Application of Principal Components Analysis to the study of CO₂-rich thermomineral waters in the aquifer system of Alto Guadalentín (Spain)

Abstract

The southeast of the Betic Cordilleras has long been recognized as an area with numerous geothermal anomalies of regional character. Many thermal springs appear related to currently tectonically active fault systems. Carbon dioxide and other gases in these waters have been mobilized through those fault systems. The great depth of these "slip-strike zones" affects the entire thickness of the lithosphère and leads to contrasting crustal domains of different natures and structures. In this area, the detrital aquifer of the Alto Guadalentin has thermal waters with high salinity and unusually high contents of C0 2 gas. The utilization of Principal Components Analysis (PCA) in the hydrogeochemical study of this aquifer has revealed that the origin of the salinity of its waters is due essentially to processes of dissolution of the Miocene evaporite rocks, principally sulphate, and to the contribution of deep hydrothermal waters that show signs of endogenous C0 2 contamination. To a lesser extent, infiltration waters also form an input, with elevated sulphate, chloride and nitrate content. Likewise, PCA has enabled the differentiation of distinct groups of water to which these processes have had a variable contribution.

Groundwater intensive use and mining in south-eastern peninsular Spain: Hydrogeological, economic and social aspects

“…So groundwater mining is accompanied in some areas, although not always, by progressive water quality impairment, mostly an increase in sulfate content Pulido-Bosch el al., 1995). In the Guadalentín river valley, near Lorca, some deep wells produced CO 2 rich water after completion (Cerón et al, 1999;Solís el al., 1994), probably of geogenic origin and related to deep faulting.…”

La explotación intensa de los acuíferos en la cuenca baja del Segura y en la cuenca del Vinalopó

“…El Alto Guadalentín comenzó antes a ser explotado con intensidad y a ser utilizado para riego en la comarca de Mazarrón. Los niveles empezaron a bajar entre 1 y 3 m al año y pronto en algunos sondeos aparecieron problemas de gases, especialmente CO 2 que dieron problemas en los equipos de bombeo y en las conducciones con obstrucciones, roturas y problemas de corrosión que añadido al problema de los descensos de nivel y el empeoramiento de la calidad química del agua obligaron al abandono de muchos pozos (Cerón et al, 1999). La explotación en 1973 fue de 24 hm 3 /año y 69 hm 3 /año en 1987 con bajadas de nivel de 2.5 m/año en el periodo (1973)(1974)(1975)(1976), 4.5 m/año en el (1976-1984) y 9 a 10 m/año en el (1984)(1985)(1986)(1987).…”

Acquisition de salinité et qualité des eaux d’une nappe profonde en Tunisie: approche statistique et géochimique

“…L'analyse des données géochimiques en vue de déterminer les processus et les sources de la minéralisation des eaux souterraines de la nappe de la Jeffara est basée en partie sur les techniques statistiques (Melloul et Collin 1992, Morell et al 1996, Cerón et al 1999, Güler et al 2002, Hamzaoui et al 2011.…”