green-agenda
July 18th, 2008, 09:21 PM
Study finds Arctic seabed afire with lava-spewing volcanoes
Wednesday, June 25, 2008
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 underwater volcanoes near the North Pole. "Explosive volatile discharge has clearly been a widespread, and ongoing, process," according to an international team that sent unmanned probes to the strange fiery world beneath the Arctic ice.
They returned with images and data showing that 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.
He and his colleagues, who describe the underwater scene in the journal Nature today, estimate that exploding mixtures of lava and gas flew out of the volcanoes at speeds of more than 500 metres a second. When the material hit the frigid seawater, Sohn says it would have formed huge clouds that rained volcanic material down on the sea floor, creating the carpet of glassy shards and bits that can be seen for kilometres.
[..]
Sohn says it would have been "spectacular to witness" the eruptions, but he says it is a good thing there is four kilometres of seawater on top of the Gakkel Ridge as the eruptions would have been "highly problematic" had they occurred on dry land.
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.
http://www.canada.com/topics/news/story.html?id=81bb2fd3-63f1-476f-b0be-f48c0dc90304
Wednesday, June 25, 2008
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 underwater volcanoes near the North Pole. "Explosive volatile discharge has clearly been a widespread, and ongoing, process," according to an international team that sent unmanned probes to the strange fiery world beneath the Arctic ice.
They returned with images and data showing that 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.
He and his colleagues, who describe the underwater scene in the journal Nature today, estimate that exploding mixtures of lava and gas flew out of the volcanoes at speeds of more than 500 metres a second. When the material hit the frigid seawater, Sohn says it would have formed huge clouds that rained volcanic material down on the sea floor, creating the carpet of glassy shards and bits that can be seen for kilometres.
[..]
Sohn says it would have been "spectacular to witness" the eruptions, but he says it is a good thing there is four kilometres of seawater on top of the Gakkel Ridge as the eruptions would have been "highly problematic" had they occurred on dry land.
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.
http://www.canada.com/topics/news/story.html?id=81bb2fd3-63f1-476f-b0be-f48c0dc90304