标题:
川东奉节及周缘地区下三叠统飞仙关组沉积特征及相带演化The Sedimentary Characteristics and Facies Evolution of the Lower Triassic Feixianguan Formation in Fengjie and Its Peripheral Areas in the East Sichuan Region
作者:
腾飞, 胡忠贵, 刘忠保, 蔡家兰, 左洺滔
关键字:
沉积特征, 相带演化, 飞仙关组, 奉节地区Sedimentary Characteristics, Evolution of Facies Belt, Feixianguan Formation, Fengjie Area
期刊名称:
《Journal of Oil and Gas Technology》, Vol.38 No.4, 2016-12-15
摘要:
根据野外剖面观察和室内镜下岩石薄片鉴定分析，结合最新钻井资料，以岩石学、古生物及地球物理解释成果为基础，确定研究区早三叠世飞仙关组早期的孤立碳酸盐台地模式和晚期的连陆碳酸盐台地模式，细分为局限台地、开阔台地、台地边缘浅滩、台地前缘斜坡和陆棚/盆地等沉积相类型。通过关键层序界面识别，将飞仙关组划分为2个三级层序和5个四级层序，建立了四级层序地层格架。层序格架内沉积相演化规律表明，飞仙关期，自早期到晚期水体逐渐变浅，发生充填补齐的沉积作用，奉节地区沉积格局逐渐由开阔台地–台地边缘–前缘斜坡–海槽相过渡为局限台地–开阔台地，至飞仙关晚期完全准平原化为局限台地潮坪沉积。
According to the observation of field profile and the laboratory analysis of thin sections, combined with the latest drilling data and based on the results of petrology, paleontology and geophysical interpretation, it was determined that in the earlier Feixianguan Formation of Lower Triassic there existed the isolated carbonate platform mode and the latter period of the land carbonate platform, and it was subdivided into the sedimentary types of restricted platform, open platform, shoal on the platform margin, platform fore-slope, shelf/basin and so on. According to the identification of key sequence boundaries, the Feixianguan Formation in the study area was divided into 2 third-order sequences and 5 fourth-order sequences, and a fourth-order sequence stratigraphic framework was established. The law of sedimentary facies evolution in sequence framework shows that the water body becomes shallow gradually from the Earlier Period to the Latter Period of Feixianguan Formation, and in this period, the filling in sedimentation appears. The sedimentary framework of Feixianguan Formation in Fengjie Area is transitioned from open platform- platform margin-platform fore-slope-shelf sedimentation zones to the restricted platform-open platform, and in the latter period of Feixianguan Formation it becomes a tidal flat sediment of restricted platform caused by complete quasi-plain.