CSEDI Collaborative Research: Towards a unified model of the geomagnetic, geochemical, and thermal evolutions of Earth's mantle and core

CSEDI 合作研究：建立地幔和地核地磁、地球化学和热演化的统一模型

• 批准号: 1361221
• 负责人: Joseph Stoner
• 金额: $ 15.4万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-01 至 2016-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1361221&HistoricalAwards=false
• 关键词: CSEDI; Collaborative; Research; Towards; unified

The magnetic field of the Earth, generated inside the fluid portion of Earth's Iron core, protects the Earth and orbiting satellites from a barrage of potentially harmful charged particles streaming through space. The magnetization of ancient rocks has shown us that the magnetic field has been shielding Earth for at least 3.5 billion years. Beyond that age, there are no observations currently available to assess if a magnetic field was present. It is a mystery when exactly the magnetic field arose, and also a challenging puzzle as to how it has been sustained for billions of years. The answers to those questions will greatly impact our understanding of how our Earth evolved from its initial state into a habitable planet able to develop and sustain life on its surface. The proposed research aims to take a new approach to answer these difficult questions by looking at the role a deep magma ocean overlying Earth's core might have played in helping sustain an ancient magnetic field. Recent experiments that are able to simulate the extreme pressures and temperatures within Earth's deep interior have provided new knowledge on how Earth materials behave under such conditions. Using this recently gained information on material properties, in conjunction with theoretical considerations of the energetics of magnetic field generation, this project will build physics-based models of Earth's interior and cooling through time. These efforts will specifically investigate scenarios in which there is a long-lived magma ocean on top of the core. These models will test if this scenario can explain the generation of Earth's magnetic field during ancient times. While we will learn directly about the Earth's deep interior, this work impacts our understanding of surface processes as well, since the magnetic shielding of highly charged particles aimed at Earth (or lack thereof) will affect the atmosphere and surface of the Earth.

地球的磁场是在地球铁芯的流体部分内产生的，可保护地球和绕线卫星免受潜在的有害带电颗粒的弹性，这些颗粒通过太空流过。古代岩石的磁化表明，磁场一直在屏蔽地球至少35亿年。超过该年龄，目前尚无观察结果可以评估是否存在磁场。当磁场出现时，这是一个谜，对于数十亿年的持久方式，这也是一个挑战性的难题。这些问题的答案将极大地影响我们对地球如何从最初状态演变为能够在其表面发展和维持生命的宜居行星的理解。拟议的研究旨在通过研究深层海洋核心的角色来帮助维持古老的磁场，以采用一种新的方法来回答这些困难的问题。能够模拟地球深内部内部的极端压力和温度的最新实验提供了有关地球材料在这种条件下的行为方式的新知识。使用最近获得有关材料特性的信息，结合了磁场产生能量学的理论考虑，该项目将建立基于物理的地球内部模型和随着时间的流逝而冷却。这些努力将专门研究核心之上寿命长的岩浆海洋的场景。这些模型将测试这种情况是否可以解释古代地球磁场的产生。虽然我们将直接了解地球深内部的内部，但这项工作也影响了我们对表面过程的理解，因为针对地球（或缺乏其缺乏）的高电荷颗粒的磁屏蔽将影响地球的大气和表面。