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

由于地处偏远，再加上极高的压力和温度，对地核性质的最直接观察都来自远震研究，这需要大型震源和位置良好的地震仪来探测穿过地球最深处的微弱波信号。在过去的二十年里，地球深部科学家已经揭示了一些不寻常和神秘的地核现象，包括内核各向异性，内核的微分旋转，精细尺度的地震非均质性，以及内核中可能存在的择优取向铁合金。了解这些现象将有助于测试关于地球形成的假设，阐明地球地球化学和地球深层内部的历史，并确定地球固体内核和液体外核的动态行为。该奖项研究了主要候选轻元素在核心相关压力和温度下对铁的相图和弹性的合金效应，以解决其组成、热结构和地震特征等紧迫问题。与理论学家和实验学家一起工作，该奖项的结果最终将用于构建核心中预期速度，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，帮助他们了解如何将实验室矿物物理数据应用于地球深部问题，以及社区最迫切需要哪种新数据。提出的矿物物理研究在激光加热的金刚石砧细胞中使用同步加速器x射线光谱，旨在探测地核压力-温度条件下铁合金的结构和弹性特性。在这些项目的倡议下，学生和博士后研究人员将有独特的研究机会，利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。这将有助于培养对地球深层内部有全面了解的下一代独立研究人员。这个职业奖的拓展活动重点是通过参与拓展暑期项目，让k -12年级的学生接触到地球深处的研究。将向奥斯汀学区的学生和教师提供一系列有关地球深部研究信息的可展示材料，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、会议和同行评议的出版物广泛传播。

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.