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

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

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.