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部的许多过程，驱动化学反应、传输热量和物质、促进熔化和岩浆作用。现代分析方法表明，这些流体通常是含有高浓度不同溶质的复杂盐水。特别是在成矿环境中，复杂的盐水溶解并输送元素以形成矿床。然而，由于缺乏针对此类流体性质的定量模型，涉及复杂含盐流体的地球化学过程大多是定性解释的。因此，迫切需要开发模型来定量预测和模拟复杂卤水的物理和化学性质。这项工作的目的首先是开发新的热力学模型，根据从矿物中的流体包裹体（在矿物生长过程中捕获的微小流体液滴）获得的数据来表征复杂地质卤水的成分和矿物溶解度，其次应用这些方法来分析来自两个主要矿物的流体。 成矿环境。这项工作将涉及新的盐水热力学模型，这些模型将被内置到计算机程序中。这项工作还将涉及对斑岩系统深层岩浆脱气流体的现场和实验室研究，以及贱金属矿床背景下海水蒸发产生的盐水的研究。这项工作将为研究人员提供工具来探索不同环境中的地质流体成分，并将流体成分与热液蚀变和矿物沉淀联系起来。该研究的现场部分将解决两个主要问题：在岩浆结晶的衰弱阶段流体如何演化，以及海水成分随时间的变化如何影响蒸发岩衍生卤水的成分和成矿潜力。这里描述的工作是新颖的，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。这项工作将代表着在流体的稳健表征方面向前迈出的重要一步。实现这些模型的计算机程序将有助于这些新方法的应用，以阐明许多环境中真实流体的特性。应用这些新方法来表征岩浆和盆地流体将为了解这些环境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利，因为热液对于经济矿藏的形成至关重要。这项研究将为这些流体的性质以及它们如何与岩石反应形成矿床提供新的见解。因此，从广义上讲，这项研究将提高我们对成矿基本控制的理解。