冲绳海槽中段沉积岩芯碳酸盐和烧失量的古环境意义

Paleoenviornmental Significance of Carbonate and Loss of Ignition of Sedimentary Cores in the Central Okinawa Trough

对冲绳海槽中段 3个沉积岩芯碳酸盐和烧失量的系统分析得知 ,岩芯沉积物的CaCO3含量一般 >1 0 % ,最高含量接近 30 % ,烧失量大都在 1 0 %～ 30 %之间变化 ,反映了该海区处于溶跃面之上钙质生物极为发育的生物地球化学环境。结合δ1 8O曲线所反映的气候环境变化 ,探讨了 1 2 0kaB .P .以来碳酸盐旋回的“大西洋型”演变特点 ,同时对该区沉积地层中的火山热液活动印记作了一定的探讨。

The systemic analysis of three sedimentary cores sampled in the central Okinawa Trough indicates that the abundance of CaCO 3 is more than 10 percent genernally, the highest abundence can rearch 30 percent, the loss of ignition of these samples ranges from 10 to 30 percent. These data indicate the existence of the biologic geochemical environment located above the lysocline and with higher calcareous organism production in this area. In combination with the climatic chronology reflected by these cores' δ18O curve, we have explored the 'Atlantic' type carbonate cycle's features since 120 kaB.P.. At the same time, we also discussed the volcanogene hydrothermal activity marks in the study area.