东海陆架与冲绳海槽晚第四纪沉积硅藻的对比研究

Contrast Study on Late Quaternary Sedimentary Diatoms Between the Okinawa Trough and the East China Sea Shelf

通过对东海陆架DG9617孔以及冲绳海槽A孔和B孔岩芯沉积硅藻进行高分辨率的采样分析,总共鉴定出166种和变种,其中有近14个主要硅藻种在3个钻孔中都连续分布,且有较高的含量,而其余种类含量较低或分布不连续或仅零星检出.根据3个钻孔岩芯中产出硅藻属种组成、含量变化及热带远洋种丰度等特征建立起各自的硅藻组合带.通过对比分析,表明硅藻植物群在东海陆架及冲绳海槽不同沉积环境条件下均记录了自晚第四纪以来古海洋、古气候的变化.

Sedimentary diatoms of Core DG9617 located at the East China Sea continental shelf and Core A and Core B located in the mid margin of Okinawa Trough are studied.166 diatom species and varieties belonging to 52 genus are identified,among which about 14 species are continuously distributing with high content in the three cores,such as Actinocyclus ehrenbergii,Actinoptychus splendens,Act.undulates,Coscinodiscus decrescens var.valida,Cos.nodulifer,Cos.perforatus,Cos.blandus,Cos.radiatus,Cyclotella stylorum,Melosira sulcata,Rhaphoneis surirella,Rhizosolenia bergonii,Thalassiosira excentricus and Tryblioptychus cocconeiformis,but the others including Cos. africanus,Cos.centralis,Cos.lineatus,Diploneis bombus,D.weissflogii,Nitzschia cocconeiformis,Rhaphoneis amphiceros,Thalassionema nitzschioides,Triceratium favus and T.reticulum are rarely appearing or with low content.Sedimentary diatom assemblage zones are subdivided and their characteristics are contrasted in these three cores based on the diatoms species composition,the relative contents change and the characteristics of pelagic species.The ocean environment and palaeoclimate variation can be recorded by the sedimentary diatoms florae in the East China Sea continental shelf same as in the Okinawa Trough during the late Quaternary.