Volcano under the Arctic ice

The team, led by Woods Hole Oceanographic Institute (WHOI), recently found evidence of a volcanic eruption deep beneath the ice-covered white surface of the Arctic Ocean.

It is not assumed that the strong eruption of soil crumbs - also known as sediments created by volcanic lava could occur at great depths in the ocean because of the enormous mass and pressure of water along the structure of ghosts and rock under the seabed.

Researchers found rocky pieces like sharp-edged glass scattered throughout the area of ​​10 km ² (4 square miles) around a small series of volcanic craters beneath the sea surface of 4,000m (2 , 5 miles). The craters are distributed along the Gakkel Ridge - a remote, almost untapped area of ​​the mid-ocean mountain system that surrounds the Arctic Ocean.

The WHOI geophysicist Rob Reves-Sohn and the author and principal researcher of the volcanic exploratory program at Arctic Gakkel Arctic Vents Expedition (AGAVE) in July 2007 said: 'This is low. The area created by the volcanic lava we found for the first time in such a deep water area, with tremendous pressure that prevented the creation of steam, many thought that this could not happen. . That means that the intense CO ₂ flow has been released into the water column during the eruption '.

The article, which was attended by 22 investigators from nine research institutes in four countries, was published in the June 26 issue of the journal Nature.

A seismic meter alone buried in the ice of the ocean.(Photo: Vera Schlindwein, Alfred Wegener Institute)

The undersea volcano usually releases ghost seams instead of volcanoes, water vapor and rock like volcanoes on land. Due to the hydrostatic pressure of seawater, ocean eruptions are more like the eruption of Kilauea volcano than Mount Saint Helens or Mount Pinatubo.

This is the third expedition to the Gakkel range and the first expedition to study the seabed. Researchers have used a lot of combined research methods, cameras, seabed samples to collect samples of rocks and sediments, in addition to dozens of hours of high-definition movies. They found rough debris along with a bit of basalt over the seabed, distributed in every direction from the craters they had discovered and named Loke, Oden, and Thor.

They also found that there was a surface sediment on the relatively new lava layer and high surfaces like the Duque Hill and Jessica Hill, which showed the debris deposited in the water rather than the lava flow erupting from the mountain. fire. A more detailed analysis shows that some small pieces are sharp-edged cool glass that volcanic experts call 'Pele's seaweed' . They are formed when the lava is thinly covered on air bubbles spreading during the eruption. Reves - Sohn and colleagues found that larger blocks of rock, also known as talus, may have spurted out from the explosion on the sea floor.

The surface of the earth is made up mainly of the oceanic crust formed under the effect of volcanoes along the mountains in the middle of the ocean beneath the sea. Volcanic processes are associated with the rise of ghosts from the mantle along with the spread of Earth's tectonic plates. Deep in a few kilometers in the cold water, the volcanic phenomena of the mountains in the middle of the ocean are quite gentle compared to the volcanic activity on the mainland. Until now, only scattered information about volcanic activities in the sea bottom has been obtained, mainly in shallow waters. Samples of sediments and rock obtained through other expeditions have suggested the possibility of volcanic activity at depths of up to 3,000m, but the ability of volcanic eruptions at greater depths is also expected. fragile.

A major cause is the enormous pressure created by the mass of seawater, also called hydrostatic pressure. More importantly, it is very difficult to create the steam or carbon dioxide in the magma necessary to explode the rock mass through the water column. While energy requires to perform air activity a lot less. In fact, the formation of carbon dioxide in magma at the seabed needs to be 10 times the amount found in the seabed rock sample.

The results from the expedition of the Gakkel Mountains indicate that volcanic eruptions in the deep sea can and have actually happened. Reves-Sohn said: 'The circulation and depth of the Gakkel range may vary. There must be more gas involved in the system than we thought . ' The research team hypothesized that excess gas formed in the form of foam or scum near the ceiling of the ghost room under the crust, waiting to explode like champagne corked down by cork. 'Is the eruption created by the volcanic lava more common than we think, or does it have any special characteristics along the Gakkel range? That's the next question we need to answer. '

The Office of Polar Research for National Science Foundation supported the Arctic Gakkel Vents Expedition expedition. There is also the Oceanographic division of the National Science Foundation, the Gordon Center for Substrate Imaging and Imaging Systems (Gordon Center for Subsurface Sensing and Imaging Systems), the Technical Research Center of the Science Foundation. nation, NASA space biology program and WHOI Ocean Exploration Institute.