长江水下三角洲YD0901孔记录的全新世以来的古环境信息

The paleoenvironmental information of core YD0901 in the subaqueous Yangtze River delta since Holocene

摘要:

对长江水下三角洲YD0901孔粒度、TOC和TN分析，建立了全新世以来高分辨率年代地层（平均分辨率为20a）。结果显示，“中全新世大暖期”(6~7ka)水下三角洲加速营造，同时闽浙泥质区开始缓慢形成。TOC和TN测试数据表明：2.7kaB.P.左右，YD0901孔的TN含量逐渐增加，说明流域人类活动逐渐加剧。而TOC由于部分发生成岩作用，其含量并未明显增加。通过沉积相分析得到最大海侵面MFS的深度，为准确估算冰后期最大海侵以来水下三角洲沉积总量提供了可靠的依据。

Abstract:

Based on grain size, TOC and TN analyses of core YD0901, located in the subaqueous Yangtze River delta, we establish the Holocene high-resolution chronostratigraphy. The results show that the subaqueous delta was formed rapidly during 6~7ka (the Middle of Holocene Warm Period). Meanwhile, the mud areas of Fujian and Zhejiang were formed slowly. TOC and TN test data show that the content of TN increases around 2.7kaB.P., indicating the gradual increase of human activities in Yangtze River Basin. However, the content of TOC has not increased significantly because of the diagenesis. And the depth of MFS (34.22m) provides a reliable basis about the accurate estimation of the total amount of subaqueous delta since the post-glacial Maximum transgression.