Rare Earth Elements and Yttrium Geochemistry of Eastern Black Sea Region (Ordu, Rize, Artvin) Geothermal Fields

Abstract

In this study, behavior and migration processes of rare earth elements (REEs) were determined in the thermal and cold waters of the geothermal fields in the Eastern Black Sea Region.The temperatures of the geothermal waters are between the range of 38 and 60 °C. The water types are Na-Ca-SO 4 for Sarmaşık (Ordu) field, Na-Ca-HCO 3 for Ikizdere (Rize) field, Na-Ca-CO 3-SO 4 , for Ayder (Rize) field and Na-HCO 3-Cl for Savsat (Artvin) field. All geothermal fields are in alkaline geothermal character (pH: 7-9.3) and have very low REE + Y concentrations, slightly significant Ce contens and significantly positive Eu anomalies (except for Ayder geothermal field). REE+Y content, fractionation and positive Eu anomalies of the investigated water are controlled by water/rock ratio, pH and minerals in the host rocks. According to the thermodynamic calculations, it was determined that the mobility of the REEs in geothermal fields were mainly controlled by Ln 3+ , LnOH 2+ , LnCl 2+ , Ln(SO 4) 2-, LnSO 4 + , LnHCO 3 2+ , Ln(CO 3) 2 and LnCO 3 + complexes.

Current status and potentials of enhanced geothermal system in the Eastern Pontide Orogenic Belt, Turkey

“…Turkey benefits from medium and high temperature geothermal fields due to its location within an active tectonic zone and a young volcanic belt. Among these locations, the EPOB stands out as one of the regions with medium enthalpy geothermal resources (Karakaya et al, 2007;Bayramoğlu, 2018;Gültekin et al, 2019;Hatipoğlu Temizel et al, 2019;Yücel, 2019;Hatipoğlu Temizel et al, 2020;Vural and Gündoğdu, 2020;Karayel et al, 2022;Şener et al, 2023) and EGS potential (Şener et al, 2022; Figure 1).…”

“…In addition, geothermal water temperatures in the geothermal areas of the EPOB generally vary between 38 and 60°C. The water types generally consist of Na-Ca-SO4, Na-Ca-HCO3, and Na-Ca-HCO3-SO4, and the pH values vary between 7 and 9.3(Hatipoğlu Temizel et al, 2019).…”