摘要
东海陆架盆地是位于中国大陆东部边缘大陆地壳之上的边缘海盆地。盆地新生代构造演化经历了断陷(初始沉降)和坳陷(热控沉降)两个阶段。本文利用钻井及地震反射剖面资料,通过钻井古地层剥蚀量和剥蚀时间的恢复,应用Mckenzie(1978)的均一拉伸模式和Sclater(1985)的双层拉伸模式对陆架盆地,主要是浙东坳陷的西湖凹陷进行了基底沉降和地壳岩石圈扩张率的定量估算。计算结果表明东海陆架盆地沉降速率早期较快,后期变慢。西湖凹陷新生代以来地壳岩石圈扩张率,在凹陷北部(D800测线)为40%—50%,中部(D688测线)为100%—140%,南部(G455测线)为60%—120%
The East China Sea Shelf Basin is a marginal sea basin located on Continental crust of China eastern margin. The formation and evolution of the basin have been controlled by the interaction of the Eurasian,Indian, and Pacific plates. The Cenozoic evolution of the basin underwent two stages of fault controlled subsidence and thermal subsidence. Their geological framework is tectonically characterized by zonation from west to east and blocks from south to north. From west to east tectonics, faults, and depositional faces become younger. The transition from fault controlled subsidence stage to thermal subsidence stage took place at the early Eocene in the western part of East China Sea Shelf Basin, and at the late Eocene in the eastern part. By using the drilling data and seismic reflection profile data, this paper analyzes Cenozoic tectonic evolution of East China Sea Shelf Basin (mainly for Xihu sag of Zhedong depression) by using uniform lithosphere extension model and two layer extension model. The effect of eroding amount and ages of late tectonic event have been considered in the processes of calculation. The result of calculation show that the rate of subsidence was relatively large at the early stage and relatively small at the late stage. Since Tertiary the rate of crustal stretching at Xihu sag of Zhedong depression was 40—50% in the northern part (D800 measurement line), and 100—140% in the middle part (D688 measurement line), and 60%—120% in the southern part (G455 measurement line).
出处
《地质科学》
CAS
CSCD
北大核心
1999年第1期29-39,共11页
Chinese Journal of Geology(Scientia Geologica Sinica)
关键词
东海
陆架盆地
断陷阶段
基底沉降
扩张率
East China Sea Shelf Basin, Fault controlled subsidence stage, Thermal subsidence stage, Basement subsidence, Rate of crustal stretching