Deep inside the Greenland ice sheet, radar images have revealed strange, plume-like structures distorting the layering deposited over eons.<\/p>\n
Now, more than a decade after their discovery<\/a>, scientists think they have figured out what causes these structures, and it’s a real hum-dinger. According to modeling, the plumes are a striking match for convection: the roiling upward transport of heat more commonly linked to the fiery, molten rock churning<\/a> beneath Earth’s crust.<\/p>\n “Finding that thermal convection can happen within an ice sheet goes slightly against our intuition and expectations. Ice is at least a million times softer than the Earth’s mantle, though, so the physics just work out,” says glaciologist Robert Law<\/a> of the University of Bergen in Norway.<\/p>\n “It’s like an exciting freak of nature.”<\/p>\n The Greenland ice sheet, which covers 80 percent of the island, is one of our planet’s biggest reservoirs of frozen water, and is forecast to play a major role in rising sea levels as it melts into the ocean<\/a>. Understanding the physics inside it is vital for predicting how the ice sheet will change over time.<\/p>\n This is why scientists use ice-penetrating radar. Radio waves pass through the ice and reflect back differently as they encounter internal layers \u2013 snow that fell long ago and was compacted into ice as more snow piled on top. Each of these layers has its own characteristics \u2013 slightly different acidity levels, for example, and variations in dust, ash, and chemical content.<\/p>\n In a 2014 paper<\/a>, scientists described strange structures these radar images had revealed deep inside the ice in northern Greenland. These large, upward-buckling features were unrelated to the topography of the bedrock below, presenting a puzzle<\/a> researchers have been trying to solve ever since<\/a>.<\/p>\n![\"YouTube](\"https:\/\/img.youtube.com\/vi\/-JdzA6fC91s\/0.jpg\")