The paper is the first to show the current fast uplift of the Icelandic crust is a result of accelerated melting of the island’s glaciers and coincides with the onset of warming that began about 30 years ago, the scientists said.
Some sites in south-central Iceland are moving upward as much as 1.4 inches per year — a speed that surprised the researchers. "Our research makes the connection between recent accelerated uplift and the accelerated melting of the Icelandic ice caps," said first author Kathleen Compton, a UA geosciences doctoral candidate.
Geologists have long known that as glaciers melt and become lighter, the Earth rebounds as the weight of the ice decreases. Whether the current rebound geologists detect is related to past deglaciation or modern ice loss has been an open question until now, said co-author Richard Bennett, a UA associate professor of geosciences. "Iceland is the first place we can say accelerated uplift means accelerated ice mass loss," Bennett said.
To figure out how fast the crust was moving upward, the team used a network of 62 global positioning satellite receivers fastened to rocks throughout Iceland. By tracking the position of the GPS receivers year after year, the scientists "watch" the rocks move and can calculate how far they have traveled — a technique called geodesy.
The new work shows that, at least for Iceland, the land’s current accelerating uplift is directly related to the thinning of glaciers and to global warming. "What we’re observing is a climatically induced change in the Earth’s surface," Bennett said....