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Various strange phenomena have been detected around the Earth’s mantle and core.
So far, scientists have assumed the cause is due to activity occurring in the mantle layer, but recent studies suggest a different opinion. The anomalies that appear actually come from the deepest parts of our planet.
The Earth’s mantle, which is composed of silicate rocks, is bordered by a liquid outer core layer. And if you look at the seismic images, there is a fine structure between the two layers.
This study, which was published in the journal Nature, studying the activity that occurs in the outer core layer at a depth of 3,000 kilometers. This region is composed of viscous liquid iron which has a major influence on the habitability of the Earth’s surface and the formation of its magnetic field. In order to find out what’s really going on down there, the research team also conducted a simulation using similar materials in that layer.
“During the experiment, we mixed a liquid iron-hydrogen alloy with silicon at high temperature and pressure,” Suyu Fu, a geoscientist at Arizona State University, explained by email. “We observed the formation of silicon-rich crystals in liquid ferrous metal (or silicon-rich snow). This material is lighter than the liquid outer core, so it is pushed up into the layer between the liquid core and the solid mantle.”
According to Fu, silicon-rich snow could accumulate from this activity, a process that can help us understand the nature of the structure between the two layers.
“Our research sheds light on the causes of two distinct seismic wave velocity anomalies at the Earth’s core-mantle boundary, namely an ultra-slow zone on the mantle side and a rigidity zone on the core side,” he continued.
“Previously there was an assumption that the slow zone was related to mantle processes, but our observations show that this zone can also form as a result of processes occurring in the outer core. As for the rigidity zone, there is a theory that the cause is precipitation of light elements in the outer core. But the evidence we have found points to the possibility of a silicon ‘snowdrift’ phenomenon.”
The reverse-rotating Earth’s core phenomenon that was uncovered last month isn’t the only recent oddity to have hit the scientific community in recent times. In early February, scientists suggested there was a zone of Earth that had been hiding 160 km below the surface. The area had never been seen before.
Fu also explained that previous research had found volcanic rocks whose content is similar to the Earth’s core on islands such as Hawaii.
“If the very low-velocity zone could be due to a mixture of silicon-rich crystals from the Earth’s core and mantle silicate rock, then that could provide clues as to why there are volcanic rocks with materials similar to Earth’s core.”
