Hydrothermal transport of Cu and Fe: internally-consistent thermodynamic model and application to formation of world-class iron-oxide-copper-gold (IOCG) ore deposits

铜和铁的热液传输：内部一致的热力学模型及其在世界级氧化铁铜金（IOCG）矿床形成中的应用

• 批准号: 367171245
• 负责人: Professor Dr. Thomas Wagner
• 金额: --
• 依托单位: Paul Scherrer Institut (PSI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/367171245?language=en
• 关键词: Hydrothermal; transport; Cu; Fe; internally

Hydrothermal ore deposits are large metal enrichments within the Earth´s crust. The formation of world-class ore deposits requires highly efficient extraction of metals from large volumes of source rocks, efficient transport by hydrothermal fluids and localized and effective metal precipitation. Fluid-rock interactions are essential processes during metal dissolution, transport and precipitation of ore minerals. Geochemical-thermodynamic modeling of fluid processes involved in ore deposit formation and hydrothermal alteration is a powerful tool for developing next-generation mineral exploration models. Robust thermodynamic datasets are an essential prerequisite to accurately simulate metal and mineral solubilities and fluid-rock reactions. This proposal seeks funding for developing a new internally-consistent geochemical-thermodynamic model for Cu and Fe transport in hydrothermal systems and applying this dataset to model the ore-forming processes that control mineralization and alteration in world-class iron-oxide-copper-gold (IOCG) and Copperbelt-type shale-hosted copper ore deposits. The proposed research builds on earlier work that addressed the key hydrothermal processes of the world-class Prominent Hill IOGC deposit in South Australia, based on ore geology, alteration lithogeochemistry, stable isotope and fluid inclusion studies. The project is organized as four work packages that will jointly contribute to fundamental understanding of how hydrothermal Cu ore deposits form in the Earth´s crust. In work package A, the new thermodynamic data regression module GEMSSPEC that can simultaneously treat experimental mineral solubility and optical spectroscopic data will be developed. Work package B will generate an internally consistent thermodynamic dataset for fluid-mineral equilibria in the system Na-K-Mg-Fe-Cu-Al-Si-C-S-Cl-O-H based on a new data regression approach recently developed at ETH Zürich. Carefully selected experimental Cu and Fe mineral solubility and spectroscopic data will be used for global fitting of the standard Gibbs energy of aqueous species to derive a consistent model for Cu and Fe transport in hydrothermal fluids. In work package C, the new thermodynamic dataset will be applied to the world-class Prominent Hill IOCG deposit for which datasets for rock composition, alteration mineralogy and the chemistry of ore fluids have been established. Geochemical-thermodynamic modeling using the GEMS3 code will result in a quantitative process model for the Prominent Hill deposit, which can be used to understand IOCG systems worldwide. In work package D, the new thermodynamic model will be used to address the first-order processes of Copperbelt-type shale-hosted Cu ore deposits.

热液矿床是地壳内的大型金属富集物。世界级矿床的形成需要从大量烃源岩中高效地提取金属，通过热液流体高效地输送金属，以及局部有效的金属沉淀。流体-岩石相互作用是矿石中金属溶蚀、运移和沉淀的重要过程。矿床形成和热液蚀变流体过程的地球化学-热力学建模是开发下一代矿产勘查模型的有力工具。强大的热力学数据集是准确模拟金属和矿物溶解度和流体-岩石反应的必要先决条件。该提案旨在为热液系统中Cu和Fe输运建立一个新的内部一致的地球化学-热力学模型，并将该数据集应用于世界级氧化铁-铜-金（IOCG）和copperbelt型页岩型铜矿床中控制矿化和蚀变的成矿过程建模。该研究计划建立在早期工作的基础上，基于矿石地质学、蚀变岩石地球化学、稳定同位素和流体包裹体研究，研究了南澳大利亚世界级Prominent Hill IOGC矿床的关键热液过程。该项目分为四个工作包，这些工作包将共同促进对地壳中热液铜矿如何形成的基本理解。在工作包A中，将开发能够同时处理实验矿物溶解度和光谱数据的新型热力学数据回归模块GEMSSPEC。工作包B将基于ETH z<e:1> rich最近开发的新数据回归方法，生成一个内部一致的系统Na-K-Mg-Fe-Cu-Al-Si-C-S-Cl-O-H的流体-矿物平衡热力学数据集。精心挑选的实验Cu和Fe矿物溶解度和光谱数据将用于水相的标准吉布斯能的全球拟合，以导出热液流体中Cu和Fe运输的一致模型。在工作包C中，新的热力学数据集将应用于世界级的Prominent Hill IOCG矿床，该矿床已经建立了岩石组成、蚀变矿物学和矿石流体化学数据集。使用GEMS3代码进行地球化学-热力学建模将为Prominent Hill矿床建立定量过程模型，可用于了解全球的IOCG系统。在工作包D中，新的热力学模型将用于解决铜带型页岩型铜矿床的一级过程。