University of Liverpool: £3.3M to investigate Earth’s mantle convection

The University of Liverpool has been awarded a £3.3 million NERC Large Grant to study the structure of the Earth’s mantle, the solid yet hot and mobile part of the Earth which drives evolution of the crust.

The mantle lies between the Earth’s very hot core and the crust, the thin outermost layer. Mantle convection is the very slow creeping motion of Earth’s solid silicate mantle, with convection currents carrying heat from the interior to near the planet’s surface.

To understand mantle convection, it is necessary to understand mantle density which is determined in turn by the minerals forming the mantle rocks.

In the standard picture of the mantle, different minerals are stable at different pressures, and pressure is controlled by depth. Seismic waves confirm this, showing that the mantle is composed of layers of different densities: layer boundaries are controlled by depth, with a subsidiary influence of temperature. The variations in density create buoyancy contrasts which drive mantle movement – it is essential for our understanding of Earth evolution to understand such density variations. However, there are many anomalies in the seismic data that require further explanation.