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In Iceland, a Volcanic Eruption Brings Researchers Closer to Earth’s Core


What do you do when a volcano erupts for the primary time in centuries?

For many individuals on the southern peninsula in Iceland, when the Fagradalsfjall volcano went off in 2021 after 781 years of dormancy, the reply was to take pictures. Because the eruption continued over the course of six months, tourists and locals traveled closer to the volcano to take much more. Red bursts flying out of a black pyramid; the viscous creep of flame.

But this documentation only went up to now. Some scientists desired to know what was happening underneath the surface, miles deep, where light doesn’t reach. There, the flowing rock works in ways in which experts still cannot describe. So on the primary day of the eruption, a helicopter flew out to the location and scooped up a little bit of lava. Some samples were distributed to labs, which, after testing, sent back unexpected results: The lava was filled with crystals.

Recently, with the assistance of comparable samples gathered throughout the Fagradalsfjall eruption, steps have been taken toward characterizing the dynamics under the surface of the oceanic volcano. In a paper published in June within the journal Nature Communications, researchers who observed the chemical composition of the lava crystal samples collected over a six-month period found that they contained a big selection of fabric from different parts of the mantle, the amalgamate layer between the Earth’s crust and core. This sort of variation was unexpected, and it painted a more vivid picture of what contributes to volcanic eruptions.

“We have now a very detailed record of the different sorts of composition that we are able to find within the mantle now, and it have to be very heterogeneous, very variable,” said Frances Deegan, a volcanologist at Uppsala University in Sweden, and a co-author of the paper.

Compositionally, the Fagradalsfjall lava was primitive, meaning it got here from a deep reservoir of magma, or underground lava, not a shallow reservoir within the Earth’s crust. Noticing this, researchers, including Ed Marshall, a geochemist on the University of Iceland, sprinted to assemble more samples because the lava continued to spew out of vents. “We were working all hours — you’re asleep and the volcano’s still erupting and also you’re like, ‘I got to get back on the market,’” said Dr. Marshall. “Nevertheless it’s hard to explain how rare this sort of thing is.”

Fagradalsfjall exists at a confluence of fault lines along a boundary between the Eurasian and North American tectonic plates, some extent where they’re each pulling apart and rubbing against one another. Geological records show that there was periodic volcanic activity within the region about every thousand years, and this most up-to-date fissure was preceded by greater than a yr of earthquakes. Olafur Flovenz, director of the Iceland GeoSurvey, recently published a paper with colleagues that means this activity was not brought on by a body of magma accumulating within the crust, but from carbon dioxide released by deeper magma pooling between the mantle and the crust, in a region called the Mohorovicic discontinuity, or moho.

Normally, volcanic eruptions occur when plenty of small magma flows mix together. “This mixing process is a vital geologic process, but it surely’s never been directly observed,” said Dr. Marshall. It occurs so deep under the surface and most of the chemical signatures of individual flows are lost because the magma moves up through the crust. But when Fagradalsfjall erupted in 2021, the molten rock and crystals that shot as much as the surface got here directly from the moho. “For the primary time, roughly, we’re taking a look at an energetic eruption on our oceanic crust where the lava is directly erupting from the mantle source,” Dr. Flovenz said.

In comparison with other oceanic volcanoes, Fagradalsfjall’s vents were relatively easy to access, and its 2021 eruption was fairly tame. Researchers like Dr. Marshall, who didn’t contribute to either paper but has a forthcoming article on the identical subject with a gaggle of collaborators on the University of Iceland, say these studies could essentially reach right into the mantle and capture otherwise hidden dynamic processes “like lightning in a bottle.”

Dr. Deegan and her collaborator, Ilya Bindeman, a geochemist on the University of Oregon, worked with other researchers on the bottom at Fagradalsfjall to research the lava. They found that not only were the chemicals incredibly varied over time, suggesting that many various parts of the mantle had combined within the eruption, but additionally that the oxygen isotopes were virtually equivalent across these samples. This contributes to an extended standing technical inquiry into the source of Iceland’s mysteriously low levels of oxygen-18, an isotope often present in volcanic rock. Dr. Bindeman said that scientists have been debating for greater than half a century whether this might be attributed to a scarcity of the isotope within the mantle. “We found that the depletion happens some place else,” he said.

Dr. Marshall and his colleagues have also been using the lava samples to explain mixing and melting processes in magma reservoirs, which was not done in essentially the most recent paper.

“These are very exciting times,” said Dr. Flovenz, who began studying Icelandic volcanoes in 1973. “I had never had the hope that I’d live to see this unrest and eruptions on this peninsula. This has been extremely interesting for the geosciences community.”

“It’s a completely amazing eruption for our field,” said Dr. Marshall, “and it’s one in every of those things that can be studied for a very long time.”

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