Asia and Americas on Course for Arctic Collision
- 4:06 PM
- Categories: Earth Science
It’ll be a geological showdown for the ages, with North America, South America, Europe and Asia colliding head-on over the North Pole to create a supercontinent called Amasia.
Unfortunately, nobody we know will be around to watch the collision, which won’t happen for another 50 million years or more. But it’s still fun to imagine.
“The snapshot that is the present is smack-dab in the middle of what we call the supercontinent cycles,” said geologist Ross Mitchell of Yale University, lead author of a Feb. 8 Nature prediction of supercontinental trajectories. “We’re part of something larger, both in the past and into the future.”
Mitchell’s group isn’t the first to say that Amasia will form, but geologists differ on where exactly this will happen.
Some think that supercontinents break up, drift apart, and gather again in the same place. They say Amasia will swallow the Atlantic and center itself over present-day Africa, at the heart of Pangea, the last supercontinent, which broke up 250 million years ago.
Other geologists believe supercontinents break up, drift apart, and gather again on the other side of Earth. This would place Amasia somewhere between Hawaii and Fiji, and swallow the Pacific.
Mitchell’s group, however, places Amasia in the Arctic. Their conclusion is based on records of Earth’s magnetic field as contained in rocks dating back 800 million years to Rodinia, the supercontinent that preceded Pangea.
According to their interpretation, the geomagnetic record only makes sense if supercontinents rotate on their axes at a 90 degree angle, which would send Amasia into an unexpected polar location.
Given that their data spans 800 million years yet contains only 2 examples of supercontinental rotation, this will be a hard hypothesis to test. Whether or not it holds up, however, the research should illuminate a question even more fundamental than where supercontinents will gather.
“One of the larger questions in research is, ‘Why does a supercontinent even break apart?’” said Mitchell.
Image: At left, the current arrangement of the continents; at right, their proposed arrangement in 100 million years. (Mitchell et al./Nature) Video: The last 500 million years of Earth’s continental drift. (Mitchell et al./Nature)
Citation: “Supercontinent cycles and the calculation of absolute palaeolongitude in deep time.” By Ross N. Mitchell, Taylor M. Kilian & David A. D. Evans. Nature, Vol. 482, No. 7384, 9 February 2012.