Moving Teardrop-Shaped Lakes Discovered on George VI Ice Shelf
03.02.2012 - Water & Oceans, Ice & Snow, Antarctic
Researhcers from the University of Chicago have been keeping an eye on teardrop-shaped lakes on top of the George VI Ice Shelf on the Antarctic Peninsula, which travel as much as 1.5 metres a day – but in a very unusual manner.
Compiling images from the last decade, glaciologist Dr. Doug MacAyeal and student researcher C.H. LaBarbera tracked travelling lakes in images taken between 2001 and 2010. The lakes form during the austral summer melt season and freeze over in winter, and are the result of strange weather patterns creates by mountains on Alexander Island, into and around which the ice shelf flows.
Dr. MacAyeal expected the lakes to move over time, yet he was struck by the manner in which they moved: the lakes buckle next to one another, similar to the way thick syrup buckles when pouring it, a phenomenon known as viscous buckling.
Unlike most of its ice shelf neighbours, which flow unobstructed into the sea, the George VI Ice Shelf runs into an island as it makes its way seaward. The ice shelf is at the confluence of a number of different glaciers flowing from Palmer Land on the peninsula. The ice pours off from the George VI Ice Shelf and oozes around Alexander Island. As the ice encircles the island, it brings the melt lakes along with it as it flows, which creates the viscous buckling phenomenon seen in the lakes.
While catastrophic ice shelf collapses have been witnessed on the Antarctic Peninsula, which has warmed 4 – 4.5°C over the past half century, and data show the ice shelf thinning and fracturing along its southern front, the George VI Ice Shelf is doing better than its ice shelf neighbours. Alexander Island insulates the ice shelf from a warming ocean and buttresses it, keeping its flow in check. However Dr. MacAyeal said scientists expect to see significant changes in the region in the next one or two decades.
Lake formation in ice shelves tend to be a precursor of ice shelf collapse; yet since the lakes on top of George VI Ice Shelf are caused by a phenomenon other than climate warming, studying the lakes offers an opportunity to study how lakes on ice shelves alter their structure and better understand the physics of ice shelves.
