The escape of heavy metals from the core of the Earth explained the seismic anomalies in Hawaii – in particular, why there is so much iron in their lava. A study by scientists from the University of California is published in the journal Nature Geoscience.
Modeling the structure of the Earth shows that the planet is a huge layered cake of various materials. The surface is a rocky crust, which is located above the hot mantle. Underneath is the outer core, an extremely hot ring of molten iron that surrounds the solid metal inner core.
In recent years, researchers have found evidence that the core constantly exchanges matter with the mantle through the so-called “D-layer” in the mantle. This is a two hundred kilometer layer of rocks that is directly in contact with the core of the planet.
In a new study, scientists added further evidence that the exchange process actually takes place. In laboratory conditions, they reproduced the conditions of the anomaly under which rocks that are not characteristic of it and occur only in the core appear in the mantle.
For this, scientists created a special installation that reproduces the conditions at the boundary of the mantle and the Earth’s core, placed cylinders of iron, nickel and a number of other elements in it, and then compressed them to ultrahigh pressures.
Experience has shown that elements behave differently – in particular, iron rises from the core to the mantle. This process, in particular, explains why there are so many heavy iron in the lava of some submarine Hawaiian volcanoes.
“If our calculations are correct, then the matter of the core constantly seeped into the upper layers of the lithosphere for many billions of years. A similar discovery explains why there is much more heavy iron in mantle rocks than in chondritic asteroids, which are made up of the primary matter of the solar system”.
Charles Loescher, lead author of the study.