Arctic seabed afire with lava-spewing volcanoes
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Arctic seabed afire
with lava-spewing volcanoes
25 Jun 08 - The Arctic seabed is as explosive geologically as it is politically judging by the "fountains" of gas and molten lava that have been blasting out of massive underwater volcanoes beneath the Arctic ice cap, scientists reported in the June 26 issue of the journal Nature.
Red-hot magma has been rising from deep inside the earth and blown the tops off dozens of submarine volcanoes, four kilometres below the ice. "Jets or fountains of material were probably blasted one, maybe even two, kilometres up into the water," says geophysicist Robert Sohn of the Woods Hole Oceanographic Institution, who led the expedition.
The eruptions took place in 1999 along the Gakkel Ridge, a mostly unexplored section of the mid-ocean ridge system that runs through the Arctic Ocean. The underwater mountain chain snakes 1,800 kilometres (1,100 miles) from the northern tip of Greenland to Siberia, making it bigger than the Himalayas.
Previous research had concluded that this kind of so-called pyroclastic eruption could not happen at such depths due to the crushing pressure of the water.
But when the scientists finally got a first-ever glimpse of the ocean floor 4,000 meters (13,000 feet) beneath the Arctic pack ice, they were astonished.
"The scale and magnitude of the explosive activity that we're seeing here dwarfs anything we've seen on other mid-ocean ridges," said Sohn, who studies ridges around the world.
"Explosive volatile discharge has clearly been a widespread, and ongoing, process."
When continental plates collide into each other, they can thrust up mountain ranges such as the Himalayas.
But along most of the mid-ocean ridge – including the Gakkel Ridge - the plates are pulling apart, allowing molten magna and gases trapped beneath the crust to escape.
The scientists say the heat released by the explosions is not contributing to the melting of the Arctic ice, but Sohn says the huge volumes of CO2 gas that belched out of the undersea volcanoes likely contributed to rising concentrations of greenhouse gases in the atmosphere. How much, he couldn't say.
"I had the impression this whole central volcano area was oozing warm fluid," says Henrietta Edmonds of the University of Texas, who was tracking the plumes of warm waters rising from the spreading ridge. The plumes point to the presence of "gushing black smokers" as well as microbial and other forms of life that can thrive in scalding, mineral-rich waters that percolates out of spreading ridges, she said
The heat released by the explosions is not contributing to
An AP article describes the explosions as being “as big as
Are we supposed to believe that some farmer’s tractor in
C'mon people, do you take us for total dummies?
By the way, I've been warning you about underwater volcanoes on the Gakkel Ridge for two years.
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