【摘要】 从钻井岩心、测井、地震、构造沉降和全球海平面变化方面研究了琼东南盆地渐新世崖城组的基准面旋回特征和转换机制.岩心主要用于识别短周期基准面旋回,用岩心标定测井曲线后,可用测井曲线叠加识别出中周期旋回,并据此建立起中短周期基准面旋回的测井模式,可以识别无心井段的基准面旋回.长周期和超长周期旋回则主要利用地震剖面中反映地层不协调关系的上超、下超、削蚀等反射终止类型来识别.在此过程中,岩心、测井与地震三者需要互相验证.文中用地层回剥法恢复了崖城组地层厚度并计算出各凹陷的构造沉降速率为312.5~750 m/Ma.结果表明:崖城组可以划分为1个超长周期、3个长周期和至少12个中周期旋回层序,短周期旋回层序类型发育齐全但数目变化较快.研究区的构造沉降速率远大于全球海平面变化速率(0.2~40 m/Ma),说明基准面旋回的发育和转换受构造沉降的控制程度明显大于全球海平面变化.更多还原

【Abstract】 Based on the data of borehole cores,geophysical loggings,seismic reflections,the characteristics and switch mechanism of base level cycles of Oligocene Epoch Yacheng formation in the Qiongdongnan basin were studied.The lithologies of core samples was used to identify short-period base-level cycles.The logging curves,calibrated with the core data,were used to recognize the mid-period cycles.A template using logging curves to identify the hierarchy of middle and short-period cycles wasestablished,which can recognize the base level cycle in non-coring section.The termination styles of reflections in seismic profile,including onlap,downlap and truncation,which reflect the incompatibility of strata,can identify the long and super long-period cycles.By restoring the thickness of Yacheng formation by a strata-stripping method,the tectonic subsidence rate of each sag of 312.5-750 m/Ma was achieved.The results show that the Yacheng fromation can be subdivided into 1 super long period,3 long period and at least 12 mid-peroiod cycle sequences.The short-period cycle types are complete,but their number varies largely in different locations.The tectonic subsidence rate was much higher than the global sea-level change rate of 0.2-40 m/Ma,which show that the development of base-level cycles and switch mechanism in this area were controlled more obviously by tectonic subsidence than by global sea-level change.更多还原