New Finding: Light element layer in Earth's outer core

billiards

Researchers have found seismic evidence for a 300 km thick layer in the outer core formed of light elements expelled upon inner core solidification. They believe the gravitational energy released by this compositional convection is a key input to the energy that drives the geodynamo (responsible for the magnetic field we observe at the surface). Furthermore, this layer pools at the top of the outer core implying that any heat transferred in the upper 300 km must be done so without convection -- no convection in the upper 300 km of the outer core!

Pretty cool finding, which has major implication for geodynamic models.

http://www.nature.com/news/2010/1012....2010.657.html
http://www.bris.ac.uk/news/2010/7366.html