The density of H2O-NaCl-CO2/SiO2 fluids in the crust and upper mantle

地壳和上地幔中H2O-NaCl-CO2/SiO2流体的密度

• 批准号: 502766828
• 负责人: Professorin Dr. Carmen Sanchez-Valle, Ph.D.
• 金额: --
• 依托单位: Institut für Mineralogie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/502766828?language=en
• 关键词: density; H2O; NaCl; CO2; SiO2

Aqueous fluids are major vector for mass (and heat) transfer in the Earth’s interior and their reactive flow through the crust and mantle controls the mobilization and transport/deposition of elements and solute species. A quantitative understanding of fluid-mediated mass transport processes thus relies on an accurate modeling of fluid-rock interactions that couples the thermochemical description with the integrated fluid flow regimes. Modeling of reactive fluid flow in deep settings is however limited due to sparse constrains on the density of mixed saline-volatile solvents at relevant high pressure-high temperature conditions. The aim of this proposal is thus to develop experimentally constrained density models for mixed complex fluids in the H2O-NaCl-CO2/SiO2 system that is a proxy for deep fluids in a broad range of geological settings, from mid-oceanic ridges to subduction zones. We will apply a combination of synchrotron X-ray absorption and Brillouin scattering spectroscopy coupled with high pressure vessels outfitted for hydrothermal studies to extend the available density data over one order of magnitude in pressure, up to 60 kbar and 800 ⁰C. The gathered experimental datasets will be implemented in continuous predictive density models valid at conditions that pertain to fluid processes in the crust and upper mantle. The new density models will be formulated to ensure compatibility with numerical codes that simulate reactive fluid flow in crustal settings. Ultimately, this will permit the application of the present results to constrain the effect of fluid chemistry on the fluid pathways and time scales and hence, on the formation of large metal deposits.

含水流体是地球内部物质（和热量）传递的主要载体，它们通过地壳和地幔的反应流动控制着元素和溶质物种的流动和运输/沉积。因此，流体介导的质量输运过程的定量理解依赖于流体-岩石相互作用的准确建模，该建模将热化学描述与集成流体流动状态耦合起来。然而，由于在相关的高压-高温条件下混合盐-挥发性溶剂的密度的稀疏约束，在深层设置中的反应性流体流动的建模是有限的。因此，本提案的目的是为H2O-NaCl-CO2/SiO2系统中的混合复杂流体开发实验约束密度模型，该系统是从大洋中脊到俯冲带的广泛地质背景中深部流体的代理。我们将应用同步加速器X射线吸收和布里渊散射光谱的组合，再加上为热液研究配备的高压容器，以将可用的密度数据扩展到一个数量级的压力，高达60千巴和800摄氏度。收集的实验数据集将在地壳和上地幔流体过程条件下有效的连续预测密度模型中实施。将制定新的密度模型，以确保与模拟地壳环境中反应性流体流动的数字代码兼容。最终，这将允许应用本结果来约束流体化学对流体路径和时间尺度的影响，从而约束对大型金属矿床的形成的影响。