摘要
始新统平湖组是西湖凹陷的主要含煤岩系,其中蕴含丰富的油气资源。前人对平湖组的沉积环境多有研究,且多数认为其沉积以海相为主。但通过对西湖凹陷西部斜坡带平湖组的岩相、粒度、古生物、地球化学以及测井相等特征进行研究发现该组含煤岩系应为陆相淡水为主的的沉积体系。研究表明,西部斜坡带平湖组沉积时期水体较浅,水体具有振荡的特征;古盐度、地球化学、古生物结合岩相及测井相等特征均显示含煤岩系以还原环境下的湖泊-沼泽相沉积为主,局部区域存在潮汐影响,主力砂体为三角洲平原分流河道沉积;含煤岩系发育受到水体的控制,湖退期发育多套陆相沼泽沉积,是研究区成煤的关键时期。
The Eocene Pinghu Formation is the main coal-bearing rock series with abundant hydrocarbon resources. Many studies have been made on sedimentary environment of the formation;most of them considered the formation mainly belongs to marine facies. But studies on lithofacies, grain size, paleontology, geochemistry and logging facies have found that the coal-bearing rock series in the western slope of Xihu depression should belong to mainly terrestrial fresh water sedimentary system. The study has shown that the water body was shallow with oscillatory features during sedimentation. All paleosalinity, geochemical, paleontological features combined with lithofacies and logging facies have shown the rock series is mainly lacustrine-swamp facies under reducing environment, locally tidal influenced. Main sand bodies belong to delta plain distributary channel deposits. The development of coal-bearing rock series was mainly controlled by water bodies. Many sets of terrestrial swamp deposits have been developed during lake regression, thus the critical period of coal forming.
出处
《中国煤炭地质》
2016年第8期18-25,共8页
Coal Geology of China
基金
国家重大专项课题(2016ZX05027001)
关键词
西湖凹陷
西部斜坡带
平湖组
含煤岩系
沉积环境
Xihu depression
western slope
Pinghu Formation
coal-bearing rock series
sedimentary environment
