Internally-consistent thermodynamic model for hydrothermal transport of Pb-Zn-Ag-Au-As-Sb: development and application to formation of sediment-hosted Pb-Zn and epithermal Ag-Au-As-Sb deposits

热液矿床是地壳中的大型金属富集物，世界级矿床的形成需要从大量源岩中高效提取金属，热液流体的有效迁移以及局部有效的金属沉淀。流体-矿物相互作用是形成岩浆-热液斑岩型Cu-Au-Mo矿床、浅成低温热液型Ag-Au-As-Sb矿床和沉积岩型Pb-Zn矿床等世界级矿床的重要过程。矿床存款形成和热液蚀变的地球化学-热力学模拟是开发下一代成矿系统模型的有力途径。强大的热力学数据集是准确模拟金属和矿物溶解度以及流体-矿物反应的必要前提。该提案旨在为Pb-Zn-Ag-Au-As-Sb的热液传输开发一个新的内部一致的地球化学-热力学模型提供资金，从而显着扩展我们现有的数据集。该数据集将被应用于数值模拟一级地球化学过程，控制沉积物为主体的喷流和碳酸盐为主体的铅锌矿床和浅成热液银金砷锑矿床的形成。该模型将解决与这些全球重要的矿床存款类型的形成，即还原酸和氧化卤水在沉积物中的相对作用，喷流和碳酸盐岩托管的铅锌矿床之间的联系，以及对铜，铅，锌，银和Au的热液运输的非金属As和Sb的影响有关的关键问题。该项目由三个工作包组成，共同从根本上了解热液沉积物中的铅锌矿床和岩浆热液银金砷锑矿床是如何在地壳中形成的。在工作包A中，基于我们最近开发的新数据回归方法，将开发一个新的Pb-Zn-Ag-Au-As-Sb热液输运的内部一致的热力学模型。严格评估的实验溶解度和光谱数据Pb-Zn-Ag-Au-As-Sb将用于全球拟合的标准吉布斯能的水溶液物种，以获得一个一致的热液金属运输的热力学模型。在工作包B和C中，使用GEMS 3软件的地球化学建模将处理控制沉积物型铅锌矿床和与侵入有关的浅成热液型银金砷锑矿床形成的一级过程。该项目将通过与解决超热系统形成的对应项目合作，通过产生可供其他DOME参与者使用的热力学数据集，以及通过生成可由其他DOME项目的实地研究测试的建模预测，为DOME优先计划的超越目标做出重要贡献。

Hydrothermal ore deposits are large metal enrichments in the Earthʼs crust and the formation of world-class 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-mineral interactions are essential processes that lead to formation of world-class ore deposits such as magmatic-hydrothermal porphyry Cu-Au Mo and epithermal Ag-Au-As-Sb deposits, and sediment-hosted Pb-Zn deposits. Geochemical-thermodynamic modeling of the fluid processes driving ore deposit formation and hydrothermal alteration is a powerful approach for developing next generation ore systems models. Robust thermodynamic datasets are an essential prerequisite to accurately simulate metal and mineral solubilities and fluid-mineral reactions. This proposal seeks funding for developing a new internally-consistent geochemical-thermodynamic model for hydrothermal transport of Pb-Zn-Ag-Au-As-Sb, thereby significantly extending our existing dataset. The dataset will be applied to numerically simulate the first-order geochemical processes that control formation of sediment-hosted exhalative and carbonate hosted Pb-Zn deposits and of epithermal Ag Au-As-Sb deposits. The modeling will address key questions related to formation of these globally important ore deposit types, namely the relative role of reduced acid and oxidized brines in sediment-hosted Pb-Zn systems, the link between exhalative and carbonate hosted Pb-Zn deposits, and the effect of the metalloids As and Sb on the hydrothermal transport of Cu, Pb, Zn, Ag and Au. The project is organized as three work packages that will jointly lead to fundamental understanding of how hydrothermal sediment-hosted Pb Zn and magmatic-hydrothermal Ag-Au-As-Sb deposits form in the Earthʼs crust. In work package A, a new internally-consistent thermodynamic model for hydrothermal transport of Pb-Zn-Ag-Au-As-Sb will be developed, based on our new data regression approach that was recently developed. Critically evaluated experimental solubility and spectroscopic data for Pb-Zn-Ag-Au-As-Sb will be used for global fitting of the standard Gibbs energies of aqueous species to derive a consistent thermodynamic model for hydrothermal metal transport. In work packages B and C, geochemical modeling using the GEMS3 software will address the first-order processes that control formation of sediment-hosted Pb-Zn deposits and intrusion-related epithermal Ag-Au-As-Sb deposits. This project will make important contributions to the overaching goals of the DOME priority program, by collaboration with a counterpart project addressing the formation of epithermal systems, by producing a thermodynamic dataset ready for use by other DOME participants, and by generating modeling predictions that can be tested by field-based studies of other DOME projects.