The temperature 3,000 kilometres below the surface of the Earth is much more varied than previously thought, scientists have found.
The discovery of the regional variations in the lower mantle where it meets the core, which are up to three times greater than expected, will help scientists explain the structure of the Earth and how it formed.
"Where the mantle meets the core is a more dramatic boundary than the surface of the Earth," said the lead researcher, Associate Professor Hrvoje Tkalči?, from The Australian National University (ANU).