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Updated: Aug 6, 2026
10:44
Clean Sampling and Analysis of River and Estuarine Waters for Trace Metal Studies
Published on: July 1, 2016
Hydrogeochemical and Structural Controls on Rare Earth Element Distribution in Spring Waters from the Chongqing,
Juan Guo1, Chenxi Wang1, Wanjun Jiang2,3
1Institute of Water Resources Utilization and Water Environment, School of Architecture and Engineering, Yan'an University, Yan'an, China.
Summary
Rare earth elements (REEs) trace groundwater flow and water-rock interactions in karst aquifers. Tectonic structures control REE mobilization and fractionation by influencing groundwater circulation and chemistry.
Area of Science:
- Geochemistry
- Hydrogeology
- Environmental Science
Background:
- Rare earth elements (REEs) are crucial indicators of groundwater dynamics and water-rock interactions in carbonate aquifer systems.
- Understanding REE behavior is essential for deciphering complex hydrogeological processes in karst environments.
Purpose of the Study:
- To investigate the hydrochemical parameters and REE compositions of spring waters in Chongqing's fold-controlled karst aquifer.
- To elucidate the controls on REE mobilization, fractionation, and redox behavior within this specific aquifer system.
- To clarify the indirect influence of tectonic structures on REE geochemistry in groundwater.
Main Methods:
- Analysis of hydrochemical parameters (pH, Eh) and major ion chemistry to determine hydrochemical facies.
- Measurement of total dissolved REE concentrations (ΣREE) and their spatial distribution.
- Examination of NASC-normalized REE patterns to understand fractionation and redox influences.
- Correlation analysis to link REE concentrations with hydrogeochemical variables and environmental conditions.
Main Results:
- Spring waters showed a range of pH (6.2-8.4) and redox conditions (-338 to 148 mV), with hydrochemical facies evolving from Ca-HCO3 to Na-Cl types.
- Total dissolved REE concentrations (ΣREE) varied spatially (0.025-1.732 μg/L), with higher values in structurally complex areas.
- NASC-normalized REE patterns indicated LREE depletion and MREE-HREE enrichment, typical for carbonate aquifers, with Eu anomalies suggesting reducing or thermal conditions.
Conclusions:
- Groundwater circulation depth and water-rock interaction significantly influence REE mobilization, controlled by temperature, redox, and bicarbonate availability.
- Tectonic structures indirectly regulate REE behavior by controlling groundwater circulation pathways and associated hydrochemical conditions.
- REEs serve as effective tracers for understanding groundwater processes in complex karst systems influenced by structural geology.
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