Satellite images reveal remains of lost continents hidden under Antarctica

8 Nov 20181.47k Views

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The latest satellite imagery from ESA has helped uncover images of the remnants of lost continents deep beneath ice sheets at Antarctica.

With incredible resources such as Google Earth available to us, we might think that we have mapped every square inch of our planet. But now, images released by the European Space Agency (ESA) to mark the fifth anniversary of the end of the Gravity Field and Ocean Circulation Explorer (GOCE) mission have revealed what is hidden beneath.

Despite it having succumbed to Earth’s gravity, the GOCE satellite is still yielding results. In a paper recently published to Scientific Reports, a team from Kiel University in Germany and the British Antarctic Survey has revealed remnants of lost continents deep under the Antarctic ice.

GOCE’s main objective was to create a high-fidelity global gravity map, or ‘geoid’. However, it was also tasked with charting localised gravity gradients – measurements of how rapidly the acceleration of gravity changes – across all directions of motion, down to a resolution of 80km.

Using the latter data, the research team converted the patchwork of 3D gravity measurements into curvature-based ‘shape indexes’ across the different regions of our planet, similar to how we see contours on a map.

By combining this with previous seismological data, the gravity gradients become extra sensitive to Earth’s lithosphere, or the planet’s crust and the molten mantle beneath it. Much of this material includes rocky zones known as cratons, which contain the remnants of ancient continents pushed inwards by plate tectonics.

A geological map of Antarctica with blue, red, yellow and green colours.

GOCE’s new curvature images help unveil the difference in lithospheric structure between the dense craton composite of East Antarctica and the rift system of West Antarctica. The blue colours indicate ‘bowl’ features and the red colours indicate ‘dome’ features. Image: Kiel University/BAS

Helps us better understand shifting ice

With Antarctica still barely inhabited and almost totally covered in ice, it remains much of a blank spot on existing geological maps.

“In East Antarctica, we see an exciting mosaic of geological features that reveal fundamental similarities and differences between the crust beneath Antarctica and other continents it was joined to until 160m years ago,” said the study’s co-author, Fausto Ferraccioli.

Meanwhile, West Antarctica has a thinner crust and lithosphere, unlike the east, which shares a ‘family likeness’ with that of Australia and India, to which it was once connected millions of years ago.

Rather than just telling an interesting story, however, these findings could help climatologists understand how Antarctica’s continental structure is influencing the behaviour of ice sheets and how rapidly Antarctica’s regions will rebound in response to melting ice.

Colm Gorey is a journalist with Siliconrepublic.com

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