川东北元坝地区长兴组-飞仙关组碳酸盐台地边缘沉积特征及演化

Sedimentary characteristics and evolution of the carbonate platform-margins in the Changxing Formation-Feixianguan Formation in Yuanba,northeastern Sichuan

川东北元坝地区长兴组-飞仙关组碳酸盐岩台地边缘以生物礁滩和鲕粒滩沉积为特征:台地边缘最初在吴家坪晚期出现,在经历了长兴期台地边缘礁滩的形成和消亡、印度早期台地边缘鲕粒滩形成和消亡两个阶段的演化后,最终在印度晚期被填平补齐。碳酸盐岩台地边缘演化受到包括地形的几何形态、水动力条件、沉积速率及空容纳空间增长速率的控制。

The carbonate platform-margin deposits consist of organic bank and oolitic bank deposits in the Changxing Formation-Feixianguan Formation in Yuanba,northeastern Sichuan.The carbonate platform-margins went through the evolution from the initiation of the platform margins during the late Wujiapingian,through the development and termination of the platform-margin reefal bank during the Changiangian,to the development and termination of the platform-margin oolitic bank during the early Indian,and finally to the filling of the platform margins during the late Indian.The controlling factors include topography,hydrodynamics,depositional rates and increasing rates of accommodation spaces,all of which have consequences for lithology and the styles of the accumulation and migration of the platform-margin deposits.