Greenland on the move

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    ID: 4670 Visualization

    Geothermal Heat Flux Reveals the Iceland Hotspot Track underneath Greenland

    Aug. 1st, 2018
    (updated Aug. 25th, 2023)

    This visualization shows the Greenland geothermal heat flux map, the track of the Iceland hotspot through Greenland, and the plate tectonic motion of Greenland over the hotspot during the past 100 million years.This video is also on the NASA YouTube channel. || Geothermal heat flux (GHF) is the amount of heat flowing outward from the interior of the Earth as measured at different points on the surface. GHF can play an important role in the motion of glaciers in places like Greenland, but the ice can also make GHF difficult to measure directly. The ice sheet covering Greenland is up to three kilometers thick, so GHF there has been measured in only a few places where deep boreholes have been drilled through the ice.In a paper published in Geophysical Research Letters, NASA Goddard research scientist Yasmina Martos and her coauthors describe a method of mapping GHF across Greenland using a map of magnetic anomaly, the local variations in the Earth's magnetic field. Temperature affects the magnetic record stored in minerals in the Earth's crust, and using this fact, Martos et al. were able to infer a high-resolution map of GHF for Greenland and neighboring Ellesmere Island. Crustal thickness data derived from gravity measurements supports the conclusions.The GHF map contains at least two surprises. The overall GHF is lower than expected, and the map reveals a warm swath across Greenland from the northwest to the southeast. The swath is likely to be the track of the Iceland hotspot, a plume of magma rising from deep within the Earth's mantle. The hotspot is responsible for the formation of Iceland, beginning roughly 20 million years ago, in a manner similar to the formation of the Hawaiian islands. The track of the hotspot through Greenland actually records the motion of Greenland over the last 100 million years as plate tectonics moved it north and west.This visualization shows the GHF map, the hotspot track, and the motion of Greenland. ||

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  • 
    ID: 13025 Produced Video

    NASA Scientist Reveals Greenland's Geologic Past

    Aug. 1st, 2018
    (updated May 3rd, 2023)

    A new map of Greenland's geothermal heat flux is helping to reveal the path of the North American tectonic plate over geologic time. Complete transcript available.Watch this video on the NASA Goddard YouTube channel.Music Provided by Killer Tracks: "Valfri" by James Alexander Dorman || We tend to think of Earth's landmasses as being fixed in place, but in reality they are attached to moving tectonic plates that constantly jostle for position. In some areas these tectonic plates slide over a hotspot – an upwelling of magma from deep in the mantle that can leave behind a geologic "scar" in the crust.Now, a NASA scientist and her colleagues have used anomalies in Greenland's crustal magnetic field to derive its geothermal heat flux, allowing them to effectively peer beneath Greenland's thick ice sheet and into the crust itself. What they found was a thermal track in Greenland's bedrock that records the motions of the North American tectonic plate over geologic time.This finding helps scientists to better understand the movement of Greenland, as it was slowly pushed over the hotspot that is now located under neighboring Iceland. It also serves as a reminder that nothing stands still over geologic time, and that even the largest landmasses are constantly being reshaped by our dynamic planet.Learn more about this finding. ||

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