In order to characterize the chemical composition and the age of the water circulating in the critical zone of the Strengbach catchment (Vosges mountains, France), water samples from springs, 10–15 m deep piezometers and 50–120 m deep boreholes were collected and analyzed in elementary concentrations, in Sr, Nd, and U isotopic ratios, and in chlorofluorocarbon (CFC) and sulfur hexafluoride (SF₆) concentrations. The results evidence a clear distinction between surface water (<≈10–15 m) and deeper water. The latter has much higher conductivity and cationic loads and is marked by lower Sr isotopic ratios and higher U activity ratios. Such a water typology suggests that the spring and piezometer water flows within the same shallow subsurface aquifer while deep borehole water belongs to a different circulation system, which flow path is controlled by the bedrock fracture network. The CFC data show that these two circulation systems are marked by contrasted residence times with a short residence time for the surface water and a longer residence time (water ages > 50 years) for the deep water. These results confirm different circulation histories for surface and deep water in the Strengbach catchment. They also suggest that the higher degree of chemical saturation of the deep water compared to the surface water is caused more by longer water residence times in the deep circulation systems than by differences in the primary minerals involved in each of the water-rock interaction systems. Our results also point that in the Strengbach granitic catchment, the SF₆ concentrations cannot be used for water dating due to their lithogenic production in granitic bedrocks.

为了表征 Strengbach 流域（法国孚日山脉）临界区循环水的化学成分和年龄，收集了泉水、10-15 m 深压力计和 50-120 m 深钻孔的水样，并在元素浓度、Sr、Nd 和 U 同位素比率以及氯氟烃 (CFC) 和六氟化硫 (SF ₆) 浓度。结果证明地表水 (<≈10–15 m) 和深层水之间存在明显区别。后者具有更高的电导率和阳离子负载，并以更低的 Sr 同位素比和更高的 U 活度比为特征。这样的水类型表明，泉水和测压计水在同一浅层地下含水层内流动，而深井水属于不同的循环系统，其流动路径受基岩裂缝网络控制。CFC 数据显示，这两种循环系统的特点是停留时间相反，地表水停留时间较短，深水停留时间较长（水龄 > 50 年）。这些结果证实了 Strengbach 流域地表水和深水的不同循环历史。他们还表明，与地表水相比，深水化学饱和度较高的原因更多是由于水在深层循环系统中的停留时间较长，而不是由于每个水岩相互作用系统中涉及的主要矿物的差异。我们的结果还指出，在 Strengbach 花岗岩集水区，SF₆浓度不能用于水测年，因为它们在花岗岩基岩中产生岩性。