峡东地区埃迪卡拉系灯影组石板滩段沉积环境探讨

A discussion on the sedimentary environment of Shibantan Member of Dengying Formation in the eastern Yangtze Gorges area

本文通过对峡东地区埃迪卡拉系灯影组石板滩段典型沉积岩的岩石学特征及沉积构造进行详细研究,取得了石板滩段主体沉积形成于台地边缘浅滩-台缘缓斜坡的较多证据,并首次发现了该段地层中保存的十分完整的诸如丘(洼)状交错层理、粒序层理、冲刷-充填构造、渠铸型构造在内的典型的风暴沉积构造。通过对沉积特征、风暴序列的分析认为石板滩段沉积是受风暴作用改造的产物,其主体沉积背景属于正常浪基面与风暴浪基面附近的受周期性风暴影响的台地边缘-台缘缓斜坡环境。

Based on a detailed study of the rock constituents and sedimentary structure of the typical sediments,the authors found that the depositional？environment？of the Shibantan Member of Dengying Formation was a platform edge shallow-platform margin ramp.According to the outcrop sections and the observation,the authors recognized many depositional characteristics of storm deposits,such as hummocky cross stratifications,scouring-filling structures,graded bedding and convolute bedding.The environment of the Shibantan Member of Dengying Formation was influenced by periodic strong waves or storms,occurring below the normal wave base and above the storm wave base.