Strange things are going on under our feet. Over the years, seismic studies have found a number of strange things happening between the Earth’s core and mantle. Scientists thought that these things were caused by something happening on the cover. A new study in Nature on Wednesday suggests that this activity may be related to the Earth’s core.
In the study, the authors explain that the boundary between the Earth’s core and mantle is an interface between the solid silicate mantle and the liquid metallic outer core. Understanding the structure and movement of this area is critical to understanding how heat and materials move around on our planet. Using seismology, scientists have found small systems at the boundary between the Earth’s core and mantle. Compared to the standard cover or core region around them, these “anomalies” have different speeds and densities.
This study was mainly about the Earth’s outer core, about 3000 km below the surface. The area is made up of thick liquid iron alloy, which significantly affects whether the Earth’s surface is habitable and how its magnetic field is made. Researchers can’t get to the core itself, but they can study similar conditions in a lab, which is what the authors of this study did.
“We did tests to see what happens when we mix iron-hydrogen alloy liquid with silicon at high pressure and high temperature, like in the outer core,” Suyu Fu, a geoscientist at Arizona State University and one of the study’s authors, told Motherboard in an email. “We found silicon-rich crystals in the iron metal liquid (or silicon-rich snow). These crystals are lighter than the outer core liquid, so they rise to the boundary between the metallic core and the rocky mantle instead of sinking.
Fu said that this process could make a pile of silicon-rich snow, which can help us figure out some strange structures at the boundary between the Earth’s core and mantle.
“Our study sheds light on what causes the ultra-slow zones on the mantle side and the core rigidity zone on the core side,” he wrote.
“People used to think that processes mostly caused the slow zones in the mantle, but our research suggests that processes may cause some in the outer core.” Some scientists think that light elements falling out of the outer core could cause the rigidity zone in the body. We found evidence that the core rigidity zone could be caused by a process called the “snowing” of silicon.
Even though the Earth is under our feet, we still don’t know much about its insides, especially its core. Scientists just published a study last month that suggests the core has stopped moving and may be changing direction. This would explain a number of cyclical events. And recently, scientists found a whole area 100 miles below the surface of the Earth that had never been seen before.
The new findings could help us learn how the deep Earth works chemically. Fu said that research has shown that some volcanic rocks on ocean islands like Hawaii have a chemical signature similar to the Earth’s core.
“Our study suggests that if silicon-rich crystals from the Earth’s core mix with silicates from the mantle to form these ultra-low velocity zones, they could be the source of the chemical signatures found in volcanic rocks similar to those in the core.”
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