After 781 years of dormancy, the Fagradalsfjall volcano in Iceland finally went off in 2021. During its 6-month period of activity, tourists and locals alike all crept closer to take photos.
This eruption particularly piqued the interest of scientists. Since these explosions were fairly tame, scientists had easier access to the volcano vents. They wanted to know what happened below the surface of the volcano. So, on the first day of the eruptions, they collected samples of lava. The tests on the lava revealed something unexpected: there were crystals in the lava.
With the lava samples, scientists have come closer to understanding the dynamics under the surface of this oceanic volcano. In a paper published in June in the journal “Nature Communications,” researchers found a wide range of material inside the lava. These materials spanned from different parts of the mantle to the amalgamate layer between the Earth’s crust and core.
“We have a really detailed record of the different types of composition that we can find in the mantle now, and it must be very heterogeneous, very variable,” said Frances Deegan, a volcanologist at Uppsala University in Sweden and a co-author of the paper.
Dr. Deegan and Ilya Bindeman, a geochemist at the University of Oregon, worked with other researchers to analyze the lava. They found that not only were the chemicals incredibly varied over time, suggesting that many different parts of the mantle had combined in the eruption, but also that the oxygen isotopes were virtually identical across these samples. It has been theorized that the mantle takes up the isotope oxygen-18, which is a theory as to why Iceland has had such low levels of oxygen-18.
The lava was primitive, meaning that it came from a deep reservoir of magma instead of the shallow crust of the Earth. “We were working all hours — you’re asleep and the volcano’s still erupting and you’re like, ‘I got to get back out there,’” said Dr. Marshall. “But it’s hard to describe how rare this kind of thing is.”
The volcano is in between the Eurasian and North American tectonic plates. It is estimated that volcanic activity for Fagradalsfjall occurs every 1,000 years. Usually, volcanoes erupt when lots of small magma flows mix. But Olafur Flovenz, the director of the Iceland GeoSurvey, says otherwise. He suggested that this activity was not caused by a body of magma accumulating in the crust, but instead from carbon dioxide released through the pooling of magma between the mantle and the crust in the Mohorovicic discontinuity, or moho.
“For the first time, more or less, we are looking at an active eruption on our oceanic crust where the lava is directly erupting from the mantle source,” Dr. Flovenz commented on the rare spectacle. “These are very exciting times.”
This eruption particularly piqued the interest of scientists. Since these explosions were fairly tame, scientists had easier access to the volcano vents. They wanted to know what happened below the surface of the volcano. So, on the first day of the eruptions, they collected samples of lava. The tests on the lava revealed something unexpected: there were crystals in the lava.
With the lava samples, scientists have come closer to understanding the dynamics under the surface of this oceanic volcano. In a paper published in June in the journal “Nature Communications,” researchers found a wide range of material inside the lava. These materials spanned from different parts of the mantle to the amalgamate layer between the Earth’s crust and core.
“We have a really detailed record of the different types of composition that we can find in the mantle now, and it must be very heterogeneous, very variable,” said Frances Deegan, a volcanologist at Uppsala University in Sweden and a co-author of the paper.
Dr. Deegan and Ilya Bindeman, a geochemist at the University of Oregon, worked with other researchers to analyze the lava. They found that not only were the chemicals incredibly varied over time, suggesting that many different parts of the mantle had combined in the eruption, but also that the oxygen isotopes were virtually identical across these samples. It has been theorized that the mantle takes up the isotope oxygen-18, which is a theory as to why Iceland has had such low levels of oxygen-18.
The lava was primitive, meaning that it came from a deep reservoir of magma instead of the shallow crust of the Earth. “We were working all hours — you’re asleep and the volcano’s still erupting and you’re like, ‘I got to get back out there,’” said Dr. Marshall. “But it’s hard to describe how rare this kind of thing is.”
The volcano is in between the Eurasian and North American tectonic plates. It is estimated that volcanic activity for Fagradalsfjall occurs every 1,000 years. Usually, volcanoes erupt when lots of small magma flows mix. But Olafur Flovenz, the director of the Iceland GeoSurvey, says otherwise. He suggested that this activity was not caused by a body of magma accumulating in the crust, but instead from carbon dioxide released through the pooling of magma between the mantle and the crust in the Mohorovicic discontinuity, or moho.
“For the first time, more or less, we are looking at an active eruption on our oceanic crust where the lava is directly erupting from the mantle source,” Dr. Flovenz commented on the rare spectacle. “These are very exciting times.”
