Abstract:
It is commonly believed the oldest known humans in North America lived around 12,000 years ago from a site in Clovis, New Mexico. But in 2017, the National Park Service and a team of researchers found fossil prints of megafauna that were contemporaneous with human prints. Since 2014 thousands of human and megafauna fossil prints of Mammoth, Giant Ground Sloth, Saber tooth cat and many other megafauna have been found across 80,000 acres within the park. ​In 2020,​ 61 human footprints were discovered that dated over ten millennia older than Clovis people [Bennet et al.,Science, 373 (6562),Nature News, 2021]. The footprints are preserved in layers of gypsum soil in the White Sands National Park, NM, beneath some newer fossils of megafauna like mammoth. This finding fundamentally changes the timeline on North American human habitation – turning back the clock of human arrival in the Americas many thousands of years.

Archaeologists and researchers in allied fields have long sought to understand human colonization of North America. Questions remain about when and how people migrated, where they originated, and how their arrival affected the established fauna and landscape. In this keynote lecture, Resource Program Manager David Bustos will present evidence from the stories seen in the prints and excavated surfaces in White Sands National Park, where multiple in situ human and megafauna footprints are stratigraphically constrained together and bracketed by 11 seed layers that yield calibrated radiocarbon ages between ~23 and 21 thousand years ago. These findings confirm the presence of humans in North America during the Last Glacial Maximum, adding evidence to the antiquity of human colonization of the Americas and providing a temporal range extension for the coexistence of early inhabitants and Pleistocene megafauna.

The oldest known humans in North America lived around 12,000 yeast ago in Clovis, New Mexico. But in 2017, National Park Service Archaeologist David Bustos discovered 61 human footprints that dated over ten millennia older than Clovis humans [Bennet et al., Science, 373 (6562), Nature News, 2021]. The footprints are preserved in layers of gypsum soil in the White Sands National Park, NM, beneath some newer fossils of megafauna like mammoth. This finding fundamentally changes the timeline on North American human habitation – turning back the clock of human arrival in the Americas many thousands of years.

The creation and preservation of these new discoveries were made possible by an abrupt climatic event [Pigati et al., 2022, 72nd Annual Rocky Mountain Section Meeting]. During the late Pleistocene, full glacial conditions were interrupted repeatedly by abrupt warming events called Dansgaard-Oeschger, or D-O events. In the southwestern U.S., D-O events caused centuries-long megadroughts, which devastated spring ecosystems, lowered lake levels, affected sea-surface temperatures and ocean circulation patterns, and even triggered seismic activity. In the Tularosa Basin (where White Sands is), lake levels dropped dramatically during D-O 2 at ~23,500 years ago, exposing an expansive lake margin. Humans and megafauna then walked across the patchwork of wet and dry ground, leaving behind footprints and trackways that were preserved in multiple sediment layers over the course of time.

Speaker Bio:
David Bustos is a wildlife biologist and resource program manager at White Sands National Park. He is a graduate of New Mexico State University. He is responsible for the management of the park’s cultural and natural resources and has investigated ancient human and megafauna for nearly two decades.