Did Clovis use ice-free corridor?
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The new research, released Wednesday by the journal Nature, casts further doubt on the inland corridor.
This February 2012 provided by researcher Mikkel Winther Pedersen shows a southward view down Cline River in Alberta, Canada, where retreating ice sheets created an ice-free corridor more than 13,000 years ago. According to a theory, the ancient humans passed from the Bering land bridge, and then waited for ice sheets of today’s Canada to move towards south.
The broad strokes haven’t changed. So the people hunkered down in that small Alaska region, called Beringia, for thousands of years.
It’s always been thought that the first people to populate America thousands of years ago migrated southwards through a frosty corridor in what is now called Canada.
That idea ran into a problem as archaeologists documented human presence in the Americas at earlier and earlier times. “Whether you believe these people were Clovis, or someone else, they simply could not have come through the corridor, as long claimed”, Willerslev added.
As per the researchers, the ice-free corridor would have formed 14,000 years back. But, as the authors of the study explain, this corridor did not become passable until long after the Clovis people had reached south of the glacier wall.
But just because there wasn’t an ice sheet in their way anymore, doesn’t mean that people could have migrated down the approximately 930-mile-long corridor.
The study’s global team of researchers travelled in the dead of winter to the Peace River basin in western Canada, a spot that based on geological evidence was among the last segments along the 1,000-mile corridor to become free of ice and passable.
Plants and animals would have to be thriving along the whole corridor to provide inviting food sources, wood for fire, and other survival needs. “When could they actually have survived the long and hard journey through it?” They also studied a “bottleneck” region in the ancient corridor.
“It’s 1,500 kilometres. You can’t pack a lunch and do it in a day”, said Meltzer.
An worldwide team of researchers extracted ancient plant and animal DNA from lake sediment cores in the region that was once covered in glaciers, and found, through a process known as “shotgun DNA sequencing” that before roughly 12,600 years ago, there were no plants or animals in the area. They focused on a section of the corridor that was one of the last to become ice-free and dug into lakebed sediments for clues as to what once lived there.
Clovis people are believed to arrive in America about 13,000 years ago, making it impossible for them to pass through the ice-free corridor that was not viable for life until 12,600 years ago.
Their research, based on plant remains and environmental DNA, reveals the landscape couldn’t support human life until about 2,000 years after the first humans were recorded in North America.
At the end of the most recent ice age, when the first North Americans arrived, the northwestern section of the continent was still covered in two vast ice sheets.
And “both papers are in agreement” as to the significance of the ice-free corridor for human migration, he says.
“The bottom line is that even though the physical corridor was open by 13,000 years ago, it was several hundred years before it was possible to use it”, Willerslev says.
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However it is still not known whether the Clovis descended from those that came down the Pacific coast. The researchers found evidence, starting about 12,600 to 12,500 years ago, of mammoth and bison; then voles and jackrabbits; and after that, bald eagles, elk, and moose roamed the landscape, their data demonstrated.
