Study Bolsters Theory of Heat Source Under West Antarctica
Illustration of flowing water under the Antarctic ice sheet. Blue dots indicate lakes, lines show rivers. Marie Byrd Land is part of the bulging “elbow” leading to the Antarctic Peninsula, left center. Credits: NSF/Zina Deretsky
A new NASA study adds evidence that a geothermal heat source called a mantle plume lies deep below Antarctica’s Marie Byrd Land, explaining some of the melting that creates lakes and rivers under the ice sheet. Although the heat source isn’t a new or increasing threat to the West Antarctic ice sheet, it may help explain why the ice sheet collapsed rapidly in an earlier era of rapid climate change, and why it is so unstable today.
The stability of an ice sheet is closely related to how much water lubricates it from below, allowing glaciers to slide more easily. Understanding the sources and future of the meltwater under West Antarctica is important for estimating the rate at which ice may be lost to the ocean in the future.
Antarctic “hot spots”
Antarctica’s bedrock is laced with rivers and lakes, the largest of which is the size of Lake Erie. Many lakes fill and drain rapidly, forcing the ice surface thousands of feet above them to rise and fall by as much as 20 feet (6 meters). The motion allows scientists to estimate where and how much water must exist at the base.
