Diamond fountains erupt
Diamonds are known to spew from deep under the Earth’s surface in the form of powerful, explosive volcanic eruptions.
Supercontinental disintegration may result in violent eruptions that send fountains of diamonds shooting up to the Earth’s surface.
About 93 miles (150 km) underground in the Earth’s crust, diamonds are formed. They are swiftly raised to the surface in eruptions known as kimberlites. According to Thomas Gernon, a professor of Earth and climate science at the University of Southampton in England, some eruptions of these kimberlites may have produced bursts of gases and dust resembling that of Mount Vesuvius. These kimberlites move at speeds between 11 and 83 mph (18 and 133 km/h).
According to research, kimberlites tend to form more frequently when the tectonic plates are significantly realigning themselves, such as during the breakup of the supercontinent Pangaea. Strangely, though, kimberlites frequently erupt in the center of continents rather than at their edges, and this internal crust is solid, resilient, and difficult to disturb.
Since hundreds of millions or possibly billions of years ago, the diamonds have been lying in the foot of the continents, according to Gernon. “These eruptions themselves are really powerful and explosive, so there must be some stimulus that just drives them suddenly.”
Gernon and his associates started by trying to find links between the ages of kimberlites and how much plate fragmentation was taking place at those times. They discovered a trend in the previous 500 million years when the plates begin to separate, and 22 to 30 million years later, kimberlite eruptions reach their climax. (This pattern also held for the last 1 billion years, albeit with greater uncertainty due to the challenges involved in dating geologic cycles back that far.)
As an illustration, the scientists discovered that kimberlite eruptions began to increase in what is now Africa and South America about 25 million years after the southern supercontinent Gondwana split apart about 180 million years ago. Kimberlite deposits also increased in today’s North America once Pangaea started to split apart some 250 million years ago. It’s interesting to note that these kimberlite eruptions appeared to begin near the rift’s margins before moving continuously in that direction.
The researchers employed numerous computer models of the deep crust and upper mantle to determine what was causing these patterns. They discovered that as tectonic plates separate, the continental crust at its base thins, while the crust on top spreads out and creates valleys. Localized zones of circulation are produced as hot rock rises, contacts the boundary, cools, and sinks once more.
These unstable zones have the potential to spread instability hundreds of miles out toward the continent’s center. According to research published on July 26 in the journal Nature, this discovery is consistent with the real-world pattern of kimberlite eruptions that begin close to rift zones before migrating to continental interiors.
But how do these instability-related explosive crustal eruptions occur? It all comes down to mixing the ideal components, according to Gernon. Rock from the upper mantle and lower crust can collide with one another due to the instabilities.
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This stirs up rock that contains significant amounts of water and carbon dioxide as well as several essential kimberlite minerals, including diamonds. Gernon compared the outcome to shaking a bottle of champagne: explosive eruptions that are propelled to the surface by buoyancy.
According to Gernon, the information could be beneficial in the quest for untapped diamond reserves. They could also contribute to the understanding of other sorts of volcanic eruptions that occasionally take place in areas that ought to be mainly stable long after a supercontinent has split.
“It’s a fundamental and highly organized physical process,” Gernon said. “So it’s likely not just kimberlites responding to it, but it could be a whole array of Earth system processes that are responding to this as well.”