Why Greenland is Covered in Ice: Processes Deep Beneath Earth's Surface

Why is Greenland covered in ice? Scientists have taken a closer look, and have found that the ice on Greenland could only form due to processes deep in the Earth's interior.

About 2.7 million years ago, large-scale glaciations began in the Arctic. Before that, though, the northern hemisphere was largely free of ice for more than 500 million years. That's why scientists decided to find out why the conditions for the glaciation of Greenland developed so recently on a geological time scale.

The answer to this question lay within rock samples. Scientists found hints that the high mountains in the east of Greenland were only uplifted during the last ten million years. In fact, this process happened especially fast, in terms of shifting geologic processes. Before this uplifting, Greenland was largely free of ice, and seismological investigations indicate that hot rocks rose beneath Iceland from Earth's deep mantle.

The researchers also found that the lithosphere in the East of Greenland is especially thin-only about 90 kilometers thick. The researchers used this information and then reconstructed the position of the tectonic plates 60 to 30 million years ago. This showed that the Iceland plume was beneath this part of Greenland during that time. This explains why the lithosphere is so thin, and reveals why the eastern part of Greenland could be more easily uplifted.

Over the years, though, the plates shifted and pushed Greenland northward. This, in combination with the higher mountaintops, allowed glaciations to occur.

The findings reveal exactly how Greenland became covered with ice over time. It turns out that tectonic plates had a much larger role to play than previously thought.

The findings are published in the journal Terra Nova.

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