Mantle Heterogeneity Shapes Earth’s Magnetic Field

Researchers used supercomputer simulations to show that the mantle’s heterogeneous cold and ultrahot regions create asymmetries in liquid‑iron flow, shaping the irregular shape and long‑term stability of Earth’s magnetic field.

6 February 2026 by

TechStora Editorial Board

Introduction

Recent research reveals that variations in the Earth’s mantle—specifically cold and ultrahot zones—affect the flow of liquid iron in the outer core, producing the irregular magnetic field we observe today.

Mantle’s Cold and Ultrahot Zones

These contrasting temperature regions accelerate or slow the iron flow depending on location, creating an asymmetry that distorts the magnetic field away from a perfect bar‑magnet shape.

Simulation Approach

The team compared two scenarios using supercomputer‑driven geodynamo models:

Uniform mantle composition
Mantle with heterogeneous structures, including Large Low‑Shear‑Velocity Provinces (LLSVPs)

Both models were matched against real magnetic field data.

Key Findings

Only the heterogeneous‑mantle model reproduced the observed irregularities, tilts, and patterns.
Some magnetic field regions have remained stable for hundreds of millions of years, while others changed dramatically.
The long‑term average magnetic field is not a perfect bar magnet aligned with Earth’s rotation axis.

Implications

These results suggest that mantle dynamics play a crucial role in shaping Earth’s magnetic field, influencing both its short‑term variations and its deep‑time stability.

Source and Credits

The story originally appeared in WIRED en Español and was translated from Spanish.