Human footprints found in an ancient lakebed in White Sands National Park, New Mexico date to between 21,000 years and 23,000 years ago, according to new findings that bolster a much-debated study from 2021.
The lightning-rod paper ran counter to the generally held scientific position that humans didn’t arrive in the Americas until between 13,000 years and 16,000 years ago. Prior to that – during the Last Glacial Maximum – massive glaciers would have impeded human migration from modern-day Siberia.
Scientists questioned the radiocarbon dating used in the 2021 study, which relied on seeds from an underwater grass plant called Ruppia cirrhosa. Spread throughout layers of sand and clay, the seeds served as markers from different time periods, the paper argued. But critics warned that the parent plants could have absorbed different carbon-14 from the water and produced results that skewed far too old.
