New research suggests Antarctic bedrock is shifting towards the areas that are rapidly losing ice.
West Antarctica is losing billions of tons of ice every year and the soft mantle rock in the region is being "nudged westward" by the hard mantle beneath East Antarctica, an Ohio State University news release reported.
The research team used GPS measurements to show West Antarctic bedrock is moving sideways by as much as half an inch (about twelve millimeters) every year."
The team was surprised to make this conclusion because the movement is opposite to what they expected. They found the bedrock was moving towards areas where ice had recently melted.
"Just like taking the bowling ball off the mattress, removing ice from the Earth's crust causes it to rebound, creating [motion] up and away from where the ice used to be. So we were expecting to see horizontal motion away from regions where there used to be lots of ice in the past. However, in some places we instead saw horizontal motions towards the regions where former ice existed. This is opposite to what we would expect," Stephanie Konfal, a research associate with POLENET, said in an e-mail to Headlines and Global News.
Konfal compared the mechanism behind the phenomenon to a pot of honey. In this example some parts of the honey are soft while others are relatively hard. If one were to push a spoon down on the honey some will move away in a non-uniform pattern. "The hard spots will push into the soft spots," and when the spoon is removed the honey won't uniformly move back in and fill in the gap because it will still be blocked by hard areas.
This is how the soft mantle interacts with the harder mantle under the Antarctic freeze, the researchers said motions resulting from such differences in the Earth's mantle had not been observed anywhere else on Earth.
There are no known reprecussions from the shift in bedrock.
"There are no direct environmental consequences from the bedrock movement we observe in Antarctica. But our observations are significant for the environment because they help us understand ice mass change, which does impact the environment...by studying how the bedrock moves, we can study how the ice is changing," Konfal told HNGN.
The team plans to continue their study.
"We have field team members deploying to Antarctica right at this very moment, to install additional GPS stations that will help us further constrain how the bedrock is moving in Antarctica in response to ice mass change. The ultimate goal is to improve computer models that look at ice mass change, and that is exactly what our GPS data can do, Konfal told HNGN.