The geochemical characteristics of aqueous rare-earth elements in shallow karst groundwater in Guiyang City, China  

作　　者：HE Shouyang ZHU Lijun YANG Ruidong SHEN Zheng YU Xiaohong 

机构地区：[1]Key Laboratory of Karst Environment and Geological Hazard Prevention （Guizhou University）, Ministry of Education, Guiyang 550003, China [2]College of Resource and Environment, Guizhou University, Guiyang 550003, China [3]Postgraduate School of Guizhou University, Guiyang 550025, China [4]Guizhou Institute of Geo-Environment Monitoring, Guiyang 550004, China

出　　处：《Chinese Journal Of Geochemistry》2011年第1期114-124,共11页中国地球化学学报

基　　金：supported by the National Basic Research Program (973) of China (No. 2006CB403202) ;the National Natural Science Foundation of China (No. 40463001)

摘　　要：Fifty-seven shallow groundwater samples were collected from Guiyang karst basin, China, to analyze the aqueous rare-earth elements in low-water seasons and it is shown that the total amount of rare-earth elements (ΣREE) in karst groundwater is exceedingly low compared with that in carbonate rocks or weathering crusts of carbonate rocks, and ranges from 0.01 to 0.43, from 0.03 to 0.27, from 0.03 to 0.19 and from 0.05 to 1.38 μg·L-1 for dolomite, dolomitic & limestone, limestone and clastic rock aquifer, respectively. Both distributions and contents of rare-earth elements (REE) in karst groundwater reflect the lithology of host rocks or weathering crusts of carbonate rocks through which groundwater flows. The chondrite-normalized patterns show a non-flat profile with higher enrichment of slightly light rare-earth elements (LREE) than heavy rare-earth elements (HREE), prominent fractionation between LREE and HREE, negative Ce anomalies and negative or positive Eu anomalies. There is more obvious fractionation between LREE and HREE in groundwater than that in carbonate rocks and their weathering crusts due to high contents of HCO3? and PH in groundwater. In shallow karst groundwater, REE(CO3)n2n-3 (n=1 and 2) is the main inorganic species of REE. But for a clastic rock aquifer, both REESO4+ and REECO3+ are the main inorganic species of REE. Species of REE in groundwater is closely associated with the hydrochemical type of groundwater which is predominated by the lithology of host rocks, groundwater-rock interaction and weathering-pedogenesis of carbonate rocks.Fifty-seven shallow groundwater samples were collected from Guiyang karst basin, China, to analyze the aqueous rare-earth elements in low-water seasons and it is shown that the total amount of rare-earth elements （ZREE） in karst groundwater is exceedingly low compared with that in carbonate rocks or weathering crusts of carbonate rocks, and ranges from 0.01 to 0.43, from 0.03 to 0.27, from 0.03 to 0.19 and from 0.05 to 1.38 μg.L-1 for dolomite, dolomitic ＆ limestone, limestone and clastic rock aquifer, respectively. Both distributions and contents of rare-earth elements （REE） in karst groundwater reflect the lithology of host rocks or weathering crusts of carbonate rocks through which groundwater flows. The chondrite-normalized patterns show a non-flat profile with higher enrichment of slightly light rare-earth elements （LREE） than heavy rare-earth elements （HREE）, prominent fractionation between LREE and HREE, negative Ce anomalies and negative or positive Eu anomalies. There is more obvious fractionation between LREE and HREE in groundwater than that in carbonate rocks and their weathering crusts due to high contents of HCO3- and PH in groundwater. In shallow karst groundwater, REE（CO3）n^2n-3 （n=l and 2） is the main inorganic species of REE. But for a clastic rock aquifer, both REESO4＋ and REECO3＋ are the main inorganic species of REE. Species of REE in groundwater is closely associated with the hydrochemical type of groundwater which is predominated by the lithology of host rocks, groundwater-rock interaction and weathering-pedogenesis of carbonate rocks.

关 键 词：重稀土元素 岩溶地下水 地球化学特征 贵阳市 碳酸盐岩风化壳 中国 轻稀土元素 浅水 

分 类 号：P641.134[天文地球—地质矿产勘探] O614.33[天文地球—地质学]