南海北部大陆架莺琼盆地新生代海平面变化

南海北部大陆架莺琼盆地是建立西太平洋新生代海平面变化的关键地区之一。基于有孔虫和钙质超微化石资料所建立的莺歌海盆地和琼东南盆地新生代相对分辨率较高的年代地层格架,通过南海海域表层建立的浮游有孔虫含量与水深的定量关系,辅以古生态、成因相及特征沉积构造分析和反射地震剖面的海岸上超分析,编制了海平面变化曲线。识别出包含三个完整二级海平面变化旋回和半周期的海平面上升旋回。海平面变化幅度在0～200 m之间。海水最深的时期在早中新世晚期至中中新世早期以及上新世早期,与Haq曲线较为吻合。

The Cenozoic Sea-Level Changes in Yinggehai-Qiongdongnan Basin,Northern South China Sea

The Yinggehai-Qiongdongnan(Ying-Qiong) Basin is a part of the South China Sea Shelf Basin.It is the key area to set up the Cenozoic sea level change cycles in west Pacific Ocean.Based on a relative high-resolution chronostratigraphic framework which formed from the data of foraminifera and Calcareous nannofossils,the curves of Cenozoic sea level changes in Ying-Qiong Basin was reconstructed according to the quantitative relationship between the percentage of pelagic foraminifera and water depth in the surface layer of South China Sea and by the analysis of the paleoecology,the geneses phase,the characteristics of sedimentary structures and the coastal onlap recognized in seismic reflection profiles.Three integrated 2nd-graded cycles of sea level changes and a half period cycle of sea level rising was set up from Oligocene to nowadays.The sea-level changes ranged between 0m and 200m.The deepest water appeared from the late Early Miocene to the early Middle Miocene.Compared with the Haq’s curve(1988),the curves are similar in long-term and high order cycle of sea level changes.Xie Jinyou,Zhu Youhua,Li Xushen,Mai Wen,Zhao Pengxiao