Recent Sedimentation Dynamics Indicated by 210Pbexc and 137Cs Records from the Subtidal Area of Bohai Bay, China
Recent Sedimentation Dynamics Indicated by 210Pbexc and 137Cs Records from the Subtidal Area of Bohai Bay, China
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DOI：
10.2112/jcoastres-d-15-00074.1
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发表时间：
2016-03
影响因子：
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通讯作者：
Fu Wang;Y. Zong;Jian Fen Li;L. Tian;Z. Shang;Yongsheng Chen;Xingyu Jiang;Ji Long Yang;Biao Yang;Hong Wang
中科院分区：
文献类型：
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作者：
Fu Wang;Y. Zong;Jian Fen Li;L. Tian;Z. Shang;Yongsheng Chen;Xingyu Jiang;Ji Long Yang;Biao Yang;Hong Wang
摘要王福；宗永庆；李建峰；田林中；尚志伟；陈永生；姜晓云；杨俊林；杨宝斌，王海东，2016。渤海湾潮下带的~(210)Pbexc和~(137)Cs记录所反映的现代沉积动力学，中国。为了确定渤海湾西岸开阔海域的沉积速率变化，采集了50多个短沉积岩芯，并用沉积物中过量的210Pbexc和137Cs估算了它们的沉积速率。这些调查使我们能够探索河流泥沙供应变化与浅海地区时空沉积模式之间的关系。一些岩心记录表明，仅基于210Pbexc曲线的常规恒定初始浓度模型可能会高估沉积速率。高估是由于这些岩心顶层210Pbexc的变化引起的，通过将210Pbexc曲线与各自的137Cs曲线进行比较，证实了这一点。这一现象可能是由于沉积物侵蚀或表层沉积物在海底重新沉积造成的，这意味着由于过去50年来自河流的沉积物供应急剧减少，今天的沉积过程活跃。根据河流流量资料，沉积速率变化的沉积边界与供沙量变化的时间有很大的可比性，可以作为沉积速率对比的局部时间标志。
ABSTRACT Wang, F.; Zong, Y.Q.; Li, J.F.; Tian, L.Z.; Shang, Z.W.; Chen, Y.S.; Jiang, X.Y.; Yang, J.L.; Yang, B., and Wang, H., 2016. Recent sedimentation dynamics indicated by 210Pbexc and 137Cs records from the subtidal area of Bohai Bay, China. To determine sedimentation rate changes across an open marine area along the west coast of Bohai Bay, more than 50 short sediment cores were collected and analyzed with their sedimentation rates estimated by excess 210Pb (210Pbexc) and 137Cs in the sediment. The surveys enabled us to explore the relationship between sediment supply changes from the rivers and the spatial/temporal deposition patterns in the shallow marine areas. Several core records show that sedimentation rates can be overestimated by the conventional constant initial concentration model based on the 210Pbexc curves alone. The overestimation was caused by a change of 210Pbexc in the top layers of these cores and this is confirmed by comparing 210Pbexc curves with the respective 137Cs curves. This phenomenon is likely caused by sediment erosion or redeposition of the surface sediment at the seabed, implying present-day active sedimentary processes as a result of the drastic decrease in sediment supply from the rivers during the last 50 years. The sedimentary boundary where sedimentation rate changed is largely comparable with the timing of sediment supply change according to the river discharge data, which can be used as a local time marker for sedimentation rate comparison.