Washington, Dec. 12: Since West Antarctica is losing billions of tons of ice per year, its softer mantle rock is being nudged westward by the harder mantle beneath East Antarctica.
The discovery comes from researchers led by The Ohio State University, who recorded GPS measurements that show West Antarctic bedrock is being pushed sideways at rates up to about twelve millimeters-about half an inch-per year.
Terry Wilson, professor of earth sciences at Ohio State, and her team have been using GPS to observe vertical motion on the continent since the 1990′s.
She said that they were surprised to find the bedrock moving towards regions of greatest ice loss.
Wilson asserted that from computer models, they knew that the bedrock should rebound as the weight of ice on top of it goes away but the rock should spread out from the site where the ice used to be. Instead, they saw movement toward places where there was the most ice loss.
The seismic sensors explained why. By timing how fast seismic waves pass through the earth under Antarctica, the researchers were able to determine that the mantle regions beneath east and west are very different. West Antarctica contains warmer, softer rock, and East Antarctica has colder, harder rock.
Wilson said that such extreme differences in mantle properties are not seen elsewhere on the planet where glacial rebound is occurring. (ANI)