Iceland volcano eruption opens a rare window into the Earth beneath our feet
The recent Fagradalsfjall eruption in the southwest of Iceland has enthralled the whole world, including nature lovers and scientists alike. The eruption was especially important as it provided geologists with a rare opportunity to study magmas that were accumulated in a deep crustal magma reservoir but ultimately derived from the Earth’s mantle (below 20 km).
This is published in a new article published in the prestigious scientific journal Nature Communications. Among the authors are the earth scientists Þorvaldur Þórðarson, professor, Ármann Höskuldsson, research professor, and William M. Moreland, adjunct lecturer, all at the University of Iceland.
A research team from USA, Sweden, Iceland, and Germany took this exceptional opportunity to collect lava samples every few days in order to construct a time-integrated catalogue of samples and to monitor the geochemical evolution throughout the eruption to a degree of detail not previously possible. Usually, when volcano scientists look at past eruptions they work with a limited view of the erupted materials – for example older lava flows can get wholly or partially buried by newer ones. However, at Fagradalsfjall, the eruption was so well monitored and sampled that scientists had a unique chance to capture the evolution of an Icelandic eruption in almost real-time.
The eruption in Fagradalsfjall was especially important as it provided geologists with a rare opportunity to study magmas that were accumulated in a deep crustal magma reservoir but ultimately derived from the Earth’s mantle as was published in a new article published in the prestigious scientific journal Nature Communications. Among the authors are the earth scientists Þorvaldur Þórðarson, professor and Ármann Höskuldsson, research professor, both at the University of Iceland.
"The team were particularly interested in oxygen isotopes," says Þorvaldur, but he and Ármann Höskuldssonspent more time at the eruption site than most other scientists.
"Why? Because oxygen makes up about 50% of all volcanic rocks and its isotope ratios are very sensitive tracers of mantle and crustal materials. But the other vast suite of elements making up the volcanic rocks also threw up some surprises," adds Þorvaldur.
Geochemical results show that the Iceland eruption was supplied by magmas derived from multiple sources in the Earth’s mantle, each with its own distinctive elemental characteristics. To the amazement of scientists, each of these domains had identical oxygen isotope ratios. This result was remarkable and has never been observed before at an active eruption. The study provides new and compelling evidence for distinct mantle-sourced lavas having uniform oxygen isotope ratios, which can help us to better understand mantle dynamics and refine mantle models for Iceland.
