The interior of the Earth has countless mysteries hidden in its folds. Of all the ongoing processes thousands of kilometers beneath our feet, however, seismic waves are among the most pressing and complex mysteries to decode. Now, however, a new discovery may shed light on the inconsistent behavior of seismic waves while improving our understanding of changes in the Earth’s magnetic field.
The discovery in question was made by scientists from Arizona State University, who recently discovered a new layer of silicon-rich ‘snow’. It exists about 3,000 kilometers below our feet, rising from Earth’s liquid iron alloy outer core and flowing to the mantle.
Mysterious Snow Layer And Its Connection To Seismic Waves
In light of the devastating earthquakes that continue to rock Turkey and Syria, the discovery of this snowy blanket of silicon may help us demystify the anomalies observed in the seismic activity that scientists have recorded while scanning the mysteries of the deep Earth.
These “silicon snowflakes” are lighter than the surrounding molten iron and tend to rise and flow upward toward the mantle. As the crystals flow from the metallic core into the rock mantle, the silicon snow can settle in drifts, creating fine structures that cause sound waves to distort in unpredictable ways.
But this upwardly moving silicon-rich snow is only possible if “silicon and hydrogen are the two main light elements in the outermost core with corresponding abundances,” says geologist Suyu Fu of the University of Tokyo. Simulation of silicon snow from the Earth’s interior in the laboratory To verify this, the study team recreated conditions similar to the outer core in the laboratory.
They started by placing an iron-silicon alloy in a mixture of hydrogen and argon, then ultra-compressed it inside a diamond anvil at a pressure equal to that of the outer core and heated the assembly to outer-core temperatures using laser beams. .
By monitoring the experiment with bright X-rays, the study team observed the formation of silicon-rich crystalline “snow”. It was not the first time that researchers tried to simulate a snowy layer on the Earth’s surface. Previously, they loaded an alloy of iron and silicon into a gaseous hydrogen mixture. However, hydrogen would diffuse into the diamond anvil at temperatures similar to the outer core, making it difficult to observe silicon crystallization.
But this time, by adding non-reactive argon to the mix, this tendency for hydrogen diffusion was suppressed, and the team could finally replicate the formation of silica snow! “It is interesting that such crystallization behavior can lead to rising silicon-rich snow in the outer core,” says geologist Sang-Heon Dan Shim, co-author of the paper.
These movements in our planet’s outer core also control Earth’s magnetic field, which casts a protective shield over deflecting the damaging effects of outer space and solar weather. Understanding the workings of our planet’s core is therefore essential to understanding how the Earth’s magnetic field works and how it will transform in the future.
