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Glauberite (Na2Ca[SO4]2) is an evaporitic mineral which is used in the industries of detergents, paper, glass, pharmacy, etc. Glauberite rocks are seldom found cropping out because they are very sensitive to weathering processes; for this reason their prospection is conducted by means of boreholes. Nowadays, geophysical techniques are not used to support the characterization of glauberite deposits due to the lack of knowledge of their physical properties. In this study geoelectrical methods are proposed as alternative techniques in the early stages of glauberite prospecting. Several glauberite units have been studied in different parts of the Ebro basin (Spain) by means of electrical resistivity tomography sections. The electrical resistivity range showed by glauberite deposits has been found to be low (10–100 O·m) when the matrix component (clay and microcrystalline carbonates) is above 45% of the bulk composition of the rock. This type of rocks has been studied in Montes de Torrero (Zaragoza) and is the most common glauberite deposit case. Besides matrix-rich glauberite rocks, an exceptional case of a pure glauberite layer has been studied in Alcanadre (La Rioja). From this site, it has been estimated that deposits with glauberite crystal fraction close to 100% show a resistivity range of at least 3 × 103 O·m. Using this extreme value as reference, the Hashin–Shtrikman bounds have been calculated for glauberite rocks considering that they are constituted of four phases (glauberite, gypsum, anhydrite and matrix). When the matrix fraction represents 45% or more of the bulk rock, the resistivity range will be that of the lower Hashin–Shtrikman bound, which is similar for any combination of sulfate (glauberite, gypsum and/or anhydrite) composition; hence, it can be considered as a two-phase system (matrix and sulfate). For rocks with less than 30% of matrix fraction, the upper Hashin–Shtrikman bound trend must be considered; however, the resistivity values overlap, ma, Postprint (published version)

La glauberita es un sulfato sódico que se explota con fines industriales. En el año 2002 en los depósitos evaporíticos miocenos de la formación Yesos y Anhidritas de Zaragoza se encontró glauberita en profundidad en una campaña de sondeos. Mediante la técnica geofísica de la tomografía eléctrica se han llevado a cabo una serie de perfiles de resistividad eléctrica del terreno. Los datos obtenidos en el estudio se han comparado con la información previa de los sondeos y se ha podido constatar que partiendo de estos, es posible obtener información de los depósitos y observar como evolucionan lateralmente. Debido a la importante presencia de encajante no se ha podido definir el rango de valores geoeléctricos de resistividad propios de la glauberita pura pero si se han reconocido estructuras kársticas y deposicionales., Postprint (published version)