Experimental earth and planetary materials sciences at extreme conditions of pressure and temperature

这项拟议的研究是一项多管齐下的实验调查，旨在了解地球、水星、火星和木星的卫星木卫一和木卫三的组成、状态和核心动力学。这些行星体的中心部分主要由铁及其硫和硅的稀合金组成。这些铁液合金的物理性质控制着基本的过程，如从核心到地幔的热流，以及核心内部磁场的产生和维持。我们方法的指导原则是，理解支配全球地球动力学的宏观尺度过程以我们对控制它们的行星材料的矿物物理和化学的微观方面的知识为基础。这项研究将包括在大容量压力下对液态铁-硫-硅合金和类似材料在极端压力(20 Gpa)和温度(2500K)下的电阻率、密度和粘度进行实验测量，以模拟这些行星体内深处的条件。将对U和Si同位素在液态金属和硅酸盐之间的分配进行进一步的研究。在计划期间，我们有一个由10名HQP组成的团队，我们将使用我们实验室开发的新技术，在下沉/浮法中使用复合球体来测量密度和粘度。同步辐射x射线照相术将提供球体在加压液体中运动的实时图像。这一结果预计将在地球深处和行星研究的三个领域具有重要意义。1.这些结果将有助于确定这些机构的核心成分。2.这些行星体核心的动力学(地球发电机和热流)的精确模型需要测量的物理性质。3.这些结果将直接解决沿压力相关熔融边界的恒定物理性质行为的基本物理问题。

The proposed research is a multi-pronged experimental investigation aimed at understanding the composition, state and core dynamics of Earth, Mercury, Mars and Jupiter's satellites Io and Ganymede. The central parts of these planetary bodies are composed primarily of iron and its dilute alloys of sulfur and silicon. The physical properties of these liquid iron alloys control fundamental processes such as heat flow from the core to the mantle as well as the generation and maintenance of magnetic fields inside their cores. The guiding principle of our approach is that understanding the macro-scale processes that govern global geodynamics pivots on our knowledge of the micro-scale aspects of the mineral physics and chemistry of planetary materials that control them. The research will involve experimental measurements of the electrical resistivity, density and viscosity of liquid iron-sulfur-silicon alloys and analog materials at extreme pressures (20GPa) and temperatures (2500K) in large volume presses to simulate the conditions deep inside these planetary bodies. Additional studies of partitioning of U and Si isotopes between liquid metal and silicate will be carried out. With a planned team of 10 HQP over the period of the proposal, we will employ novel techniques developed in our lab to measure density and viscoity using composite spheres in the sink/float method. Synchrotron x-ray radiography will provide real-time images of the sphere motion in the pressurized liquid. The significance of the results is expected in three areas of deep Earth and planetary studies. 1. The results will help to determine the core compositions of these bodies. 2. The measured physical properties are required for accurate models of the dynamics (geodynamo and heat flow) of the cores of these planetary bodies. 3. The results will directly address the basic physics of constant physical property behavior along the pressure-dependent melting boundary.