Volcanoes of IcelandThis is a pretty simple overview map of Iceland showing the location of its volc

Volcanoes of IcelandThis is a pretty simple overview map of Iceland showing the location of its volcanoes. A few days ago, I noted that a volcano from the interior of Iceland, Bárðarbunga, appears to be waking up (http://tinyurl.com/nwwrqp5). Let’s talk a bit about where and why there are volcanoes on Iceland in the first place.Iceland is a fairly unique setting that combines 2 of the major causes of volcanoes: a mid-ocean ridge and a hotspot. Hotspot volcanoes occur in the middle of tectonic plates, forming oceanic islands and sometimes-large volcanoes like Yellowstone in the middle of continents. Most scientists believe mantle plumes cause them: blobs of warm material rising up from deep within the Earth’s mantle.Mid-ocean ridges, on the other hand, seem to be more passive features. As plates around the planet’s surface, some of them move apart, creating space in-between where mantle material can rise up. The decreasing pressure on the rocks causes them to melt, generating magmas along the ocean floor for much of the length of the globe.Near Reykjavik, the Mid-Atlantic ridge comes on shore in Iceland. The Reykjanes peninsula and the western volcanic zone are today the on-shore expression of the mid-Atlantic ridge.The western volcanic zone today does not reach the northern coast of Iceland. Instead, volcanism steps to the East and forms particularly high volcanoes over the island’s center. Today, this area, the Eastern volcanic zone, is the center of the hotspot-associated volcanism and Bárðarbunga is in this zone.The hotspot center is actually migrating relative to the mid-ocean ridge with time. You can see the evidence of it in this image; the Snæfellsnes volcanic zone is a peninsula where volcanic activity is waning. Millions of years ago, this was the center of the plume; it has since migrated to the East, and as it goes it is dragging the mid-ocean ridge with it. You can see this happening also; volcanoes like Heimeay and Surtsey are probably the expression of the plume starting to drag the mid-Atlantic ridge farther to the East off the Icelandic coastline.-JBBImage credit: http://en.wikipedia.org/wiki/Volcanology_of_Iceland#mediaviewer/File:Volcanic_system_of_Iceland-Map-en.svg -- source link
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