High temperature, high pressure experiments involving a diamond anvil and chemicals to simulate the young Earth’s core demonstrate for the first time that hydrogen can bind strongly to iron under extreme conditions. This explains the presence of significant amounts of hydrogen in the Earth’s core which arrived as water as a result of bombardments billions of years ago.
Due to the extreme depths, temperatures and pressures involved, we are not physically able to directly probe very far into the earth. So, in order to peer deep inside the Earth, researchers use techniques involving seismic data to verify things like the composition and density of underground material. What has stood out since these types of measurements took place is that the core is mostly iron, but its density, especially that of the liquid part, is lower than expected.
This led researchers to believe that there must be an abundance of light elements alongside iron. For the first time, researchers examined the behavior of water in laboratory experiments involving metal iron and silicate compounds that accurately simulate metal-silicate (core-mantle) reactions during Earth formation. They found that when water meets iron, the majority of hydrogen dissolves in metal while oxygen reacts with iron and enters silicate materials.
“At the temperatures and pressures we’re used to on the surface, hydrogen doesn’t bind to iron, but we wondered if this was possible under more extreme conditions,” said PhD Shoh Tagawa. student at the Department of Earth and Planetary Sciences at the University of Tokyo during the study. “These extreme temperatures and pressures are not easy to reproduce, and the best way to achieve them in the lab was to use a diamond anvil. This can give pressures of 30 to 60 gigapascals at temperatures of 3100 to 4600 Kelvin. a good simulation of the formation of the Earth’s core. “
The team, led by Professor Kei Hirose, used metal and aqueous silicate analogous to those found in the Earth’s core and mantle, respectively, and compressed them into the diamond anvil while simultaneously heating the sample with a laser. To see what was going on in the sample, they used high-resolution imaging involving a technique called secondary ion mass spectroscopy. This allowed them to confirm their hypothesis that hydrogen binds to iron, which explains the apparent lack of water in the oceans. It is said that hydrogen likes iron or is siderophilic.
“This discovery allows us to explore something that affects us in quite a deep way,” Hirose said. “The fact that hydrogen is siderophilic under high pressure tells us that much of the water that came to Earth in massive bombardments during its formation could be found in the heart as hydrogen today.” hui. If this had remained on the surface as water, the Earth might never have known the earth, and life as we know it would never have evolved. “
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