A team of Scientists will be going back in time to ascertain the processes that shaped Earth’s chemical composition in the first 600 million years of Earth's history, to an epoch called the Hadean aeon.
The Hadean aeon began with the formation of the Earth. It's thought Scientists named the epoch after the Greek god Hades who ruled the underworld because during most of the Hadean period the surface of Earth resembled what Christians imagine Hell to look like.
Scientists from around the globe have teamed up in the project called "Monitoring Earth Evolution through Time" (MEET).
Alexander Sobolev from the University Grenoble-Alpes in France, Stephan Sobolev from the German Research Center for Geosciences (GFZ) in Germany and John Valley from the University of Wisconsin in Madison USA, will make the tumultuous journey back more than 4.4 billion years to the first 600 million years of Earth’s history, when its molten surface was bombarded with chunks of planetary debris.
They secured a European Research Council Synergy grant of about $14.2 million over the next six years to support their research.
The MEET project will investigate two main questions: How has Earth's chemical composition evolved over time and what physical processes are responsible for these changes?
The project will use data from melt inclusions trapped in crystals and geodynamic modeling to reconstruct how Earth evolved from its early days.
Professor Alexander Sobolev said the most sensitive tracers of evolution - volatiles and mobile elements - are not accessible in old rocks.
“That's because these elements, like carbon, don’t stay put in the minerals," Prof Sobolev said.
The researchers will look specifically at the compositions of melt inclusions from the crust and the mantle. These tiny droplets are just 15 microns across – much smaller than the thickness of a piece of hair on your head.
However these melt inclusions do contain small amounts of water and other compounds allowing the scientists to evaluate what was happening on the Earth’s surface environment millions of years ago.
The researchers will analyze the composition of the melt inclusions, measure their isotopic signatures, and see how they have changed over time. Then, they will put all the data together, and with the help of specialised equipment develop a geophysical framework that explains how geological processes have altered Earth’s composition.
Besides offering insights into how the global carbon and water cycles evolved, MEET will address the question of when plate tectonics began.
Prof Sobolev said some people think that it started very early, from the beginning of the Hadean.
"Some think it started only one billion years ago. Many people think it started somewhere around 3 billion years,but nobody knows for sure.”
The MEET project builds on two recent pilot studies.
One used similar approaches to those proposed in MEET to find evidence that subduction or an earlier system for recycling ocean crust was already in place by 3.3 billion years ago, while the second found that surface processes, like erosion, helped kickstart plate tectonics.