© Doug WeinsMount Sidley is the youngest volcano rising above the ice in West Antarctica's Executive Committee Range. A group of seismologists have detected new volcanic activity under the ice about 30 miles ahead of Mount Sidley.
The possible hotspot - a plume of superheated rock rising from Earth's mantle - sits under Marie Byrd Land, a broad dome at West Antarctica's edge where many active volcanoes above and below the ice spit lava and ash. The hot zone was discovered with seismic imaging techniques that rely on earthquake waves to build pictures of Earth's inner layers, similar to how a CT scan works. Beneath Marie Byrd Land, earthquake waves slow down, suggesting the mantle here is warmer than surrounding rocks. The strongest low-velocity zone sits below Marie Byrd Land's Executive Committee Range, directly under the Mount Sidley volcano, said Andrew Lloyd, a graduate student at Washington University in St. Louis.
"The slow velocities suggest that it's a mantle hotspot," Lloyd said. The hot zone also matches up with Marie Byrd Land's high topography and active volcanoes, Lloyd said. [WATCH LIVE: News on Earth & Mars at AGU 2013]
Mantle Plume?
Many researchers have long suspected that Marie Byrd Land sits atop a hotspot, because the region swells above the surrounding topography like the top of a warm soufflé (and it has lots of volcanoes). But with few seismometers sitting on the ice, scientists were left speculating about what lies beneath Antarctica's ice.
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