Earth’s Crust under Antarctica is Moving Faster than Previously Believed, Study


The upward motion of the Earth's crust in the Northern Antarctic Peninsula was studied by researchers at the Newcastle University who stated that it is moving faster than previously believed.

Rising temperature globally led to the melting of several ice shelves in Antarctica since 1995. As a result, the ice sheets covering the land lost a significant amount of ice mass, triggering the "rebounding" of the Earth's crust.

The movement of the earth's crust was understood to be an instantaneous, elastic response and was estimated to occur over a period of thousand years.

"Think of it a bit like a stretched piece of elastic," said Grace Nield, the study's lead researcher, in a statement.  "The ice is pressing down on the Earth and as this weight reduces, the crust bounces back."

But, the GPS data collected by the researchers showed that the ground is moving upward faster than previously believed. The findings indicate that the movement of the land in this region is shifting skyward at an extraordinary rate of 15mm per year.

"You would expect this rebound to happen over thousands of years and instead we have been able to measure it in just over a decade," added Nield. "Because the mantle is 'runnier' below the Northern Antarctic Peninsula, it responds more quickly to what's happening on the surface. So, as the glaciers thin and the load in that localised area reduces - the mantle pushes up the crust."

Using seven different GPS stations throughout the Northern Peninsula of Antarctica, the researchers have also found that the mantle below the Earth's crust in the Antarctic Peninsula is flowing faster than usual due to slight temperature change or chemical composition. The mantle's quick response to the surface alterations is changing the shape of the land.

In the study, the researchers collected data concerning the vertical deformation of the crust. Further, studies will focus on the horizontal motion of the ground beneath the Antarctica. Data on both, horizontal and vertical, deformations will help scientists understand the phenomenon in three dimensional aspects.

"Seeing this sort of deformation of the Earth, at such a rate, is unprecedented in Antarctica," said Peter Clarke, Newcastle University Geophysical Geodesy professor. "What is particularly interesting here is that we can actually see the impact that glacier thinning is having on the rocks 250 miles down."

The team published its findings in the online journal Earth and Planetary Science Letters.

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