Ancient Footprints Push Back Human Arrival in North America

A groundbreaking scientific discovery in New Mexico has pushed back the timeline of human existence in North America, challenging prior beliefs. Fossilized footprints, first uncovered in the White Sands National Park in New Mexico and initially documented in September 2021, have been confirmed to be between 21,000 and 23,000 years old, which is significantly earlier than previously believed.

Before this revelation, it was widely accepted that humans first appeared in North America between 13,500 and 16,000 years ago. The idea that these footprints, some of which display distinct human features with five toes, could date back to 21,000 to 23,000 years ago raised questions about the accuracy of the initial findings.

In response to the doubts and skepticism surrounding the dating of these footprints, a team of researchers from the U.S. Geological Survey (USGS) and other scientists undertook a comprehensive follow-up study. They employed two novel approaches to ascertain the age of the prints, with the aim of bolstering the credibility of their findings.

Co-author of the new study, Jeff Pigati, a USGS research geologist, explained their motivation, stating, “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.” Pigati went on to highlight that their targeted methodology in this new research provided compelling results.

In their quest for greater accuracy, the scientists initially used radiocarbon dating on seeds from the Ruppia cirrhosa plant discovered in the fossilized footprints. However, because these plants are aquatic and can retain carbon from water rather than air, there was some uncertainty in the age estimates. To address this, the team conducted radiocarbon dating on conifer pollen, which is derived from terrestrial plants found in the same sediment layers as the seeds.

Co-author Kathleen Springer, a USGS research geologist, emphasized their commitment to validating their original findings, stating, “Even as the original work was being published, we were forging ahead to test our results with multiple lines of evidence. We were confident in our original ages, as well as the strong geologic, hydrologic, and stratigraphic evidence, but we knew that independent chronologic control was critical.”

The researchers painstakingly isolated and examined a remarkable 75,000 pollen grains from the same sediment layers and found that their age was statistically identical to the Ruppia cirrhosa seeds. To further corroborate their findings, they employed a different dating method, optically stimulated luminescence, on quartz grains discovered within the footprints, determining a minimum age of around 21,500 years. With three independent lines of evidence supporting the age range of 21,000 to 23,000 years, the USGS considers it highly unlikely that this dating is incorrect.

This remarkable discovery is not the first of its kind in the White Sands National Park. Previous findings have included human and sloth footprints, which were later dated to 18,000 years using ancient seeds found nearby. In 2018, footprints of a female and a toddler were unearthed, providing a fascinating glimpse into their daily life.

The ancient footprints found in New Mexico have not only rewritten history but also remind us of the incredible stories that can be uncovered by delving into the past, allowing us to gain a deeper understanding of human history on the North American continent.