Asian Turtles Moved Over the Pole to Get to America

Until this point in time researchers have believed that the Asian turtles that moved to America several millions of years ago did so by going around Alaska, and then spreading into the new land. However, recent discoveries, made by a team of investigators from the University of Rochester, seem to prove the fact that the Asian turtle actually reached the new land by swimming across a sea of freshwater that used to lie on top of the North Pole, which is now covered by ice. The former sea would rest atop the salty waters of the Arctic Ocean, and is believed to have been created by a massive influx of carbon dioxide, more than 90 million years ago.

"We've known there's been an interchange of animals between Asia and North America in the late Cretaceous period, but this is the first example we have of a fossil in the High Arctic region showing how this migration may have taken place. We're talking about extremely warm, ice-free conditions in the Arctic region, allowing migrations across the pole," University of Rochester professor of geophysics John Tarduno, who has also been the leader of the expedition in Arctic Canada, shares.

"We found this turtle right on top of the last flood basalts – a large stretch of lava from a series of giant volcanic eruptions. That leads us to believe that the warming may have been caused by volcanoes pumping tremendous amounts of carbon dioxide into the Earth's atmosphere. There's evidence that this volcanic activity happened all around the planet – not just the Arctic. If it all happened on a short enough timescale, it could cause a super-greenhouse effect," he adds.

The fossil that prompted the new find was dubbed Aurorachelys, or the aurora turtle, and was discovered in 2006, when Tarduno conducted his expedition in Northern Canada. Following careful studies, he and his team have concluded that there is no way for the turtle to have ended up at that location due to tectonic activities, and that the animal was a native of the area, which was considerably warmer at the time.

In addition, the team has determined that it's possible that the intense volcano activity at that time made possible the emergence of a number of small islands between Canada and Asia, and that the migrating turtles might have found refuge on them during their long migration. To support this theory, they argue that the Alpha Ridge, a portion of the Arctic ocean floor that is close to the surface, might have been, at the time, on the surface.