Groundwater flow and residence time in a karst aquifer using ion and isotope characterization
| Autor: | Ángela Vallejos, Antonio Pulido-Bosch, Linda Daniele, Luis Molina, Fernando Sola, M. A. Díaz-Puga |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Hydrology
geography Environmental Engineering geography.geographical_feature_category Groundwater flow 0208 environmental biotechnology Dolomite Geochemistry Aquifer 02 engineering and technology 010501 environmental sciences Karst 01 natural sciences 020801 environmental engineering chemistry.chemical_compound chemistry Environmental Chemistry Carbonate rock Carbonate Saltwater intrusion General Agricultural and Biological Sciences Geology Groundwater 0105 earth and related environmental sciences |
| Zdroj: | International Journal of Environmental Science and Technology Artículos CONICYT CONICYT Chile instacron:CONICYT |
| Popis: | In order to identify the origin of the main processes that affect the composition of groundwater in a karstic aquifer, a hydrogeochemical and isotopic study was carried out of water from numerous observation wells located in Sierra de Gador, a semiarid region in SE Spain. Several natural and anthropogenic tracers were used to calculate groundwater residence time within this complex aquifer system. Analysis of major ions enabled the principal geochemical processes occurring in the aquifer to be established, and the samples were classified into four distinctive solute groups according to this criterion. Dissolution of carbonate rocks determines the chemical composition of less mineralized water. In another group, the concurrent dissolution of dolomite and precipitation of calcite in gypsum-bearing carbonate aquifer, where the dissolution of relatively soluble gypsum controls the reaction, are the dominant processes. Marine intrusion results in highly mineralized waters and leads to base exchange reactions. The groundwater enrichment of minor and trace elements allowed classification of the samples into two classes that are linked to different flow patterns. One of these classes is influenced by a slow and/or deep regional flow, where the temperature is generally elevated. The influence of sulphate reduces by up to 40 % the barium concentration due to the barite precipitation. Isotope data (T, 14C) confirm the existence of recent local flows, and regional flow system, and ages of ground water may reach 8000 years. The importance of gypsum dissolution in this aquifer is proved by the δ34S content. |
| Databáze: | OpenAIRE |
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