TY - JOUR
T1 - Hydrogeochemical and isotope geochemical study of northwestern Algerian thermal waters
AU - Belhai, Mohamed
AU - Fujimitsu, Yasuhiro
AU - Bouchareb-Haouchine, Fatima Zohra
AU - Iwanaga, Tatsuto
AU - Noto, Masami
AU - Nishijima, Jun
PY - 2016/3/1
Y1 - 2016/3/1
N2 - Northwestern Algeria is characterized by a large number of thermal waters and volcanic eruptions and belongs to the Alpine-Magrebide belt. The geothermal reservoirs that feed these reservoirs are mainly hosted by a fractured Jurassic limestone and dolomite sequence. Seven samples were collected from thermal springs of near-neutral pH (6.2 to 7.56) with discharge temperatures between 42.9 and 66.1 °C. Hydrogeochemical analyses of the thermal waters reveal four types (Na+-Ca2+-Cl−, Na+-Ca2+-Cl−-HCO3 −, Na+-Ca2+-Cl−-SO4 2−, and Na+-HCO3 −-Cl−) and show high total dissolved solids up to 4002 mg/L. Stable isotopic results (δ18 O and δ D) indicate that the thermal waters are of meteoric origin deeply infiltrated and heated by advective heat anomalies and raised up to the surface through deep-seated faults acting as hydrothermal conduits. The estimated reservoir temperatures using silica geothermometers and fluid-mineral equilibria overlap between 66 and 125 °C, while Na/K and K/Mg geothermometers give much higher and lower results, respectively, and are mainly influenced by mixing with cooler Mg groundwaters as indicated by the Na-K-Mg plot in the immature water field and in silica and chloride mixing models. Thermal waters deeply circulated and heated at a depth of 2 km were supplied by the higher geothermal gradients, which can reach 42.8 °C km−1 due to the complex geological setting.
AB - Northwestern Algeria is characterized by a large number of thermal waters and volcanic eruptions and belongs to the Alpine-Magrebide belt. The geothermal reservoirs that feed these reservoirs are mainly hosted by a fractured Jurassic limestone and dolomite sequence. Seven samples were collected from thermal springs of near-neutral pH (6.2 to 7.56) with discharge temperatures between 42.9 and 66.1 °C. Hydrogeochemical analyses of the thermal waters reveal four types (Na+-Ca2+-Cl−, Na+-Ca2+-Cl−-HCO3 −, Na+-Ca2+-Cl−-SO4 2−, and Na+-HCO3 −-Cl−) and show high total dissolved solids up to 4002 mg/L. Stable isotopic results (δ18 O and δ D) indicate that the thermal waters are of meteoric origin deeply infiltrated and heated by advective heat anomalies and raised up to the surface through deep-seated faults acting as hydrothermal conduits. The estimated reservoir temperatures using silica geothermometers and fluid-mineral equilibria overlap between 66 and 125 °C, while Na/K and K/Mg geothermometers give much higher and lower results, respectively, and are mainly influenced by mixing with cooler Mg groundwaters as indicated by the Na-K-Mg plot in the immature water field and in silica and chloride mixing models. Thermal waters deeply circulated and heated at a depth of 2 km were supplied by the higher geothermal gradients, which can reach 42.8 °C km−1 due to the complex geological setting.
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U2 - 10.1007/s12517-015-2252-2
DO - 10.1007/s12517-015-2252-2
M3 - Article
AN - SCOPUS:84959373932
VL - 9
SP - 1
EP - 17
JO - Arabian Journal of Geosciences
JF - Arabian Journal of Geosciences
SN - 1866-7511
IS - 3
M1 - 169
ER -