山西临汾盆地黄土剖面重金属分布特征及其影响因素

山西临汾盆地2条黄土剖面重金属分布特征及其影响因素研究表明,Pb、Cu和Zn的垂向变化特征非常相似,而As、Cd和Hg在剖面中的分布特征与前三者不同。各重金属元素在黄土剖面中的变化特征首先均受到黄土源区物质成分的控制,其次不同程度地受到古气候变化的影响。依据Pb、Cu、Zn与各古气候替代性指标(例如磁化率,w(SiO2)/w(Al2O3)等)均呈显著相关,As、Cd和Hg与古气候替代性指标的相关性较差,推断剖面中Cu、Pb、Zn的分布特征受古气候变化的影响,其原因可能主要是这3个金属元素易以类质同象形式赋存在磁性矿物中;而As、Cd和Hg在剖面中的分布特征与古气候无关。但各重金属元素与源区指示元素的相关性表明其在剖面中的分布特征均受黄土源区物质成分的影响和控制。

Study of Factors Controlling on Distribution of Heavy Metals in Loess Profiles,Linfen Basin,Shanxi Province

This paper focuses on the distribution features of the heavy metals in loess profiles of Linfen Basin in Shanxi Province,in order to discuss the factors controlling geochemical behaviors of heavy metals in loess soil.The results suggest that Pb,Zn and Cu have similar vertical distribution characteristics.Whereas As,Cd and Hg show different distribution patterns.Pb,Cu and Zn are at variance with paleo-climate indicators such as magnetic rate,SiO2/Al2O3.This indicates that paleo-climate controlled the Pb,Cu and Zn contents in loess.The reason for this is probably that they are in existence as isomorphism of magnetic minerals.As,Cd and Hg contents in loess profiles were not affected by paleo-climate.The relationships between heavy metals and stable elements serve as evidence that their contents in loess reflected the compositions of sources materials of loess.