An unusual case of low concentration mineral brines in the geothermal waters from Beiuș Basin (Northwestern Romania)

Abstract

The aim of the BrineRIS project is to explore brines in RIS countries potential for critical metal extraction In the frame of this project the concentration of mineral brines in three geothermal wells located in the Beiuș Basin (northwestern Romania) was determined by analyzing the water from the wells. Until recently no reliable trace element data were available from Beiuș basin. Following the new analyses, the geothermal water extracted by TRANSGEX SA company from wells F-3001H, F-3003H, and F-3005H revealed exceptionally low concentrations of associated chemical compounds. The Li-concentration is only ~ 22 – 32 µg/l. Zn, I, Rb and As present in similar concentrations, while other trace elements (e.g. Co, V, Ti) are below detection limit. The Sr (~ 540 – 680 µg/l), Ba (~ 170 – 200 µg/l) and B (~ 70 – 100 µg/l) concentrations are slightly elevated, but still low. Therefore, the water in this "geothermal reservoir" can be classified as relatively potable, but it is not appropriate for critical metal extraction. In this paper, some documented concentrations from previous years have been compared to recent concentrations. In addition, the relationship between geology and water chemistry is emphasized in order to determine the reason for the absence of solutes that were expected to be found in this water.