Scientists learn to better understand the movement of Greenland, as it was slowly pushed over the hotspot that is now located under neighboring Iceland. Nothing stands still over geologic time, and even the biggest land masses are constantly being reshaped by Earth.
Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson Beck, Ernie Wright
Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson Beck, Ernie Wright
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00:00We tend to think of Earth's landmasses as being fixed in place,
00:04but in reality, they are attached to moving tectonic plates
00:08that constantly jostle for position and slide over the more viscous mantle beneath.
00:12Case in point, Iceland.
00:16Volcanic eruptions are common on this young landmass, driven by the two tectonic plates
00:20that divide it, and by its location above a hotspot, an upwelling of magma
00:24that protrudes from deep in the mantle up to the crust.
00:28This hotspot fuels Iceland's eruptions today,
00:32but millions of years ago, it was situated beneath neighboring Greenland.
00:36Now, a NASA scientist and her colleagues have used anomalies
00:40in Greenland's crustal magnetic field to derive its geothermal heat flux.
00:44The researchers also analyzed gravity data
00:48and other geophysical information to effectively peer beneath Greenland's
00:52kilometers-thick ice sheet and into the crust itself.
00:56What they found was a thermal track in Greenland's bedrock that records the motions
01:00of a continent over geologic time.
01:04Greenland is part of the North American tectonic plate.
01:08For tens of millions of years, the plate's movement pushed Greenland over the hotspot.
01:12When the hotspot emerged at the Denmark Strait, it began raising the seafloor to form Iceland.
01:16Today, a channel of warm bedrock marks the ancient path of the hotspot,
01:20a reminder that nothing stands still over geologic time
01:24and that even the largest landmasses are constantly being reshaped
01:28by our dynamic planet.
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