Understanding the Influence of the Mantle on Earth's Magnetic Field, Dan Thallner, MagIC, 28/2/23
Channel: Magnetics Information Consortium (MagIC)
Date: 11/03/2023

"Coupling Mantle Convection and Geodynamo Simulations to Understand the Influence of Mantle Dynamics on the Generation of Earth's Magnetic Field Throughout the Plate Tectonic Cycle" by Dan Thallner

Talk presented at the 2023 Magnetics Information Consortium (MagIC) Workshop: Magnetism and Earth History: Field Evolution, Environmental Change and Paleogeography, Feb 28th-Mar 2nd, 2023. Convened at the Scripps Institute of Oceanography, UCSD in La Jolla, California and sponsored by the National Science Foundation (NSF).

Workshop website: https://earthref.org/events/MAGIC/2023/

Abstract:

The current understanding of Earth’s interior’s long-term evolution relies strongly on our understanding of the behavior and variations of Earth’s geomagnetic field through geologic time. Variations in the magnetic field occur on a broad range of timescales. Most short-term variations are attributed to stochastic processes in the outer core, but long-term (more than 10 Myr) variations have been suggested to be related to large scale processes including planetary evolution (e.g., formation of the inner core) and changes in forcing arising from mantle convection. How these large-scale processes influence changes of the magnetic field and how they would be visible in the paleomagnetic record is still not fully understood. Even though the cooling history of the core is governed by the heat transport through the mantle, the influence of the mantle on the geodynamo is not yet fully explored. New simulations of 3D mantle convection using the geodynamic modeling software ASPECT, predict a range of plausible heat maps at the core-mantle boundary (CMB) using Earth-like materials and a plate reconstruction of the past billion years. We use these maps as boundary conditions for thermally driven numerical geodynamo simulations to systematically explore the impact of the most extreme variations of CMB heat flux patterns and amplitudes on the geodynamo and tie those variations to paleomagnetic observables.