在我国海岸沙丘主要分布地区河北昌黎黄金海岸选取代表性的海岸横向沙脊为研究对象,对其典型断面上沙丘表面不同部位的21种地球化学元素的含量进行了比较分析。结果表明,Co、Zr和Mg三种元素在海岸沙脊表面不同部位的含量差异明显且与海滩沙相比含量差异较大,Cr、Pb、Ti、Nb、As、Mn、Zn和Ba等8种元素的含量差异程度中等,但Y、Ca、Fe、Na、Al、Sr、P、K、Rb和Si等10种元素的差异并不明显,而11种差异程度中等以上元素在海岸横向沙脊迎风坡脚、迎风坡、脊顶、背风坡、背风坡脚等部位的含量变化特征并不一致,呈现出不同的分异模式,其主要原因是受沉积环境、化学元素性质、粒度特征及营力的影响等。
Taking a typical coastal Aeolian transverse ridge at Changli Gold Coast in Hebei province as an example,which is one of the most typical coastal aeolian distribution regions in China and famous for the tall and typical coastal transverse ridges,the distribution characteristics of 21 kinds of geochemical element in the modern aeolian sands on the surface of coastal aeolian dune(coastal Aeolian transverse ridge)are analysed.The research results show,in 21 geochemical elements which are contained in the modern aeolian sands on the surface of coastal aeolian transverse ridge,the differentiations of three geochemical elements at different sites over the surface of coastal dune are obvious,which are Co and Zr as well as Mg.The differentiations at different sites over coastal dune surface of Cr,Pb,Ti,Nb,As,Mn,Zn and Ba,are moderate,but the differentiations of some geochemical elements are slight,such as Y,Ca Fe,Na,Al,Sr,P,K,Rb and Si.The change features of geochemical elements in the modern aeolian sands at different sites,such as windward slope base,windward slope,dune crest,leeward slope and leeward slope base,on the surface of coastal aeolian transverse ridge are different,which could be concluded into different change models.The features and models of differentiation of geochemical elements at different sites over the surface of coastal aeolian transverse ridge are mainly controlled by the depositional environment,chemical characteristics of geochemical elements as well as grain-size of aeolian sands and so on.For examples,the geochemical elements such as Y,Ca Fe,Na,Al,Sr,P,K,Rb and Si,their differentiation features are mailly affected by depositional environment,but the differentiation of some microelements,such as Cr and Co,is mailly controlled by grain size of sands and the wind force.Based on the conclusions above,because there are clear differentiations of some geochemical elements such as some microelements at different sites over the surface of coastal aeolian transverse ridge,it should be very modest to