Here鈥檚 what you鈥檒l learn when you read this story:Researchers determined that footprints in White Sands National Park in New Mexico are from the oldest migrants to North America.The footprints first made headlines after a study published in 2021 claimed that they were thousands of years older than the Clovis people of New Mexico, who had long been thought to be the first North American culture.Who these nomadic people were鈥攐r whether they stayed in New Mexico or moved on鈥攊s still unknown.An endless ocean of white sprawling across New Mexico鈥檚 Tularosa Basin, White Sands National Park glitters with dunes of gypsum sand. From those sands have surfaced footprints that would rewrite human history. Found in ancient clay that had long since hardened to stone, the footprints were thought to be anywhere from 21,000 to 23,000 years old. Controversy surrounded the finding鈥攊f these tracks really were that ancient, it would mean that they were even older than the Clovis people from the late Pleistocene, whose name comes from a site in New Mexico that was thought to be the oldest known settlement in North America. Whether or not these tracks really did predate the Clovis culture would be debated for years until the investigation was reopened.Archaeologist and geologist Vance Holliday鈥攏ow a professor emeritus at the University of Arizona鈥攕tarted researching the geologic strata of White Sands in 2012. In 2019, researchers from Bournemouth University in the UK teamed up with the U.S. National Park Service for the excavation that resulted in the discovery of the footprints, and some of Vance鈥檚 data on the ages of seeds and pollen in the area was used to date the prints for a study published in 2021. If the age of the footprints was correct, that would make them 10,000 years older than the Clovis people.With doubts surrounding that study, Vance became determined to prove their age, and finally succeeded by dating the mud rock they were imprinted on.鈥淭he issue of the arrival of the first Americans has long been contentious and the record from the White Sands locality generated considerable debate focused on the validity of the dating,鈥 he said in a new study recently published in the journal Science Advances. The age of the footprints coincides with the final phase of the Pleistocene epoch, otherwise known as the Last Glacial Maximum. Ice sheets that blocked the Bering Land Bridge between Asia and North America made human migration impossible. This could potentially mean that the first people to settle in North America crossed over before Earth plunged into a deep freeze鈥攁 time period which aligns with the age of the footprints, as confirmed by Vance. What is now the Tularosa Basin was once the bottom of a paleolake called Lake Otero that formed after the snow and ice melted. Flows of melted snow brought dissolved gypsum to Lake Otero, which emerged as an expanse of white sand when the lake evaporated into a dry playa. Erosion may have erased some of this history forever, but beneath the sand, fossils of megafauna like mammoths and ground sloths were still preserved鈥攁longside the controversial footprints.Whoever made these prints traveled through marshlands before Lake Otero formed and walked through gley鈥攎ud that is too waterlogged for oxygen to penetrate. Organisms in the mud instead turn to iron and manganese compounds in this mud to survive, chemically breaking down these compounds and turning the mud shades of blue, green, or gray. The gley was radiocarbon dated to anywhere between 20,700 and 22,400 years old, supporting previous findings that came close to that range. Before this, Vance had relied on pollen remnants and the seeds of the aquatic plant Ruppia cirrhosa (also known as spiral tasselweed or ditchgrass) to date the impressions.鈥淎t the time that the human tracks were created [鈥 there was an extensive body of standing but shallow water or wetlands in proximity to the trackways throughout the period of human activity,鈥 Vance said.If this is proof of what could be the first humans who migrated to the Americas, then why did they only leave footprints? The absence of artifacts might be explained by nomadic life. Vance thinks that one of the trackways was easily walked over in only seconds, and hunter-gatherers might have only been passing through the basin while holding onto tools and supplies that were not easily replaced. Who these enigmatic people were remains a mystery burried in the sands of time.