Geochemical characteristics of major, trace and rare earth elements in typical carbonate weathered profiles of GuizhouPlateau
Guizhou Plateau is located in the east of Yunnan-Guizhou Plateau, where variable karst landscapes are widely distributed. The major, trace and rare earth elements of a typicalin-situ weathering profile of carbonate rock on karst terrain of Guizhou Plateau have been researched to provide evidence of elements’ geochemical behaviours in the weathering crust. The results indicate thatthesamples are characterized by enrichment in Pb and Co and depletion in Sr, Na, Ba, K, Rb and Cr in the profile according toupper continental crust (UCC)normalized spiderdiagram of samples. The total amount of REEsranges between167.4~1814.2μg/g. REEsdecrease gradually fromlowerto upper regolith of the profile and LREEs show more leaching than HREEs in the middle and upper part of the profile. The element Ce has been separated from the other REEs, chondrite-normalized REEs distribution patterns show significant Ce-anomalies and slight negative Eu-anonalies. Ce shows negative anomalies in the lower partof theregolithin weathering front,but positive anomaliesin the upper part. In addition, the concentration of elements in rock-soil interface grows by an average of 21 timesmorethan that in the rock powder, whichshows a clear mutation of alkaline barrier near the rock-soil interface. Our research shows that the variations of major and trace elements are well correlated in the weathering profile, indicatingthatthey have the same geochemical behaviors during the weathering process.Ferruginous nodular horizon contains the lowest REEs,which issimilarin the case of upper continental crust (UCC),and we believe that this can be referred toin researching the relation between UCC and ferruginous nodular horizon of carbonate rocks.
major elementstrace elementsREEcarbonate rockrock powderferruginousnodular horizonweathering frontier
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万方数据
维普
