Sulfur Partitioning between Solid and Liquid Iron at High Pressure

高压下固态铁和液态铁之间的硫分配

• 批准号: 1144422
• 负责人: Yingwei Fei
• 金额: $ 37.99万
• 依托单位: Carnegie Institution of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-01 至 2015-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1144422&HistoricalAwards=false
• 关键词: Sulfur; Partitioning; between; Solid; Liquid

Sulfur Partitioning between Solid and Liquid Iron at High PressureIntellectual Merit. The Fe-FeS system, with eutectic melting behavior and preferential S partitioning to liquid iron, has been used as a model system to explain the basic observations of the Earth?s core system, including the liquid outer core and solid inner core configuration and the large density jump at the inner core boundary (ICB). In order to evaluate the role of S during the core formation and evolution of the core, full knowledge of the phase relations in the Fe-FeS system as a function of pressure up to core pressures is needed. It is proposed to determine the melting relations in the Fe-FeS system up to 30 GPa in the multi-anvil apparatus and to extend the measurements up to at least 140 GPa in high-temperature diamond-anvil cell using combination of in-situ observations and ex-situ characterization with FIB/SEM crossbeam. A thermodynamic model will be developed to reproduce the experimental data, and used to extrapolate the experimentally determined phase relations in the Fe-FeS system to ICB conditions. Emphasis is placed on obtaining reliable, high-quality data through innovative experimental design and development of quantitative analysis with high spatial resolution. Although designed for proposed work on the Fe-FeS binary system, the techniques developed here will open a new class of experiments that can be applied to other systems in the future (e.g., to investigate the roles of other light elements, such as Si and O, in the Earth?s core). The thermodynamic model will be used to evaluate the S contribution to the density jump at the ICB by calculating the S partitioning between solid and liquid iron and its effect on the density change. The calculated melting temperature as a function of the S content will serve as a reference point for other multi-component Earth?s core models.Broad Impacts. The proposed research will open new research directions in experimental petrology. It addresses a broad issue in deep Earth study at the interface of petrology, mineral physics, geochemistry, and geophysics. The experimental techniques and procedures developed through this research will be available to the community. The PI will continue to involve and train graduate students and postdoctoral associates in the proposed research and provide them with broad, competitive research experience. Research results will be disseminated primarily through publications in scientific journals, participation at scientific conferences, and occasionally through public news media. The proposed projects will produce high-quality data that are necessary for understanding the interior of the Earth and developing new frontiers for cutting-edge research. The expected results will have broad impact in many different fields including experimental petrology, geochemistry, geophysics, mineral physics, and geodynamics.

高压下硫在固体和液态铁之间的分配理论价值。具有共晶熔化行为和S优先分配给液态铁的Fe-FeS系作为模型系统，解释了S地核系统的基本观测结果，包括液态外核和固体内核组态以及内核边界处的大密度跃迁。为了评价S在岩心形成和演化过程中的作用，需要充分了解Fe-FeS系统中的相关系作为压力到岩心压力的函数。提出了在多顶锤装置中测量高达30 Gpa的Fe-FeS体系的熔化关系，并利用FIB/SEM横梁结合原位观察和非原位表征相结合的方法，将高温金刚石顶压室中的熔化关系扩展到至少140 Gpa。将建立一个热力学模型来再现实验数据，并用于将实验确定的Fe-FeS体系的相关系外推到ICB条件下。重点是通过创新的实验设计和开发高空间分辨率的定量分析来获得可靠、高质量的数据。尽管是为Fe-FeS二元系的拟议工作而设计的，但这里开发的技术将开启一类新的实验，在未来可以应用于其他系统(例如，研究其他轻元素，如硅和氧，在地球-S核心中的作用)。利用热力学模型，通过计算S在固体和液态铁之间的分配及其对密度变化的影响，来评价S对ICB密度跃迁的贡献。计算的熔融温度与S含量的函数关系将作为其他多组分S地核模型的参考点。该研究将为实验岩石学开辟新的研究方向。它在岩石学、矿物物理学、地球化学和地球物理学的界面上解决了地球深部研究中的一个广泛问题。通过这项研究开发的实验技术和程序将向社区提供。PI将继续让研究生和博士后助理参与拟议的研究并对他们进行培训，并为他们提供广泛的、有竞争力的研究经验。研究成果将主要通过在科学期刊上发表文章，参加科学会议，偶尔通过公共新闻媒体传播。拟议的项目将产生高质量的数据，这些数据对于了解地球内部和开发尖端研究的新前沿是必要的。预期结果将在许多不同领域产生广泛影响，包括实验岩石学、地球化学、地球物理、矿物物理和地球动力学。