Gakkel Ridge


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Gakkel Ridge

 

an underwater ridge in the Arctic Ocean between the abyssal Nansen and Amundsen depressions, the northern continuation of the Middle Atlantic Ridge. It is more than 1,000 km long and is composed of almost parallel ridges and numerous cone-shaped mountains of volcanic rocks (mainly basalts). Along the axis of the ridge there are deep canyons 20-30 km wide that form a rift valley. The summits of the ridge rise up to 4,000 m above the bottom of the ocean; the minimum known depth above the ridge is 400 m (the Lenin Komsomol Seamount). There is underwater volcanic and earthquake activity. The ridge was named in honor of its discoverer, Ia. Ia. Gakkel’.

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In their study, the team analysed common minerals such as olivine and plagioclase which grew deep within the volcanoes and were subsequently erupted from the Gakkel Ridge located beneath the Arctic Ocean between Greenland and Siberia.
Yet the new data has shown that the plumbing system extends to at least 16 km depth, which means that the magma chambers that fed the Gakkel Ridge volcanoes are located much deeper down in the mantle.
The revised application includes the southern tip of the Gakkel Ridge as well as the Podvodnikov Basin and the area under the North Pole as Russia argues the areas belong to its continental shelf.
Researchers found jagged, glassy fragments of rock (called pyroclastic deposits) spread out over a 6.2-square-mile (10-square-kilometer) area around a series of small volcanic craters on the Gakkel Ridge. The area is a remote, mostly unexplored part of the mid-ocean ridge, the volcanic undersea mountain chain that wraps around the globe.
Under the ice and 2 kilometers of water was a 1,800-km-long underwater mountain range known as the Gakkel Ridge. The Healy's expedition, conducted in tandem with the German icebreaker Polarstern, was the first exploration to that Arctic ridge to attempt to collect geological samples.
Their dual missions: to test experimental vehicles specially designed and built by WHOI engineers for use in ice-covered oceans and to use them to search for volcanic activity and new deep-sea life forms on the previously unexplored Gakkel Ridge. Thousands of people followed daily dispatches of the unfolding expedition on two WHOI Web sites: Dive and Discover and Polar Discovery.
In 2001, she and other scientists used icebreakers to plow their way across the Arctic Ocean to make measurements along a 1,100-kilometer segment of the 1,800-km-long Gakkel Ridge. That little-explored midocean ridge, which is spreading slower than other known seams, runs within 350 km of the North Pole and lies at frigid depths between 4,500 and 5,000 meters.
Microbiologist Elisabeth Helmke from the Alfred Wegener Institute in Germany (above right) scrapes orange deposits from a Gakkel Ridge rock snatched up by Camper's grabber.
Our mission will be to use AUVs to find, map, and sample hydrothermal vent fields on the Gakkel Ridge. We will develop instrumentation that will guide future efforts to search for life on Europa, a Galilean moon of Jupiter, which may have two necessary ingredients for life: active volcanism and an ocean--albeit an ice-covered one.
We made the first detailed maps of large portions of the Gakkel Ridge, which extends from north of Greenland almost to Siberia.
Expeditions to the Southwest Indian Ridge in 2000 and the Gakkel Ridge (under the Arctic Ocean) in 2001 revealed that hydrothermal venting occurs on even the slowest spreading portions of the mid-ocean ridge system.
icebreaker Healy found evidence from water samples and seafloor rocks of far more volcanism and hydrothermal venting than was predicted on the ultra-slow-spreading Gakkel Ridge in the Arctic Ocean.