CSEDI: Understanding the influence of mantle dynamics on the generation of Earth's magnetic field throughout the plate tectonics cycle.

Earth's magnetic field acts as a shield against cosmic radiation and magnetic storms, which can potentially damage technical infrastructure, harm life, and strip away Earth's atmosphere. Understanding the evolution of the magnetic field therefore has important implications for Earth's habitability today and throughout history. An outstanding question that currently limits understanding of the evolution the magnetic field is: When did the solid inner core form?

Today, the solidification of the inner core is an important driver of the geodynamo, which generates Earth’s magnetic field. This project seeks to better constrain the timing of inner core formation, which will be accomplished by a unique coupling of mantle convection models to geodynamo simulations that produce Earth-like magnetic fields. The results from this project will have a scientific impact in multiple disciplines, including geodynamics, magnetospheric physics, studies of the deep interior, and the evolution of life.

More generally, this project addresses the important question of “How is Earth’s internal field generated?”, which can help to better predict future magnetic field changes that could result in harm to modern technical infrastructure or life itself. Additionally, the proposed work will support two early-career female PIs, build STEM talent by training and educating two undergraduate students and one postdoctoral researcher, improve available scientific infrastructure by releasing the created software as open-source, and will facilitate international exchange with project collaborators in the UK and France.

A wide audience will be engaged through a multi-year outreach initiative building on the successful Scientist in Every Florida School program in collaboration with University of Florida Thompson Earth Systems Institute.

Because the growth of the inner core is a major driver of the geodynamo today, it can be assumed that inner core nucleation may have caused significant changes in Earth's past magnetic field. But so far, the interpretation of any detectable signal in the paleomagnetic data at the Earth’s surface has remained ambiguous because (1) the precise effects of inner core nucleation on the magnetic field are unknown, and (2) the magnitude of magnetic field variations caused by mantle convection are currently not well constrained.

This project will quantify the largest possible influence of mantle heat transport on the magnetic field at Earth’s surface, taking into account the influence of inner core size. This will be accomplished by computing realistic core-mantle boundary heat flux patterns generated by mantle convection models, and coupling them to geodynamo simulations that produce Earth-like magnetic fields as assessed with the Quality of Paleomagnetic Modeling (QPM) criteria, which is currently the only criteria set that assesses if simulations are reproducing Earth’s long-term magnetic field behavior.

In contrast to previous studies, these mantle models do not try to recreate the relatively limited timeframe of known plate motions, or apply simplified heat flux patterns for present-day conditions, but instead predict the largest realistic heat flux variations caused by synthetic plate configurations during the cycle of supercontinent formation and dispersal in Earth's past. This work will improve understanding of the mantle’s role in regulating the magnetic field throughout Earth's history.

Additionally, this work will determine whether changes in the magnetic field so far ascribed to inner core nucleation could instead partly or completely be explained by mantle dynamics alone. This project connects planetary evolution, mantle convection, the geodynamo, and paleomagnetic data. This wide collaboration will drive significant advances in the understanding of the Earth as one system, not separated into its layers.

More generally, this project addresses the science priority question, “How is Earth’s internal field generated?”, released in the National Academies of Science, Engineering and Medicine decadal report for NSF-EAR.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.