| 摘要: |
| 为了评价青海湖流域土壤的环境背景值，2008~2009 年分别采集流域表层土壤样品共
273 个，采用X 荧光光谱仪分析了29 种元素（Na、Mg、Al、Si、K、Ca、Fe、P、Ti、V、Cr、
Mn、Co、Ni、Cu、Zn、Ga、As、Rb、Sr、Y、Zr、Nb、Ba、Pb、La、Ce、Nd 和 Th）的含量，
根据ArcGis 地统计工具ESDA 模块，确定了表层土壤背景值及其范围。结果表明：总体上青海
湖流域表层土壤各元素含量偏低，但Ca 元素含量明显偏高，Zn 元素含量明显偏低；流域风化程
度是初等风化脱Ca、Na 阶段向中等风化脱K 阶段转变，风化环境处于冷干向暖湿转变，风化的
主控因素是母岩和温度；大多数元素含量的变化都与沉积物中粘土（<4 μm）含量的变化呈一致
性，而与砂（>63 μm）的含量变化呈反相关关系，这些元素多赋存在细颗粒物中，少部分元素容
易赋存于粗颗粒中；常量元素的活动性的顺序为：K2O ＞ CaO ＞ SiO2 ＞ MgO ＞ Na2O ＞ Al2O3
＞ TiO2 ＞ P2O5 ＞ Fe2O3 ＞ MnO；微量元素的活动性的顺序为：Ni ＞ V ＞ Pb ＞ Ba ＞ Sr ＞ Zr
＞ Ce ＞ Rb ＞ Co ＞ Zn ＞ La ＞ Y ＞ Nd ＞ Cu ＞ Th ＞ Nb。 |
| 关键词: 元素 表层土壤 环境背景值 青海湖流域 青藏高原东北部 |
| DOI：10.7515/JEE201003006 |
| CSTR： |
| 分类号:X820.1 |
基金项目:国家“十一·五”科学与技术支撑项目(2007BAC30B01)
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| Environmental background values and its impact factors of topsoil within the Lake Qinghai catchment, NortheastTibetan Plateau, China |
|
WANG Ping1,2, CAO Jun-Ji1, WU Feng1
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1.State Key Lab of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, xi'an
710075, China; 2. Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
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| Abstract: |
| In order to evaluate the soil environmental background values , a total of 273 topsoil samples
were collected from Qinghai Lake watershed in 2008-2009, northeast Tibetan Plateau. 29 elements
(Na, Mg, Al, Si, K, Ca, Fe, P, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Y, Zr, Nb, Ba, Pb, La, Ce,
Nd and Th) were determined by the XRF. The environmental background values and its scope were
evaluated with Explore Spatial Data Analyst (ESDA) of Geostatistical Analyst in ArcGis 9.3. In contrast
to the background levels of trace elements for China topsoil , the contents of each element was low, Ca
content was obviously higher and Zn was evidently low. The soil was in a transit stage during the course
of chemical weathering, i.e., large amount of leachable Ca2+, Na+ accompanying with deepen dilution
trend of K+. The environment of chemical weathering in Qinghai Lake soil was in a stage toward warm
and humid climate from cold and dry climate. Bedrock and temperature are main controlling factors for
chemical weathering. Variations of the contents of major chemical elements in topsoil were consist with
the variation of the percentage of clay fractions (<4 μm) in sediments, but were anti-correlated to those
variations of sand fractions (>63 μm). These chemical elements easily existed in fi nd grain particles and
little elements in coarse particles. The activity sequence of major elements and trace elements are:K2O>CaO>SiO2>MgO>Na2O>Al2O3>TiO2>P2O5>Fe2O3>MnO, Ni>V>Pb>Ba>Sr>Zr>Ce>Rb>Co>Zn>
La>Y>Nd>Cu>Th>Nb, respectively. |
| Key words: elements topsoil environmental background values Qinghai Lake catchment Northeast
Tibetan Plateau |
