Development of a quantitative framework to better understand the natural salinization processes of continental groundwater.

地下水的化学成分随着时间和空间不断变化。风化、离子交换、盐溶解和/或海水混合等过程往往会改变地下水沿其流动路径向含盐端元的质量。很少有研究通过考虑平衡常数、地下水流态和反应动力学（即反应路径建模）来重点定义盐化反应的连续阶段，而很少关注大陆盐水的稀土元素 (REE) 特征。我的长期愿景是在 UQAC 建立一个实验实验室来研究水-岩石相互作用。未来5年，我们将为未来的项目奠定基础，以实现这一长期目标。我们拟聘请2名博士（PhD1和PhD2）和1名硕士。 （MSc1）学生开展未来5年的项目。我研究的短期目标是： 1）探索裂缝和水/岩石相互作用对地下水盐化过程以及地下水微量和超微量元素富集和/或耗竭的作用； 2) 确定盐化过程终端成员的一套化学基准：(a) 结晶基底的深水，(b) 古生代石灰岩水，(c) 源自水-粘土相互作用过程的水，(d) 更新世冰川融水，以及 (e) 雨水； 3）研究端元混合过程。为了实现第一个目标，PhD1 将专注于实验室实验和反应传输建模。 Ph.D1将首先实施一个实验系统来研究裂缝和流体地球化学蚀变的主要过程。通过使用观测、实验、建模和理论方法，PhD1 将提供有关耦合机械和化学过程的高质量数据，以解释和预测流体化学的时间演化以及裂缝演化。为了实现第二个目标，PhD2 将使用单变量和多元统计分析技术调查数据集。 Ph.D2 将确定基线化学特征，这可能构成前寒武纪地盾背景下任何新研究的基础，以讨论水的起源和混合物。为了实现第三个目标，MSc1 将利用 Niobec 矿山设施，更深入地了解盐水和近期陨石水（混合/稀释过程）之间的联系及其对地下水质量的影响。这 3 个研究项目是相互关联的，因此到第一年结束时，至少有两名学生将采用跨学科方法进行合作。对于 UQAC 来说，建立一个定量水文地球化学专业知识中心，作为对含水层水力学方面已经完善的专业知识中心的补充，将鼓励许多卓有成效的国内和国际合作，并有助于水资源管理方面基于科学的改进的发展。

The chemical content of groundwater is continuously modified through time and space. Weathering, ion exchange, salt dissolution and/or seawater mixing are among the processes that tend to modify groundwater quality along its flow path, toward a saline endmember. Few studies have focused on defining the successive stages of salinization reactions by considering equilibrium constants, groundwater flow regimes and reaction kinetics (i.e., reaction path modelling), with little attention paid to the rare earth element (REE) signature of continental brines. My long-term vision is to establish an experimental laboratory at UQAC to study water-rock interactions. Over the next 5 years, we will lay the foundation for future projects to achieve this long-term goal. We intend to hire 2 PhD (PhD1 and PhD2) and 1 M.Sc. (MSc1) students to carry out the coming 5-year project. The short-term objectives of my research are: 1) To explore the role of fractures and water/rock interaction on groundwater salinization processes and groundwater enrichment and/or depletion in trace and ultra-trace elements; 2) To determine a set of benchmarks for the chemistry of endmembers of salinization processes: (a) deep waters of the crystalline basement, (b) Paleozoic limestone waters, (c) waters originating from water-clay interaction processes, (d) Pleistocene glacial meltwater, and (e) rainwater; 3) To investigate endmember mixing processes. To achieve the first objective, PhD1 will focus on lab experiments and reactive transport modeling. PhD1 will first implement an experimental system to study the main processes involved in the geochemical alteration of fractures and fluids. Using observational, experimental, modelling and theoretical approaches, PhD1 will provide high-quality data on coupled mechanical and chemical processes for the interpretation and prediction of temporal evolution of fluids chemistry, as well as fracture evolution. To achieve the second objective, PhD2 will investigate a collection of data using univariate and multivariate statistical analysis techniques. PhD2 will determine baseline chemical signatures which may form the basis of any new studies in the context of the Precambrian Shield to discuss the origin and mixtures of water. To achieve the third objective, MSc1 will provide a deeper understanding of the connection between salt water and recent meteorite water (mixing/dilution processes) and its impact on groundwater quality, using Mine Niobec facilities. The 3 research projects are interrelated such that by the end of the first year, at least two students will be collaborating in an interdisciplinary approach. For UQAC, the development of a center of expertise in quantitative hydrogeochemistry in complement to the already well-established center of expertise in aquifer hydraulics will encourage many very fruitful national and international collaborations and contribute to the evolution of science-based improvements in water resource management.