Traditionally, paleoanthropologists believed that humans arrived in North America around 16,000 to 13,000 years ago. Recently, however, evidence has accumulated supporting a much earlier date. In 2021, fossilized footprints from White Sands National Park in New Mexico, the United States, were dated to between 21,000 and 23,000 years ago, providing key evidence for earlier occupation, although this finding was controversial. In a new study, Dr. Jeffery Pigati of U.S. Geological Survey and colleagues returned to the White Sands footprints and obtained new dates from multiple, highly reliable sources; they, too, resolved dates of 20,000 to 23,000 years ago.
When and how humans first migrated into North America has long been debated and remains poorly understood.
Current estimates for the timing of these first occupants range from about 13,000 years ago to more than 20,000 years ago.
However, the earliest archaeological evidence for the region’s settlement is sparse and often controversial.
In September 2021, paleoanthropologists reported the discovery of human footprints preserved in an ancient lakebed dating to between 23,000 and 21,000 years ago in what is now White Sands National Park, New Mexico, the United States.
Their results began a global conversation that sparked public imagination and incited dissenting commentary throughout the scientific community as to the accuracy of the ages.
“The immediate reaction in some circles of the archeological community was that the accuracy of our dating was insufficient to make the extraordinary claim that humans were present in North America during the Last Glacial Maximum,” Dr. Pigati said.
The controversy centered on the accuracy of the original ages, which were obtained by radiocarbon dating.
The age of the White Sands footprints was initially determined by dating seeds of the common aquatic plant Ruppia cirrhosa that were found in the fossilized impressions.
But aquatic plants can acquire carbon from…
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