Groundwater flow and residence time in a karst aquifer using ion and isotope characterization
Author
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DÍaz Puga, M.
Author
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Vallejos, A.
Author
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Sola, F.
Author
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Daniele, Linda
Author
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Molina, L.
Author
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Pulido Bosch, A.
Admission date
dc.date.accessioned
2017-10-31T13:58:04Z
Available date
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2017-10-31T13:58:04Z
Publication date
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2016-11
Cita de ítem
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Int. J. Environ. Sci. Technol. (2016) 13:2579–2596
es_ES
Identifier
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10.1007/s13762-016-1094-0
Identifier
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https://repositorio.uchile.cl/handle/2250/145411
Abstract
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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, C-14) 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 delta S-34 content.
es_ES
Patrocinador
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This work takes part of the general research lines promoted by the CEI-MAR Campus of International Excellence as a joint initiative between the universities of Almeria, Granada, Huelva and Malaga, headed by the University of Cadiz. This work was supported by the Andalusia Regional Government, Spain, through the Excellence Research Project P06-RNM-01696 and by MINECO-FEDER, through Project CGL2015-67273-R.