A map of gravity reveals the tectonic secrets under the ice of Antarctica | Smart News

Geologists have pretty well reconstructed the history of plate tectonics, or how parts of the earth's crust have crashed around the world, breaking apart and separating. But there remains a big problem to solve: Antarctica. This is because the continent is covered by a layer of ice with an average thickness of 2.5 km, which means that it is almost impossible to directly study the bedrock. But recently, a satellite measuring the gravitational pull of gravity has been able to penetrate this ice, reports Hannah Osborne Newsweek revealing the tectonic history locked up under the frozen continent.

The data comes from the European Space Agency's GOCE (Exploration of the gravity and circulation of the oceans) satellite, which orbited around the Earth between 2009 and 2013. During its mission, the aircraft collected accurate measurements of Earth's gravity, revealing the thickness and density of the planet's lithosphere. , a combo of the crust and the upper mantle. During the last year of his mission, while he was running out of fuel, the operators dropped the satellite just 158 ​​miles above the ground to get even better readings before GOCE did be exhausted.

Since then, researchers have converted these data into highly accurate 3D maps of the lithosphere. An exciting discovery, published in the journal Scientific reports, is that the crust of eastern and western Antarctica are very different, suggesting that the two halves of the continent have a divergent history.

"These gravimetric images are revolutionizing our ability to study the least understood continent on the planet, Antarctica," explains British Antarctic Survey geophysicist Fausto Ferraccioli, co-author of the paper.

In particular, the data show that the crust of West Antarctica is thinner than that of eastern Antarctica, composed of a patchwork of old cratons or stable crustal pieces forming the core of the continents held together by young orogens. mountain belts. The more complex seems to be intimately related to the bursting of the supercontinent Gondwanalet 160 million years ago.

"The new images show us the fundamental difference of the lithosphere under eastern and western Antarctic, consistent with previous seismic discoveries," Ferraccioli tells Osborne. "In the interior of East Antarctic we have also found a higher degree of complexity than the current seismic views, suggesting that this part of the continent is a mosaic of ancient cratons and d & # 39; orogenic. Some of these areas have obvious links with formerly adjacent continents of the Gondwana supercontinent, such as Australia, India and Africa. "

The new maps will help researchers understand how old pieces of continents fit together and evolve over time. But the cards have more than a historical interest. Knowing what lies beneath the ice cap will help scientists understand its behavior and determine how the bedrock will react when climate change begins to melt the ice, causing the rock to rebound.

The gravity map is not the only recent study revealing frozen southern geology. Another map made by the British Antarctic Survey and its collaborators in July combined 50 years of data on magnetic anomalies collected across the continent. These data help researchers create detailed maps of subglacial mountain ranges and other entities trapped beneath the ice sheet. Together, these studies and others are beginning to give us our first real vision of a continent hidden from view.

Like this article?
S & # 39; REGISTER for our newsletter