A new spin on Earth's deep mantle

Abstract

Earth's mantle is the largest distinct layer within the Earth, between the crust and the core. It accounts for roughly 2/3 of Earth's mass and is composed mainly of dense iron-bearing silicates. Laboratory experiments have recently shown that iron in mantle minerals undergoes a high-spin to low-spin transition driven by pressure, occurring at mid to lowermost mantle depths. This introduces a paradigm shift in our understanding of the physics and chemistry of the deep Earth.