Guest Videos: Gakkel Ridge Volcanoes

Gakkel Rise, between Greenland and Siberia, is named after the Soviet geoscientist who first mapped the Arctic Ocean’s floor. It’s a long, underwater mountain range that hosts a complex of volcanoes with delightful names like Jessica’s Hill, Duque’s Hill, Oden, Thor, and Loke (not the Marvel spellings of “Odin” and “Loki,” but the same Norse-god reference).



While at least some of these volcanoes are active, Jessica and friends sit roughly 13,000 feet (4000 meters) below sea level–too far down to influence pack ice in any way.

The last known eruption, probably in 1999, scattered debris over Oden and Loke. A 2007 remote submarine expedition also found recent pyroclastic deposits, though that is not recognized as another eruption.

These were history-making discoveries. Until then, volcanologists hadn’t known that explosive eruptions can happen at such depths (slightly below the RMS Titanic wreck’s depth), where pressure is almost 400 times that on the sea surface.



But the Gakkel Rise has always surprised scientists, at first in the 1950s by being pretty much exactly where Yakov Yakovlevich Gakkel predicted it would be found.

When the plate tectonics era dawned, this northern extension of the Mid-Atlantic Ridge–a spreading center–was considered to be nonvolcanic. However, in 1999, nuclear subs detected volcanic activity there, and today Gakkel Ridge is known to be the slowest spreading center in the world–much slower than the Mid-Atlantic Ridge, and even more of a slowpoke than the Mid-Cayman and Southwest Indian ultraslow spreading ridges.



The potential mineral wealth that he mentions at the end of the video complicates the picture. Along with untapped gas and oil deposits, it’s a major motivating factor in the Arctic territorial claims we mentioned in yesterday’s post about the namesake of nearby Lomonosov Ridge.

The area needs exploration for scientific reasons, not just for geopolitical advantages.

What little is already known about Gakkel Rise volcanism is unusual. There may even be a giant caldera there, although I have only found one reference to it. I don’t know whether that’s because it is such a new paper (2017) or because this might not be a widely accepted hypothesis yet.

Anyway, as another WordPress blogger says (in a much better post):

The Gakkel Ridge is one of the most remote tectonic regions on the planet. Yet it has volcanic activity and life. It is a spreading center that connects the active Mid Atlantic Ridge to the non-spreading Eurasian Plate. Not unexpectedly, volcanic activity is found closer to the MAR, though hydrothermal vents are found in the half of the ridge closest to Greenland and the MAR. It is home to the deepest pyroclastic activity ever observed. It also has some of the thinnest oceanic crust ever observed and may even have mantle rocks exposed to the ocean. Like all our volcanic regions, the more we look at this, the more we find things that we never expected. Which is why we do this.



Sources:

Moran, K.; Backman, J.; Brinkhuis, H.; Clemens, S. C.; and others. 2006. The Cenozoic palaeoenvironment of the Arctic Ocean. Nature, 441(7093): 601.

Nikishin, A. M.; Gaina, C.; Petrov, E. I.; Malyshev, N. A.; and Freiman, S. I. 2017. Eurasia Basin and Gakkel Ridge, Arctic Ocean: Crustal asymmetry, ultra-slow spreading and continental rifting revealed by new seismic data. Tectonophysics, via PDF.

Piskarev, A., & Elkina, D. (2017). Giant caldera in the Arctic Ocean: Evidence of the catastrophic eruptive event. Scientific Reports, 7, 46248.


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