鄂北南化地区灯影组碳酸盐台地沉积及层序

本文根据沉积岩相及相组合特征，在鄂北南化地区出露的灯影组碳酸盐岩中自下而上划分出三种主要的沉积相带：蒸发台地、局限台地潮坪和开阔台地泻湖。这一环境演化特征指示相应时期的海平面具有缓慢的上升趋势。层序地层学方面的研究表明，本区灯影组内部可以划分出两个层序，它们代表了晚震旦世晚期本区海平面在总体缓慢上升的背景上，还发生过次一级的波动。这些次级旋回的延续时间（约几千万年）和相应的海平面上升速率（约几十ｍｍ／１０００ｙｒ），表初可能是第２、３级旋回性海平面变化的产物。

CARBONATE PLATFORM DEPOSITS AND STRATIGRAPHIC SEQUENCES OF THE DENGYING FORMATION IN THE NANHUA AREA,NORTHERN HUBEI

According to the features of the sedimentary facies and faCies associations,the carbonaterocks of the Dengying Formation in the Nahua area ,northern Hubei,are divided,from the bot-ton to the top,into three sedimentary facies belts: evaporite platform,restricted platform tidalflat,and open platform largoon. This pattern of environmental evolution indicates a generaltrend of slow sea-level rise. Study of sequence stratigraphy shows that two stratigraphic se-quences can be recognized in the Dengying Formation,and both represent a secondary fluctua-tion on the background of slow rise during the late part of the Late Sinian,The duration（ca.tens of millions of years）and rate（ca. a few of tens of mm/1000 yr）of sea-level rise of eachsecondary to the 2nd-and 3rd-order cyclic sea-level change.