Sulfur Partitioning between Solid and Liquid Iron at High Pressure

高压下硫在铁液中的分配的Fe-FeS系统，共晶熔融行为和优先S分配到液态铁，已被用来作为一个模型系统来解释地球的基本观测？的核心系统，包括液体外核和固体内核结构和大密度跳跃内核边界（ICB）。为了评估S在核心形成和核心演化过程中的作用，需要充分了解Fe-FeS系统中的相关系作为压力到核心压力的函数。 建议在多顶砧装置中确定Fe-FeS系统中高达30 GPa的熔化关系，并将测量扩展到至少140 GPa的高温金刚石顶砧室中，使用原位观察和非原位表征与FIB/SEM结合。将开发一个热力学模型来重现实验数据，并用于外推实验确定的Fe-FeS系统的ICB条件下的相关系。重点是通过创新的实验设计和开发具有高空间分辨率的定量分析来获得可靠的高质量数据。虽然设计用于Fe-FeS二元系统的拟议工作，但这里开发的技术将开辟一类新的实验，将来可以应用于其他系统（例如，研究其他轻元素，如Si和O，在地球中的作用？s core）。热力学模型将被用来评估在ICB的密度跳跃的贡献，通过计算固体和液体铁之间的S分配和它的密度变化的影响。计算出的熔融温度作为一个函数的S含量将作为一个参考点，为其他多组分地球？的核心模型。广泛的影响。该研究将为实验岩石学的研究开辟新的方向。它解决了岩石学、矿物物理学、地球化学和地球物理学的界面上的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提供给社区。PI将继续参与和培训研究生和博士后研究员，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、参加科学会议以及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领域是必要的。预期结果将在实验岩石学、地球化学、地球物理学、矿物物理学和地球动力学等领域产生广泛影响。

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.