Abstract Ophiolites often form complex, fractured, multi-lithological and highly compartmentalized aquifers that are difficult to characterize. Groundwater chemistry reflects water-rock interactions and can provide insights to groundwater recharge mechanisms, flow paths and relative residence time. A comprehensive hydrogeochemical modelling approach with PHREEQC has been developed to identify water-rock interactions and simulate groundwater evolution and mixing with connate water in fractured aquifers. The methodology was applied in the gabbro aquifers of Troodos Massif (Cyprus). The geochemical processes generating the most frequently observed water types were reproduced through modelling. Based on the overall results, a generic evolution path has been identified: CaMgHCO3 → MgCaHCO3 → CaMgNaHCO3 → Ca/Mg/Na/HCO3/SO4 → NaMgHCO3SO4 → NaSO4/Cl group. CaMgHCO3 and MgCaHCO3 types were modelled to occur predominantly in early stages of recharge. Deep unsaturated zones and longer flow paths result in gradual removal of Ca+2 and Mg+2 from groundwater, through secondary mineral precipitation, and in an increase of Na+2 and SO4−2. The most frequently occurring water types, CaMgNaHCO3 and MgCaNaHCO3, were modelled to occur at later stages of hydro-chemical evolution, after secondary mineral precipitation, and in closed conditions. In regional flow, where closed conditions with secondary mineral precipitation prevail, water types progressively shift from the HCO3 to the NaSO4 end-member group. In 38% of the 536 samples from gabbro aquifers in Troodos, groundwater mixing with connate water at a ratio of ≥0.999:0.001 occurs.

中文翻译：

---

特罗多斯断裂含水层辉长岩中地下水的水化学演化。综合方法

摘要 蛇绿岩通常形成复杂的、断裂的、多岩性和高度分隔的含水层，难以表征。地下水化学反映了水-岩相互作用，可以提供对地下水补给机制、流动路径和相对停留时间的见解。PHREEQC 开发了一种综合水文地球化学建模方法，用于识别水-岩相互作用并模拟地下水演化以及与裂缝含水层中原生水的混合。该方法应用于 Troodos Massif（塞浦路斯）的辉长岩含水层。通过建模再现了产生最常观察到的水类型的地球化学过程。根据总体结果，确定了一个通用的演化路径：CaMgHCO3 → MgCaHCO3 → CaMgNaHCO3 → Ca/Mg/Na/HCO3/SO4 → NaMgHCO3SO4 → NaSO4/Cl 组。CaMgHCO3 和 MgCaHCO3 类型被模拟主要发生在补给的早期阶段。较深的不饱和带和较长的流动路径导致从地下水中逐渐去除 Ca+2 和 Mg+2，通过次生矿物沉淀，以及 Na+2 和 SO4-2 的增加。最常见的水类型 CaMgNaHCO3 和 MgCaNaHCO3 被模拟为发生在水化学演化的后期、次生矿物沉淀之后和封闭条件下。在区域流中，在封闭条件下，二次矿物沉淀占主导地位，水类型逐渐从 HCO3 转变为 NaSO4 端元组。在来自特罗多斯辉长岩含水层的 536 个样本中，有 38% 的地下水与原生水以≥0.999:0.001 的比例混合。