A new study conducted by geoscientists from Aarhus University and the University of California, Davis has found that the Earth’s molten core may be leaking heavy isotopes of iron.
Notably, the boundary between the liquid iron core and the rocky mantle is located around 2,900 km below the surface of earth and at this point the temperature falls by as much as thousand degrees from the hotter core to the cooler mantle.
According to the new study, heavier iron isotopes migrate toward lower temperatures while lighter iron isotopes circulate back down into the core and this is the reason why core material infiltrates the lowermost mantle to be enriched in heavy iron isotopes.
“If correct, this stands to improve our understanding of core-mantle interaction,” said Professor Charles Lesher from the University of California, Davis and Aarhus University.
“Understanding the physical processes operating at the core-mantle boundary is important for interpreting seismic images of the deep mantle, as well as modeling the extent of chemical and thermal transfer between the deep Earth and surface of our planet,” he added.
The researchers analyzed the movement of iron isotopes between areas of different temperatures. “Our findings can explain why there are more heavy iron isotopes in mantle rocks than in chondrite meteorites, the primordial material from the early Solar System,” Professor Lesher said.
“If true, the results suggest iron from the core has been leaking into the mantle for billions of years,” he added.
Professor Lesher and co-authors performed computer simulations to show that this core material can even reach the surface. The findings of the study were published in the journal Nature Geoscience.