This study focuses on the geochemical features of the presently discharging thermal and cold springs and on paleofluids from the upstream portion of the Reno river basin (Alto Reno; central–northern Italy). The aim is investigating the primary sources of the modern and fossil fluids and the interactions between deep and shallow aquifers. Paleofluids are from fluid inclusions hosted within euhedral and hopper quartz crystals and consist of a two-phase, liquid–vapor aqueous fluid and a unary CH₄ fluid. The aqueous inclusions have constant phase ratios and a calculated salinity of ~ 1.5 wt% NaCleq. They homogenize by bubble disappearance at 100–200 °C, whereas the estimated entrapment depth is ~ 3–5.5 km. The paleofluids likely represent the vestiges of the deep and hot, CH₄-rich, Na⁺–Cl⁻ fluids produced by the interaction between meteoric waters and Triassic and Miocene formations. The modern Na⁺–Cl⁻(HCO₃⁻) thermal waters originate from meteoric waters infiltrating SW of the study area, at elevation > 800 m a.s.l., circulating within both the Triassic evaporites and the overlying Miocene turbiditic formations, where salt dissolution/precipitation, sulfate reduction, and production of thermogenic CH₄ occur. The equilibrium temperature of the deep fluid source is ~ 170 °C, corresponding to > 5 km depth. Cold springs are Ca²⁺–HCO₃⁻ type and show low amounts of biogenic CO₂ and CH₄ with no inputs of deep-originated fluids excepting in the immediate surroundings of the thermal area, confirming the lack of significant hydraulic connection between shallow and deep aquifers. We propose a genetic link between the quartz-hosted paleofluid and the thermal waters present in the area.

本研究的重点是目前排放的热泉和冷泉的地球化学特征以及雷诺河流域上游部分（上雷诺；意大利中北部）的古流体。目的是研究现代和化石流体的主要来源以及深水层和浅层含水层之间的相互作用。古流体来自自面体和漏斗石英晶体内的流体包裹体，由两相液-气水性流体和一元 CH ₄流体组成。含水包裹体具有恒定的相比和约 1.5 wt% NaCleq 的计算盐度。它们在 100-200°C 时通过气泡消失而均匀化，而估计的截留深度约为 3-5.5 公里。古流体可能代表了深而热、富含 CH ₄的 Na⁺ -Cl ^-大气水与三叠纪和中新世地层相互作用产生的流体。现代 Na ⁺ -Cl ^- (HCO ₃ ^- ) 热水起源于渗入研究区 SW 的大气水，海拔 > 800 m asl，在三叠纪蒸发岩和上覆的中新世浊积岩中循环，盐溶/沉淀、硫酸盐还原和产热 CH ₄的产生。深部流体源的平衡温度约为 170 °C，对应 > 5 km 深度。冷泉为 Ca ²⁺ –HCO ₃ ^-型，生物源 CO _2含量低和 CH ₄没有深源流体的输入，除了在热区的直接周围，证实了浅层和深层含水层之间缺乏显着的水力连接。我们提出了以石英为主体的古流体与该地区存在的热水之间的遗传联系。