18 January 2013

Friday fold: “Chasing Ice”

Posted by Callan

A couple of weeks ago, we watched the new documentary film Chasing Ice, which documents James Balog’s efforts in the Extreme Ice Survey. Balog was a member of my cadre of Fine fellows, and so I’ve been fortunate enough to see him speak in person, passionately and lucidly, about his work documenting Earth’s melting glaciers. A month or so ago, shortly after the film was released, a clip from it was circulating on the Internet, showing the Greenland EIS team’s moments of watching (and filming) the largest glacial calving event ever recorded. Watch the video, if you haven’t already. While the spectacle of this event is at once stunning and alien (Oh, for a sense of scale!), my eye caught a lovely fold briefly exposed in the ice as a newly-minted berg bobs up and plunges back down into the fjord. I thought it would make a unique Friday fold…

Here’s a screen shot:

Red arrows show one kinematic solution for producing Z-folds like those. This folding would have occurred within the glacier, presumably in the ductile zone below the “zone of fracture”.

A cool Friday fold for you. You should watch the movie when you get a chance. It’s a superb portrait of a principled man driven to enter extremely risky situations for the sake of generating a blend of science and art that will be of use to humanity.