ESA: Long-Lost Continents Under Antarctica Are Revealed by Satellite Images
Ice has made the continent hard to map, but new satellite imaging changes that.
by Tiffany JeungUnfortunately, scientists haven’t find a frozen Atlantis, but newly released research signals a breakthrough for an even bigger mystery: The geography of Antarctica.
Using data collecting by the ESA’s Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite, a team from Kiel University and the British Antarctic Survey has compiled maps of Earth’s gravity levels, revealing the icy continent’s ancient history. With the trove of new data, scientists can not only fill in the history books, but better understand how of ice sheets move as a result of a changing, warming climate. Their research was published paper published this week in the journal Scientific Reports.
To measure an entire continent, you have to zoom out — a lot — which is where the GOCE satellite played a key role. After launching from Russia in March 2009, GOCE spent the next four years and eight months about 250 kilometers above Earth, measuring the subtle differences in “gravity gradients, “or how much gravity accelerates, below. From the data, researchers can distill key information about the Earth’s lithosphere, the crust and uppermost mantle that make up the rigid outer layer of the planet.
The Earth's gravity isn't consistently the 9.8 meters per second, squared your first physics class said. We're a bit lumpy.
Direct gravity measurements step beyond seismic imaging, which uses the ricochet of sound waves to draw maps of regions underground, since locations with similar seismic images may actually have different gravity gradients. We literally have a deeper understanding of the Earth’s outer layers.
The complex measurements are difficult to comprehend, so the team transformed the data into gravity indices that can be plotted on a map — which is where Antarctica’s history finally surfaces.
Ninety-eight percent of Antarctica is covered by two kilometers of ice, which previously left the continent’s difficult-to-measure topography as a massive data gap.
Fausto Ferraccioli, co-author and Science Leader of Geology and Geophysics at BAS, notes the differences unveiled by the maps in a statement.
“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 160 million years ago.”
The blue regions indicate 'bowl' features, while the red indicates 'dome' features. West Antarctica actually has a thinner crust than East Antarctica, which has features like mountainous crumples (called orogen) and ancient, stable zones (called cratons).
The ESA explains that East Antarctica’s collection of “old cratons separated by younger orogens,” knits together a few regions, including an area that shows similarity to regions of southern Australia and India before the ancient supercontinent, Gondwana, broke apart 180 million years ago.
Apart from enhancing ancient history, understanding the deep structure of Antarctica may allow researchers to better understand the behavior of the shrinking ice sheets and glaciers that lie above.
Although Antarctica still holds its place to researchers as most mysterious modern continent, these new maps show just how much more there is to learn, beneath the ice.
