标题： 使用81Kr和惰性气体在百万年时间尺度上表征和测定波罗的海自流盆地地下水和盐水的年龄 显示英文标题

标题： Using 81Kr and Noble Gases to Characterize and Date Groundwater and Brines in the Baltic Artesian Basin on the One-Million-Year Timescale

摘要： 对波罗的海含水层盆地（BAB）最深含水系统的地下水中的$^{81}$氪和稀有气体进行了分析，以确定地下水年龄并揭示该系统在几十万年时间尺度上的流动动力学特征。 我们发现该系统受三种不同的水体混合控制：间冰期或近期的降水水$(\delta^{18}\text{O} \approx -10.4\unicode{x2030})$，其化学和稀有气体特征未充分演化，冰川融水$(\delta^{18}\text{O} \leq -18\unicode{x2030})$，其稀有气体浓度较高，以及一种古老的高盐度卤水组分$(\delta^{18}\text{O} \geq -4.5\unicode{x2030}, \geq 90 \text{g Cl}^{-}/\text{L})$，其大气稀有气体浓度显著降低。 在这一混合框架内解释$^{81}$氪测量结果，以估算端元物质的年龄。 解混后的$^{81}$氪年龄范围为30万年到130万年，适用于间冰期或近期的降水水和冰川融水。 对于卤水组分，年龄超过 ATTA 3 仪器的测定范围130万年。 放射性成因的稀有气体组分$^{4}$He* 和$^{40}$Ar* 虽然结论不够明确，但也支持卤水年龄大于1 Ma。 根据化学成分和稀有气体浓度以及测年结果，我们得出结论，卤水来源于蒸发海水，后来经历了水-岩相互作用的改造。 由于获得的示踪剂年龄涵盖了多个冰期循环，我们讨论了冰期循环对所研究含水系统中流场的影响。 显示英文摘要

摘要： Analyses for $^{81}$Kr and noble gases on groundwater from the deepest aquifer system of the Baltic Artesian Basin (BAB) were performed to determine groundwater ages and uncover the flow dynamics of the system on a timescale of several hundred thousand years. We find that the system is controlled by mixing of three distinct water masses: Interglacial or recent meteoric water $(\delta^{18}\text{O} \approx -10.4\unicode{x2030})$ with a poorly evolved chemical and noble gas signature, glacial meltwater $(\delta^{18}\text{O} \leq -18\unicode{x2030})$ with elevated noble gas concentrations, and an old, high-salinity brine component $(\delta^{18}\text{O} \geq -4.5\unicode{x2030}, \geq 90 \text{g Cl}^{-}/\text{L})$ with strongly depleted atmospheric noble gas concentrations. The $^{81}$Kr measurements are interpreted within this mixing framework to estimate the age of the end-members. Deconvoluted $^{81}$Kr ages range from 300 ka to 1.3 Ma for interglacial or recent meteoric water and glacial meltwater. For the brine component, ages exceed the dating range of the ATTA 3 instrument of 1.3 Ma. The radiogenic noble gas components $^{4}$He* and $^{40}$Ar* are less conclusive but also support an age of > 1 Ma for the brine. Based on the chemical and noble gas concentrations and the dating results, we conclude that the brine originates from evaporated seawater that has been modified by later water-rock interaction. As the obtained tracer ages cover several glacial cycles, we discuss the impact of the glacial cycles on flow patterns in the studied aquifer system.