In this study, multi-isotopic (O, H, C, S, Sr, B, Li) compositions were used to perform geochemical characterization, determine the source and reservoir rocks, and explain the water-rock interaction mechanisms for geothermal fluids in the low-enthalpy Havza (Samsun) geothermal field (HGF) in Turkey. The geothermal water of Na-HCO₃ water type has a wellhead temperature of 53°C, pH of nearly 7.7 and an EC value of 1140 µS/cm. The geothermal springs of Ca-HCO₃ water type have an EC value of nearly 667 µS/cm and a temperature of nearly 26°C. The reservoir temperatures of the HGF geothermal system were calculated as 60–90°C and 108–160°C by silica and SO₄-H₂O oxygen isotope geothermometers, respectively. Stable isotope compositions (δ²H and δ¹⁸O) show that the geothermal well water is mixed with deeply circulated waters fed from higher elevations (∼ 830–1260 m), while the geothermal spring water is mixed with shallow cold water. The positive δ¹³C value (+3.01‰) indicates that the dissolved inorganic carbon (DIC) in the geothermal well water has no contribution from the atmospheric CO₂ but originates in the metamorphic CO₂ and marine limestones. However, the DIC in the geothermal springs is derived from C3 plants and silicate weathering. The values of ³⁴S_CDT show that the sulfate in the geothermal waters is due to the dissolution of sulfate minerals. The values of δ¹¹B (-1.12 to +9.37 ‰) in the geothermal well and spring waters reflect both leaching of surrounding rocks and mantle-derived B. The reservoir rock may be Late Cretaceous-Permian limestones and Jurassic sandstones considering ⁸⁷Sr/⁸⁶Sr ratios (0.707108–0.707688) and δ⁷Li values (-7.44 to +6.18 ‰), whereas it might be Jurassic sandstones based on δ¹¹B values. The strontium isotope composition of the geothermal spring water indicates the mixing of deep geothermal waters and cold groundwaters.

在这项研究中，多同位素（O、H、C、S、Sr、B、Li）成分被用于进行地球化学表征，确定源岩和储集岩，并解释地热流体的水-岩相互作用机制。土耳其的低焓 Havza (Samsun) 地热田 (HGF)。Na-HCO ₃水型地热水井口温度53℃，pH值接近7.7，EC值为1140 μS/cm。Ca-HCO ₃水型地热泉的EC值接近667 µS/cm，温度接近26°C。HGF地热系统的储层温度分别通过二氧化硅和SO ₄ -H ₂ O氧同位素地温计计算为60-90°C和108-160°C 。稳定同位素组成（δ² H 和 δ ¹⁸ O）表明地热井水与从较高海拔（~830-1260 m）供给的深循环水混合，而地热泉水与浅冷水混合。δ ¹³ C 正值（+3.01‰）表明地热井水中的溶解无机碳（DIC）没有来自大气CO _{2 的}贡献，而是来源于变质CO ₂和海相石灰岩。然而，地热泉中的 DIC 来自 C3 植物和硅酸盐风化。³⁴ S _CDT值表明地热水中的硫酸盐是由于硫酸盐矿物的溶解。δ ¹¹的值地热井和泉水中的 B (-1.12 to +9.37 ‰) 反映了围岩淋溶和幔源 B。考虑到⁸⁷ Sr/ ⁸⁶ Sr 比值 (0.707108) ，储层可能是晚白垩世-二叠纪灰岩和侏罗纪砂岩–0.707688) 和 δ ⁷ Li 值（-7.44 至 +6.18 ‰），而根据 δ ¹¹ B 值可能是侏罗纪砂岩。地热泉水中的锶同位素组成表明深部地热水和冷地下水混合。