东海陆架晚第四纪沉积硅藻及其古海洋学意义

Late Quaternary sedimentary diatom from East China Sea continental shelf and its paleoceanographical significance

本文对东海陆架DG961 7岩芯沉积硅藻进行了研究 ,共分析鉴定出 97种和变种 ,有近 1 0种硅藻在岩芯中连续分布 ,且有较高的含量 ,而其余种类含量极低 ,仅零星检出 .根据该岩芯中产出硅藻种类、含量及硅藻丰度变化特征自下而上共划分出 3个硅藻组合带及 5个亚带 .结合孢粉资料 ,对产出 3个不同硅藻带岩芯的地层年代进行了对比研究 ,表明该岩芯所代表的地层年代为中 晚全新世 ,硅藻Ⅰ组合带大致为大西洋期的沉积 ,硅藻Ⅱ组合带应为亚北方期的产物 ,而硅藻Ⅲ组合带与亚大西洋期对应 .文中并对不同硅藻组合带产出时的古海洋环境进行了初步探讨 .

Sedimentary diatoms of core DG9617 from the continental shelf of the East China Sea are studied in this paper. 97 diatom species and varieties are identified, among them nearly 10 diatom species distribute continuously in the core with higher relative contents, but others distribute scatteredly with very lower relative contents. 3 assemblage zones and 5 assemblage sub-zones are subdivided based on the characteristics of the species composition, the relative contents and the abundance of the sedimentary diatoms. Stratichronology study of these 3 diatom assemblage zones combining to the analysis data of palynology from the same core suggests that the age of the core belongs to middle and late Holocene. The first diatom assemblage zone represents the sediment of Atlantic Period, the second of the Sub-boreal Period and the third of the Sub-Atlantic Period. The paleoceanographical environment of the East China Sea continental shelf in late Quaternary is also discussed according to the characteristics of diatom assemblage zones.