Dozens of awe-inspiring ancient footprints left on the shores of an ice age lake have reignited a long-running debate about when the first people arrived in the Americas.
Two years ago, a team of scientists came to the conclusion that human tracks sunk into the mud in White Sands National Park in New Mexico were more than 21,000 years old. The provocative finding threatened the dominant thinking on when and how people migrated into the Americas. Soon afterward, a technical debate erupted about the method used to estimate the age of the tracks, which relied on an analysis of plant seeds embedded with the footprints.
Now, a study published in the journal Science confirms the initial finding with two new lines of evidence: thousands of grains of pollen and an analysis of quartz crystals in the sediments.
“It’s more or less a master class in how you do this,” said Edward Jolie, an anthropological archaeologist at the University of Arizona who has studied the White Sands footprints in the field but was not involved in the new study. “As Carl Sagan said, ‘Extraordinary claims require extraordinary evidence.’ They have some extraordinary evidence.”
Lorena Becerra-Valdivia, a fellow at the Oxford Radiocarbon Accelerator Unit, said that the results support her modeling work, which suggested that people first crossed into present-day North America before 29,000 years ago, possibly traveling via the ocean.
“If anything, early findings like the White Sands footprints should inspire further scientific investigation in what is a dynamic and changing field,” Becerra-Valdivia said.
Some critics who raised concerns about the initial study said that they were encouraged by the follow-up analyses but remained unconvinced.
“I don’t agree that it resolved the issue of the timing, but they have made progress,” said Loren Davis, an anthropologist at Oregon State University. “Knowing the age of this is important, because if these researchers are correct and people are truly in New Mexico at 23,000 years ago, or even 21,000 years ago, it means we have to change our fundamental understanding of some things.”
A snapshot of life in the Pleistocene
Fossil footprints were first seen in New Mexico’s Tularosa Basin in the early 1930s and were initially thought to be evidence of a bigfoot, said David F. Bustos, a resource program manager at White Sands National Park. They turned….