| 摘要: |
| 过剩210Pb不仅是沉积物年龄测定的重要手段,而且是环境示踪的一种主要方法.干旱区湖泊主要为封闭湖泊,其沉积物所接受的过剩210Pb沉积在大气沉降背景外,主要受风沙侵蚀来源的影响.因此,较高的过剩210Pb沉积通量有可能与区域风沙活动有关.本文在对比分析近几年来发表在各期刊中的湖泊210Pb数据的基础上,计算各个湖泊多年平均过剩210Pb的沉积通量并与大气过剩210Pb沉降背景比较,从而初步确定中国北方干旱区风沙活动的可能区域.然后对所确定的典型风沙多发区,利用过剩210Pb模式(PF-CRS)计算沉积物沉积速率,并与相应区域的"尘暴"记录对比,进而论证该方法在指示风沙活动方面的可靠程度. |
| 关键词: 干旱区 湖泊沉积物 Pb-210沉积通量 沉积速率 风沙活动 |
| DOI：10.18307/2009.0610 |
| 分类号: |
| 基金项目:国家重点基础研究发展计划(973)项目“北方干旱化与人类适应”子课题“北方干旱化进程中的阶段性转折和突变及其可预测研究”(2006CB400503)资助 |
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| Preliminary study on excess210Pb flux characteristic of lake sediment in arid regions and its implication for aeolian activity |
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CHEN Yongfu1, ZHAO Zhizhong2
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1.Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, P.R.China;2.Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, P.R.China
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| Abstract: |
| Excess210Pb dating is not only an important method for sediment dating, but also a major environmental tracer. In aridregions, excess210Pb deposited in lake sediment mainly depends on wind erosion recycle besides the atmospheric precipitation fluxbackground. Therefore, the higher excess210Pb is a potential for identifying the aeolian activities. This paper makes a systematicalanalysis on the data published in recent years, and calculates the multi-year average excess210Pb flux in different lakes. Thus, the areasin which multi-year average excess210Pb flux that exceeded atmosphere flux background could be recognized preliminarily as regionalaeolian deposits. And then, we use the excess210Pb model (PF-CRS) to calculate the lake sedimentation rates in some typical aeolianregions. At last, we compare the results with the dust records correspondingly so as to estimate the reliability of this method. |
| Key words: Arid regions lake sediment Pb-210 flux sedimentation rates aeolian activities |
