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的变化而不断变化。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的质量，使其流向含盐端元。很少有研究侧重于通过考虑平衡常数、地下水流动状态和反应动力学（即反应路径模型）来确定盐化反应的连续阶段，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，研究水岩相互作用。在未来5年，我们将为未来的项目奠定基础，以实现这一长期目标。我们计划聘请2名博士（PhD1和PhD2）和1名硕士（MSc1）学生进行未来5年的项目。我的短期研究目标是：1)探索裂缝和水/岩相互作用在地下水盐化过程中的作用以及地下水中微量和超微量元素的富集和/或枯竭；2)确定盐碱化过程端元的化学基准：(a)结晶基底深水，(b)古生代石灰岩水，(c)水-粘土相互作用水，(d)更新世冰川融水，(e)雨水；3)研究端元混合过程。为了实现第一个目标，博士一将专注于实验室实验和反应输运建模。博士一将首先实施一个实验系统，研究裂缝和流体地球化学蚀变的主要过程。利用观测、实验、建模和理论方法，博士将提供高质量的力学和化学耦合过程数据，用于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，博士2将使用单变量和多变量统计分析技术调查数据集合。博士2将确定基线化学特征，这可能成为任何在前寒武纪地盾背景下讨论水的起源和混合物的新研究的基础。为了实现第三个目标，MSc1将利用Niobec矿井的设施，更深入地了解盐水和最近的陨石水之间的联系（混合/稀释过程）及其对地下水质量的影响。这三个研究项目是相互关联的，因此在第一年结束时，至少有两名学生将以跨学科的方式合作。对于UQAC来说，在已经建立的含水层水力学专业知识中心的基础上，发展一个定量水文地球化学专业知识中心，将鼓励许多卓有成效的国家和国际合作，并有助于在水资源管理方面以科学为基础的改进。

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.