Fountains of diamonds erupt from the ground when continents break up, say scientists — and it could help uncover new deposits

• Diamonds can gush to the surface in violent eruptions.
• These eruptions have baffled scientists as they happen more often after continents break up. 
• A new study provides an explanation, and it could help miners find more sources of diamonds.

Millions of years ago, diamonds erupted from deep underground onto Earth's surface in huge, volcanic explosions that reached speeds of more than 80 miles per hour.

These powerful eruptions, and what triggered them, have long baffled scientists.

The question is "why on Earth do they shoot up from the deep after spending potentially billions of years sat there?" Tom Ger non, a geologist at the University of Southampton who led a study on the topic, told The Guardian.

Now, researchers think they have an explanation. Based on computer models, they believe these eruptions may have been triggered by the breakup of supercontinents.

The discovery, they claim, could help miners in their search for undiscovered diamond deposits.

Diamonds can erupt to the surface

Scientists have known for some time that a special form of magma called kimberlite can rip through the Earth's core at staggering speeds carrying diamonds.

This magma is rich in gases carbon dioxide and water. That propels it from the depths of the Earth, like soda gushing from a bottle that has been shaken too much.

This magma can pick up diamonds along the way as it bubbles to the surface. This creates diamond-rich areas, that are ripe for mining. 

However, if you're thinking of planning your next holiday to see a diamond eruption, think again. No human in history has seen one of these happen, and that's because these tend to happen near a time of great continental disruption, like when Pangaea broke apart about 200 million years ago.

The most recent eruption of this kind is believed to have taken place 11,000 years ago, according to The Guardian.

"The pattern of diamond eruptions is cyclical, mimicking the rhythm of the supercontinents, which assemble and break up in a repeated pattern over time," Gernon said.

In fact, scientists found that most kimberlite volcanoes occurred 20 to 30 million years after the tectonic breakup of Earth's continents.

The continental divide stretches the Earth's crust like pizza dough

You would expect the kimberlite to erupt near the borders of the continent, where the plates are being ripped apart by the continental divide.

But instead, it tends to appear in "a sweet spot in the interior of continents where diamonds form," Gernon said. 

By analyzing the eruptions more closely, scientists think they've cracked this mystery. And it's down to a "domino effect," that churns the kimberlite closer and closer to the center of continents, Stephen Jones, co-author on the study and Professor of geology at the University of Birmingham, said in the statement. 

As continents are pulled apart by the divide, it stretches the Earth's crust like a pizza dough. That thinning causes the crust to sink into the Earth's mantle below.

This interaction rips off big chunks of the rock from the continental plate. As these drop into the mantle, they drive a churning motion beneath the continent, said Jones. 

"Remarkably, this process brings together the necessary ingredients in the right amounts to trigger just enough melting to generate kimberlites," said Gernon. 

The scientists say having uncovered this chain reaction could help discover diamond deposits in the future.

But it also shows how the Earth's interior interacts with the Earth's surface — and notably how it could interact with our environment and the climate, said Gernon who says he'll be studying this relationship more closely. The diamonds in the kimberlite, he said, "might be just a part of the story," said Gernon. 

The study was published in the peer-reviewed journal Nature on July 26.