BBC: Earliest definitive evidence of people in Americas
Humans reached the Americas at least 7,000 years earlier than previously thought, according to new findings.
Now, a team working in New Mexico has found scores of human footprints dated to between 23,000 and 21,000 years old. The discovery could transform views about when the continent was settled. It suggests there could have been great migrations that we know nothing about. And it raises the possibility that these earlier populations could have gone extinct.
The footprints were formed in soft mud on the margins of a shallow lake which now forms part of Alkali Flat in White Sands.
A team from the US Geological Survey carried out radiocarbon dating on seeds found in sediment layers above and below where the footprints were found. This gave the researchers remarkably precise dates for the impressions themselves.
Humans reached the Americas at least 7,000 years earlier than previously thought, according to new findings.
Now, a team working in New Mexico has found scores of human footprints dated to between 23,000 and 21,000 years old. The discovery could transform views about when the continent was settled. It suggests there could have been great migrations that we know nothing about. And it raises the possibility that these earlier populations could have gone extinct.
The footprints were formed in soft mud on the margins of a shallow lake which now forms part of Alkali Flat in White Sands.
A team from the US Geological Survey carried out radiocarbon dating on seeds found in sediment layers above and below where the footprints were found. This gave the researchers remarkably precise dates for the impressions themselves.