Effect of Redox and pH on the Reaction Kinetics of Anhydrite in a Coupled Chemical System: An Experimental Study with Implications for Modeling Vent Fluid Evolution at EPR 9-10 N

耦合化学系统中氧化还原和 pH 对硬石膏反应动力学的影响：一项实验研究，对 EPR 9-10 N 下排气流体演化建模具有意义

• 批准号: 0813861
• 负责人: William Seyfried
• 金额: $ 29.93万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0813861&HistoricalAwards=false
• 关键词: Effect; Redox; pH; Reaction; Kinetics

ABSTRACTOCE-0813861Intellectual Merit: The objective of the proposed experimental study entails acquisition of kinetic and thermodynamic data to enhance the development and application of geochemical models needed to constrain the temporal and spatial evolution of the expanding database for hydrothermal vent fluids at EPR 9-10°N and at other R2K IS Sites. Existing vent fluid data suggest that anhydrite coexisting with plagioclase, magnetite and calcic-bearing aluminosilicates may provide redox buffering in response to the addition of seawater derived sulfate into portions of subseafloor reaction zones at mid-ocean ridges. The redox buffer capacity unique to this chemical system, however, is a function of reaction rates between anhydrite and dissolved H2 and ferrous iron, the principle reducing agents derived from hydrolysis of primary and secondary minerals in basalt. At present little is known about the kinetics and thermodyamics of this system. The research project will obtain the requisite kinetic/thermodynamic data, and will apply these to geochemical models that will be used to constrain the temporal/spatial evolution of hydrothermal vent fluids at the East Pacific Rise 9N Ridge2000 Integrated Study Site, with applicability to the other Ridge2000 ISS as well. The project will make use of a newly-developed hydrothermal flow reactor with monitored pH and redox conditions. Broader Impacts: The project will provide essential data required for Ridge2000 integration and synthesis efforts, including the baseline data required for subsequent development of reaction-transport models. The acquisition of kinetic and thermodynamic data under hydrothermal conditions will help to develop reaction-transport models designed to couple physical and chemical processes in subseafloor reaction zones at mid-ocean ridges. This takes on added significance considering the potential role of anhydrite on crustal permeability at mid-ocean ridges. The proposed research will benefit from the participation of undergraduate summer interns in connection with the NSF/REU program in the Department of Geology and Geophysics at the UM entitled ?Fluids in the Earth?, while also enhancing graduate student training and mentoring. Moreover, the further development of the Ti-flow reactor in the course of the proposed study enhances the research infrastructure available to scientists involved in research and training in geology, biology and chemistry, as well as in a broad range of engineering disciplines.

Abstractoce-0813861Intlectual功绩：拟议的实验研究的目的需要获取动力学和热力学数据，以增强所需的地球化学模型的开发和应用，以限制扩展数据库在EPR 9-10°N和其他r2k上的临时和空间演化，以限制扩展数据库的临时和空间演化。现有的排气流体数据表明，与斜长石，磁铁矿和含有钙的铝纤维硅酸盐共存的赤铁矿可以响应在中山山脊上加入海水衍生的硫酸盐的一部分，从而提供氧化还原缓冲。然而，该化学系统所独有的氧化还原缓冲液的容量是硬石石和溶解的H2和铁铁皮之间的反应速率，这是底层中原发性和二级矿物质水解衍生的原理。目前，关于该系统的动力学和热力学知之甚少。该研究项目将获得必要的动力学/热力学数据，并将其应用于地球化学模型，这些模型将用于约束东太平洋上升9N Ridge2000集成研究地点的热液通风烟的临时/空间演化，并适用于其他Ridge2000 IS。该项目将利用具有受监视的pH和氧化还原条件的新开发的热液流动反应器。更广泛的影响：该项目将为Ridge2000集成和综合工作提供基本数据，包括随后开发反应传输模型所需的基线数据。在氢气条件下的动力学数据和热力学数据的获取将有助于开发旨在在中山脊的下腹反应区中培养物理和化学过程的反应传输模型。考虑到赤铁矿在中山脊上的潜在作用中，这具有更大的意义。拟议的研究将受益于本科夏季旅馆的参与与NSF/REU计划在地球上的地质和地球物理学系有关的“地球上的流体”，同时还可以增强研究生培训和心理培训。此外，在拟议的研究过程中，Ti-Flow反应堆的进一步发展增强了参与地质，生物学和化学研究和培训的科学家以及广泛的工程学科的研究基础设施。