向海湿地元素地球化学特征与高分辨沉积记录

以内流河下游漫流区-向海沼泽湿地为研究对象,对其典型剖面沉积物的柱状样以厘米级间距采样,在多元统计分析的基础上,结合¹³⁷Cs、²¹⁰Pb测年数据对其进行高分辨率元素地球化学特征解析,以获取现代沉积记录及其与流域环境变化的关系。结果表明,主成分分析提取的第一主成分有较高的代表性;聚类分析将元素按造岩、迁移累积型、强烈迁移型元素归为三类;大多数金属元素之间存在着显著相关性,并且均与TOC、<63?μm粒径的颗粒呈正相关。典型剖面金属元素的高分辨沉积记录解析表明:向海的沼泽发育可以追溯至1885年之前;1885年左右区域环境发生过突变;近250年以来,暖湿气候与风沙、干旱交替出现;研究区沼泽湿地沉积物表层沉积序列内已明显富集了重金属元素,近年霍林河流域上游人类活动对下游湿地的扰动增强。

Characteristics of Element Geochemistry and High-resolution Sedimentation Records in Xianghai Wetlands

Here we reported a case study on the Xianghai wetlands at downstream of an interior river—Huolin River. By segmenting sample at an interval of 2cm or 4cm and assorted with ¹³⁷Cs,²¹⁰Pb age measure, high-resolution characteristics of sediment element geochemistry were analysed in two typical sedimentation cores. Results indicated that F1 of PCA has much more representative; Cluster Analysis classifies elements to three major groups according to geochemistry features and behavior at surface of the earth; most of metal elements present remarkable relativity among them and with TOC and <63?μm grain size, by analyzing high-resolution sedimentation records, Xianghai marsh development can be traced back to 1885; in 1885 AD, the environment in this region have originated sudden change; in recent 250 years, temperate and humid climate, wind-drift sand action, or arid climates have occurred by turns; within the upper layers of the sedimentary sequences, heavy metals have been enriched clearly, which indicated increasing human disturbance in the upper reaches of the Huolin River.