The Geochemical Features and Evolution of Laterite in the Karst Areas of Guizhou Province

(整期优先)网络出版时间:1996-04-14
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Guizhouisoneofthedominatingkarstregions,wherelateriteiswidespread,inChina.Seventy-twolateritesamplesweretakenfromtwelvelateritesectionsinthekarstareasofGuizhouProvince,whicharepossessedoftypicalsubtropicalkarstgeomphologicalandecologicalenvironmentalfeaturesandhaveevolvedcompletelyfromdolostonesandlimestones.Intermsofthemajor,traceandREEdetaforthdsamplesthispaperdiscussesthegeochemicalcharacteristicsoflateriteinthekarstareaswithanattempttodisclosethegeochemicalprocessandevolutionaryruleoflateriteformation.Therehavebeeninvolvedthreeimportantpedogeneticgeochemicalprecessesintheformationoflateriteinthekarstareas:(1)enrichmentofsiliconandaluminumanddepletionofcalciumandmagnesium;(2)enrichmentofironandmanganese;and(3)enrichmentofaluminumanddepletionofsilicon.Duringtheformationandevolutionoflaterite,obviousenrichmentanddifferentiationoftraceelementssuchasCu,Pb,Zn,Ni,Co,Cr,Pb,F,Cl,andAscanbeobserved,butfortherare-earthelements,theirenrichmentisremarkableagainstaweakdifferentiation.TheREEdistributionpatternsinthelateritearesimilartothoseofitsparentalcarbonaterocks.