Hydrothermal properties of complex aqueous solutions, and applications to ore-forming systems

复杂水溶液的水热性质及其在成矿系统中的应用

• 批准号: RGPIN-2018-04370
• 负责人: SteeleMacInnis, Matthew
• 金额: $ 3.5万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=750912
• 关键词: Hydrothermal; properties; complex; aqueous; solutions

Geologic fluids control numerous processes within the Earth driving chemical reactions, transporting heat and material, and promoting melting and magmatism. Modern analytical methods reveal that these fluids are commonly complex brines with high concentrations of diverse solutes. In ore-forming settings in particular, complex brines dissolve and transport elements to form mineral deposits. However, geochemical processes involving complex, saline fluids are mostly interpreted qualitatively owing to the lack of quantitative models for the properties of such fluids. Thus, there is a critical need to develop models to predict and model quantitatively the physical and chemical properties of complex brines.The objective of this work is firstly to develop new thermodynamic models to characterize the compositions and mineral solubilities of complex, geologic brines based on data obtained from fluid inclusions in minerals tiny droplets of fluids trapped within minerals as they grow and secondly to apply these methods to analyze fluids from two major ore-forming settings. This work will involve new thermodynamic models for brines which will be built into computer programs. This work will also involve field- and laboratory-based studies of fluids degassed from magmas in the deep roots of porphyry systems, and of saline brines derived from seawater evaporation in the context of base-metal deposits.This work will provide researchers with the tools to explore the compositions of geologic fluids in diverse settings, and to relate fluid composition to hydrothermal alteration and mineral precipitation. The field-based portions of the study will address two major questions: How fluids evolve during the waning stages of magma crystallization, and how variations of seawater composition through time affect compositions and ore-forming potentials of evaporite-derived brines.The work described here is novel because at present, fluid properties are still mostly interpreted using approximations based on H2O-NaCl. This work will represent a major step forward in allowing robust characterization of fluids. Computer programs implementing these models will facilitate applications of these new methods to illuminating the properties of real fluids in many settings. The applications of these new approaches to characterizing magmatic and basinal fluids will provide new insights into the physical and chemical processes at work in these settings. These outcomes will be beneficial to Canada because hydrothermal fluids are crucial to the formation of economic mineral deposits. This research will provide new insights into the nature of these fluids and how they react with rocks to form mineral deposits. Thus, broadly, this research will improve our understanding of the fundamental controls on ore formation.

地质流体控制着地球内的许多过程，驱动化学反应，运输热量和物质，并促进熔融和岩浆。现代分析方法表明，这些流体通常是复杂的盐水，具有高浓度的溶质。特别是在矿石形成的环境中，复杂的盐水会溶解和运输元素形成矿藏。但是，由于缺乏这种流体特性的定量模型，涉及复合物的地球化学过程大多被定性地解释。因此，迫切需要开发模型来定量预测和建模复合盐的物理和化学特性。这项工作的目的首先是开发新的热力学模型，以根据基于复杂的，地质盐水的组成和矿物质溶解度来表征基于复杂的矿物质和矿物质溶解度从矿物质中的流体夹杂物中获得的数据，随着矿物质的生长而被困在矿物质中的微小液滴，其次是应用这些方法来分析来自两个主要的矿石形成设置的流体。这项工作将涉及用于盐水的新型热力学模型，这些模型将内置在计算机程序中。这项工作还将涉及斑岩系统深根中从岩浆中脱胶的液体和基于实验室的研究，以及在碱基沉积的背景下从海水蒸发中衍生出的盐水盐水。这项工作将为研究人员提供工具探索在不同环境中地质流体的组成，并将流体组成与热液改变和矿物沉淀相关。该研究的基于田间的部分将解决两个主要问题：流体如何在岩浆结晶的衰落阶段演变，以及如何通过时间来影响蒸发液的盐水的成分和形成矿石的潜力。之所以新颖，是因为目前，流体特性仍然主要使用基于H2O-NaCl的近似值来解释。这项工作将代表允许液体表征的重大一步。实施这些模型的计算机程序将促进这些新方法的应用，以阐明许多设置中真实流体的属性。这些新方法在表征岩浆和盆地液中的应用将为这些环境中工作中的物理和化学过程提供新的见解。这些结果将对加拿大有益，因为水热液对形成经济矿藏至关重要。这项研究将为这些液体的性质以及它们如何与岩石做出形成矿物质沉积物的反应提供新的见解。因此，从广义上讲，这项研究将提高我们对矿石形成的基本控制的理解。