闽西南龙永煤田童子岩组沉积地层精细特征与沉积环境演化分析  

Sedimentary characteristics and sepositional environment analysis of the Tongziyan Formation in Longyong coalfield, southwestern Fujian Province

作　　者：许福美[1] 吴传始[1] 郭玉森[1] 吴志杰[1] 

机构地区：[1]龙岩学院资源工程系,福建龙岩364012

出　　处：《地质科学》2011年第2期570-584,共15页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：福建省自然科学基金项目(编号:2008J0244)资助

摘　　要：运用沉积学、古生物地层学、层序地层学、岩石粒度分析等方法,从岩性特征、沉积构造、沉积体系等方面对研究区童子岩组地层的沉积特征进行了详细的研究,对其沉积环境演化特征进行分析。结果表明:研究区的童子岩组地层主要由较细粒的陆源碎屑物质组成,在整个童子岩组第一段发育过程中,障壁岛及其背后的整个环境组合随着区域海平面的升降而前后移动,反映了高级别的海水进退过程。童子岩组第三段的下亚段主要为障壁岛—潟湖环境,煤层具有厚薄相间分布的特点,反映了障壁岛后沉积地形的复杂性,为海退过程;中亚段为障壁岛后潟湖环境,含煤性好,随后潮汐作用成为主要控制因素,广泛发育了潮坪、潮道沉积;上亚段由于进一步的海退,演变为滨岸湖泊环境。将童子岩组地层主要海侵事件的初始面作为成因地层单元的划分界线,把本区童子岩组划分为3个沉积旋回,11个成因地层单元(相序),沉积体系可划分为障壁岛—潟湖沉积组合、潮坪—潮道沉积组合和滨岸湖泊沉积组合,每一组合由若干沉积相组成;其沉积环境演化可划分为早期、中期和晚期3个阶段,与童子岩组第一段、第二段和三段地层形成时期相对应。By using sedimentology ,paleontology and sequence stratigraphy ,rock particle size analysis and other methods,the detailed sedimentary characteristics of Tongziyan Formation in Longyong coalfield has been studied in the aspectes of lithology, sedimentary structures, depositional system. The results showed that the Tongziyan Formation is mainly composed of fine-grained lithic quartz sandstones and quartz sandstones with different types of beddings, such as the small plate and trough cross beddings, ripple waves and cross beddings, hummocky cross beddings, climbing ripple beddings, graded beddings, horizontal beddings, veins, wavy and lenticular beddings, etc. There are abundant marine fossils in this formation, including brachiopods,bivalves, cephalopods and dragonflies, together with some terrestrial plant fossils of ferns and seed ferns. According to sequence stratigraphic analysis, the Tongziyan formation in this district can be divided into three sedimentary cycles, 11 genetic stratigraphic units（phase sequence）. Generally, Tongziyan Formation is formed in the littoral depositional environments of barrier island-lagoon and tidal fiat-tidal channel lake shore which can be further divided into a number of different sedimentary facies according to its sedimentary assemblages. The evolution of the sedimentary environments of Tongziyan Formation can be divided into three phases： early, middle and late periods.

关 键 词：龙永煤田 童子岩组 岩矿特征 地球化学特征 沉积特征 

分 类 号：P534[天文地球—古生物学与地层学] P591[天文地球—地质学]