It seems that our Earth’s core is changing, and a mysterious new layer appears. Here are all the details you have to know about this.
Earth’s core is changing
Water on Earth’s surface can travel deep into the planet and affect the outermost region of the metallic liquid core, according to new research.
This discovery could potentially solve a mystery that has puzzled geologists for decades – the presence of a thin layer of material inside the planet.
The Earth’s crust is made up of tectonic plates that move against each other. Over billions of years, these plates have transported water to the lower mantle through subduction zones.
When this water reaches the core-mantle boundary, which is located about 2,900 kilometers (1,800 miles) below the surface, it triggers a powerful chemical reaction.
A team of researchers from South Korea, the US, and Germany have found that this reaction creates a top core layer that is rich in hydrogen and sends silica to the lower mantle.
”For years, it has been believed that material exchange between Earth’s core and mantle is small,” says materials scientist Dan Shim from Arizona State University.
“Yet, our recent high-pressure experiments reveal a different story. We found that when water reaches the core-mantle boundary, it reacts with silicon in the core, forming silica.”
Earth’s magnetic field is generated by the combination of iron and nickel in its outer core, which protects life on the planet from solar winds and radiation. Understanding the evolution of Earth’s insides is crucial.
The core-mantle boundary changes from silicate to metal abruptly, and little is known about the chemical exchanges. Researchers discovered a thin layer of ‘E prime’ a few hundred kilometers thick, but its origin was unknown.
“We suggest that such chemical exchange between the core and mantle over gigayears of deep transport of water may have contributed to the formation of the putative E prime layer,” the team writes.
Seismologists found that Earth’s E prime layer has undergone unusual changes, making it less dense with slower seismic speeds.
Varying concentrations of light elements, such as hydrogen or silicon, caused these density differences. The seismic observations and dynamic stability of the layer are difficult to reconcile, but one possible theory suggests that increasing one light element’s concentration while decreasing another’s could explain the phenomenon.
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