Shrinking ice moving the Earth’s crust upwards in the Northern Antarctic Peninsula
As per scientists, earth’s mantle under Antarctica is moving rapidly, changing the shape of the land at a rate that can be recorded by GPS. Researchers have explained for the first time why the upward motion of Earth’s crust in the Northern Antarctic Peninsula is currently occurring so rapidly.
At the surface, Antarctica is a motionless and frozen landscape. Yet hundreds of miles down the Earth is moving at a rapid rate.
Earlier studies have found that the Earth is ‘rebounding’ due to the overlying ice sheet shrinking in response to climate change. This movement of the land was understood to be due to an instantaneous, elastic response followed by a very slow uplift over thousands of years. But Global Positioning System (GPS) data has shown that the land in this region is actually rising at a phenomenal rate of 15mm a year – much greater than what can be accounted for by the present-day elastic response alone. And scientists have shown for the first time how the mantle below the Earth’s crust in the Antarctic Peninsula is flowing much faster than expected, probably due to subtle changes in temperature or chemical composition. This shows that the mantle can flow more easily and therefore responds much more rapidly to the reduction of load hundreds of kilometers above it, changing the shape of the land. So as the glaciers slenderize and the load in that localized area decreases, the mantle pushes up the crust.
Since 1995, several ice shelves in the Northern Antarctic Peninsula have melted and caused ice-mass unloading, leading to the solid Earth to ‘bounce back’. The ice puts downward pressure on the Earth and as this weight reduces the crust bounces back.
Tags: Current Affairs 2014