Continental Drift, Hollywood Style

I’m psyched for any movie that dares to feature geological terminology in the title. So, you can bet I dragged my family to see "Ice Age: Continental Drift" as soon as it opened (two weeks later here in China than back home in the U.S.).

In animated films, perhaps even more so than live action, I am fully prepared for science to be sold out for a song. That’s why I was so pleased to note a few geologic details the moviemakers clearly made a point to get right.

Released ten years after the original, this fourth installment continues the adventures of three protagonist pals from the Pleistocene—mammoth Manny, sloth Sid and saber-toothed cat Diego. The trio gets separated from their herd and Manny’s family when the supercontinent Pangea splits apart into today’s familiar landmasses.

Okay, put aside for a moment your smug knowledge that Pangea, the most recent of Earth’s great supercontinents, first started breaking up 175 million years ago (a good long while before mammoths evolved) and that tectonic plates drift no more than a few millimeters a year. The key point here is that Hollywood actually played off the idea of a supercontinent! It even looked vaguely like Pangea. That’s a start.

Let’s look instead at this movie’s opening and closing scenes from the viewpoint of another recurring character, a saber-toothed squirrel named Scrat (while we also overlook the fact that no such creature ever existed, at least not during the ice age.)

Scrat starts the show with his precious acorn in hand (the same acorn he has pursued relentlessly for all four movies). Delicately, he places the nut on the icy ground, only to have the impact trigger a hairline crack in the ice that, after a slight dramatic pause, branches into dozens, hundreds more. In a matter of seconds, the cracks penetrate the bedrock below and the supercontinent on which he stands is torn asunder.

Like a legitimate time-lapse animation of plate tectonics at work, the animated continents rift apart and move to their current locations at top speed. During close-ups of the cracks unzipping, I couldn’t help feel a jolt of joy: The moviemakers depicted the cracks spreading across not only the land but the seafloor as well—presumably to avoid promoting the all-too common misconception that continents float across seawater the way icebergs do. Woo-hoo for myth-busting!

The movie ends with Scrat’s greed inciting yet another geological calamity, one far more esoteric than the break-up of a supercontinent. Once again he grabs a giant acorn. This one happens to be plugging a hole on a floating island (don’t ask), so his impulse results in the island sinking to the bottom of the ocean. An enormous volume of seawater somehow drains out of that same hole (you just have to see it for yourself), leaving Scrat dry and parched in a desert I took to be Death Valley.

Read more at Discovery News