若干典型岩性区域沉积物金属元素地球化学特征比较研究

研究了４种成片分布的典型岩性（页岩、石灰岩、花岗岩、黄土）区域沉积物金属元素（Ｌｉ、Ｎａ、Ｋ、Ｃａ、Ｓｒ、Ｂａ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ａｌ等共１６种）总量与形态特征．结果表明：这４种岩性区域沉积物金属元素含量与形态均有显著的差别．与其它岩性相比，黄土地区易迁移元素含量高，而重金属含量显著较低；其金属元素残渣态含量高，而有机态、铁锰氧化物态和可交换态含量低．石灰岩地区重金属含量较高，而易迁移元素如Ｎａ，Ｓｒ等含量则较低；其重金属元素残渣态含量不偏低，表明经风化作用释放出来的重金属参与了次生矿物的形成过程而得以富集．花岗岩地区重金属含量居中，而Ｆｅ和Ａｌ含量较高；其金属元素残渣态含量不偏高则与风化作用较强有关．页岩地区元素含量与形态均居中，代表了各种岩性的平均水平．

COMPARISON OF GEOCHEMISTRY OF METALS IN SEDIMENTS FROM SOME TYPICAL ROCK AREAS

Total contents and speciation of metals (Li,Na,K,Ca,Sr,Ba,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Al) in sediments from four typical rock areas of shales,limestone,granite,and loess were studied.Both the contents and speciation in sediments are different among the rock areas.Compared with the other rock areas,sediments in the loess area have high contents of mobile elements,but low contents of immobile elements.Metals in sediments of the loess area reside mainly in residual form,while the contents of organic,oxide,and exchangeable forms are relatively low.Contents of heavy metals in sediments from the limestone area are high,but those of immobile elements,such as Na and Sr,are low.The residual fractions of metals in sediments from the limestone area are not low,showing that the metals released by weathering have taken part in the formation of secondary minerals,and thus being enriched.Heavy metal contents in sediments from the granite area are moderate,but Fe and Al contents are rather high.Contents of the residual forms of metals in the granite area are not high,which is related with strong weathering forces.Contents and speciation of metals in sediments from shales area are moderate,showing average state of all rock areas.