Testing new models for sedimentary mineral behaviour

矿物是地球上金属、类金属和挥发性元素的最大源和汇。特别是沉积矿物在整个地球历史中在调节元素流动性和保存地球化学变化记录方面发挥了重要作用。沉积岩和变质沉积物也是铀、铅、贱金属（包括铁、锌和铜）、磷酸盐、稀土元素和贵金属（如金和银）的重要矿石所在。虽然沉积矿物的结构、性质和环境行为已经从经典的角度得到了很好的研究，但最近对矿物行为的深入了解使我们对它们作为污染物储存库的稳定性及其作为环境变化长期记录器的作用的许多基本假设产生了疑问。虽然沉积矿物行为的新模型继续在实验室中得到发展，但它们对地质过程的相对重要性尚未在实地得到系统的检验。需要根据新的见解重新评估沉积矿物的寿命和行为，这些见解揭示了它们储存的同位素和元素信息往往是短暂的。该提案的核心目标是测试（1）气体-矿物反应，（2）动态溶解-沉淀（即，（3）矿物置换作用，保存了碳酸盐、硫酸盐、硫化物、水滑石、卤化物和氢氧化物矿物中的元素、同位素和生物信息。将进行实验，以评估这些行为的重要性，在矿物学上类似的湖泊沉积物内的玄武岩Cariboo高原和巴斯克湖区中南部不列颠哥伦比亚省，加拿大。拟议研究的新奇在于，在实验室之外对非经典矿物行为进行研究，以量化其对复杂地球化学系统中真实的沉积物的影响。所有将被研究的矿物都是我们依赖于营养和污染物管理的矿物，我们用它们来重建地球上生命的历史。这项工作将使人们更好地了解如何调整矿物源和汇的行为，以及何时可以依靠沉积矿物作为古环境代理。

Minerals are the largest sources and sinks for metals, metalloids and volatile elements on Earth. Sedimentary minerals in particular have played an important role throughout Earth history in regulating element mobility and in preserving a record of biogeochemical change. Sedimentary rocks and metasediments also host important ores of uranium, lead, base metals (including iron, zinc and copper), phosphate, Rare Earth Elements, and precious metals (such as gold and silver). Although the structures, properties and environmental behaviours of sedimentary minerals have been well studied from a classical perspective, recent insights into the behaviour of minerals has thrown into question many of our fundamental assumptions about their stability as stores for contaminants and their role as long-term recorders of environmental change. While new models for sedimentary mineral behaviour continue to see development in the laboratory, their relative importance to geological processes has not been systematically tested in the field. A reassessment of the longevity and behaviour of sedimentary minerals is required in light of new insights that reveal the often transient nature of the isotopic and elemental information that they store. The core objectives of this proposal are to test the impacts of (1) gas-mineral reactions, (2) dynamic dissolution-precipitation (i.e., dynamic equilibrium), and (3) mineral replacement on preservation of the elemental, isotopic and biological information stored in carbonate, sulfate, sulfide, hydrotalcite, halide and hydroxide minerals. Experiments will be done to assess the importance of these behaviours within mineralogically similar lake sediments within the basaltic Cariboo Plateau and the Basque Lakes region in south-central British Columbia, Canada. The novelty of the proposed research lies in taking the study of non-classical mineral behaviour beyond the laboratory to quantify its impacts on real sediments in complex biogeochemical systems. All of the minerals that will be studied are ones that we rely upon for nutrient and contaminant management and that we use to reconstruct life's history on Earth. A greater understanding of how to tune the behaviour of mineral sources and sinks for the elements, and when sedimentary minerals can be relied upon as paleoenvironmental proxies, will result from this work.