CAREER: Phase Diagrams and Elasticity of Iron Alloys in the Earth's Core

职业：地核铁合金的相图和弹性

• 批准号: 1056670
• 负责人: Jung-Fu Lin
• 金额: $ 48.62万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-15 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1056670&HistoricalAwards=false
• 关键词: CAREER; Phase; Diagrams; Elasticity; Iron

Because of its remoteness, together with extremely high pressures and temperatures, most direct observations of the Earth's core properties have come from teleseismic studies, requiring large earthquake sources and well-positioned seismometers to detect weak wave signals that have traversed through the Earth's deepest interior. In the last two decades, deep-Earth scientists have unveiled a number of unusual and enigmatic phenomena of the core, including inner core anisotropy, differential rotation of the inner core, fine-scale seismic heterogeneity, and the possible existence of the prefer-orientated iron alloys in the inner core. Understanding these phenomena will help test hypotheses on the Earth's formation, elucidate the geochemistry and the history of the Earth's deep interior, and determine the dynamic behavior of Earth's solid inner core and liquid outer core. This CAREER award investigates the alloying effects of major candidate light elements on the phase diagram and elasticity of iron under relevant pressures and temperatures of the core in order to address pressing issues on its composition, thermal structures, and seismic features. Working together with theorists and experimentalists, results from this award will ultimately be used to construct a forward model for the expected velocities, composition, and temperature profiles in the core. The thermoelastic modeling aspects of the proposal will provide students and postdoctoral researchers with a great opportunity to collaborate with scientists in the fields of seismology and geodynamics, helping them understand how laboratory mineral physics data are applied to deep-Earth issues and what kinds of new data are most urgently needed by the community.The proposed mineral physics research uses synchrotron X-ray spectroscopies in a laser-heated diamond anvil cell designed to probe structural and elastic properties of iron alloys at pressure-temperature conditions of the Earth's core. Under the initiatives of the projects, students and postdoctoral researchers will have unique research opportunities to use advanced synchrotron X-ray facilities at the Advanced Photon Source to obtain laboratory results needed to decipher seismic and geochemical observations of the planet's core. This will contribute to the education of the next generation of independent researchers with a thorough knowledge of the Earth's deep interior. Outreach activities in this CAREER award focus on exposing K-12th graders to deep-Earth research by involving in the outreach summer programs. A collection of displayable materials with information about deep-Earth research will be made available to students and teachers in the Austin School Districts to support the dissemination of accurate scientific knowledge and enthusiasm. Results from this award will be disseminated broadly through teaching, seminars, conferences, and peer-reviewed publications.

由于地处偏远，加上极高的压力和温度，对地球核心性质的最直接观测来自地震学研究，需要大型地震源和位置良好的地震仪来探测穿过地球最深内部的微弱波信号。在过去的20年里，深地科学家们揭示了许多不寻常的和神秘的现象，包括内核的各向异性，内核的差异旋转，精细尺度的地震不均匀性，以及内核中可能存在的优先取向的铁合金。了解这些现象将有助于测试地球形成的假设，阐明地球深部内部的地球化学和历史，并确定地球固体内核和液体外核的动力学行为。该职业奖调查了主要候选轻元素对相图的合金化效应以及在核心的相关压力和温度下铁的弹性，以解决其组成，热结构和地震特征的紧迫问题。通过与理论家和实验家的合作，该奖项的结果最终将用于构建核心预期速度，成分和温度分布的正演模型。该提案的热弹性建模方面将为学生和博士后研究人员提供一个与地震学和地球动力学领域的科学家合作的绝佳机会，帮助他们了解实验室矿物物理学数据如何应用于地球深部问题，以及社区最迫切需要什么样的新数据。拟议的矿物物理学研究使用激光同步加速器X射线光谱学-加热金刚石对顶砧，用于探测铁合金在地心压力-温度条件下的结构和弹性特性。在项目的倡议下，学生和博士后研究人员将有独特的研究机会，使用先进光子源的先进同步加速器X射线设施，获得破译地球核心地震和地球化学观测所需的实验室结果。这将有助于教育下一代对地球内部深处有透彻了解的独立研究人员。在这个职业奖的推广活动的重点是暴露K-12年级的深地球研究参与外展夏季计划。将向奥斯汀学区的学生和教师提供一套可展示的材料，其中载有关于深地研究的信息，以支持传播准确的科学知识和热情。该奖项的成果将通过教学、研讨会、会议和同行评审的出版物广泛传播。