleobiologic fossil and sulphur content, and so on. It is shown that： the advancing and retreating generated by the paleostructure is the main factor to the coal accumulation; between the terminal phase of regression and the early stage of transgression, the earth crust is relatively stable, and this can form strong coal accumulating phase; the peat flat is an important paleogeographic environment for the formation of the coal; the erosion of the tidal creek and tidal channel have some damage effects to the coal seam.