A longer record of life at White Sands
Human footprints preserved at White Sands National Park in New Mexico have already reshaped debate over the first people in the Americas. New research now adds a different dimension to the site: it reconstructs the changing environment experienced by the people who crossed the margins of ancient Lake Otero during the height of the last ice age.
The expanded excavations identify 20 distinct sediment horizons containing human footprints. Together, the layers span roughly 1,800 years, from about 23,500 to 21,700 years ago. That places repeated human activity at White Sands firmly within the last glacial maximum, the coldest phase of the most recent ice age.
The chronology matters because the original 2021 White Sands dates placed people in North America thousands of years earlier than many previously accepted sites. Those findings drew controversy. The researchers say subsequent work using several independent dating approaches strengthened the timing. The latest work shifts attention from the question of when people were there to the conditions they encountered while they were there.
Footprints are part of a wider environmental archive
The tracks are not isolated impressions in a single mudflat. They occur in sediments that also preserve clues to the plants, temperatures and rainfall patterns around the basin. Pollen records the vegetation present near the lake. Organic molecules in the sediments, including waxes originally produced by plant leaves, offer additional evidence about temperature and precipitation.
By combining those records, the team reconstructed a landscape that changed substantially over the period represented by the footprints. At the beginning of the sequence, Lake Otero covered much of the basin. Conifer forests grew in the surrounding mountains, and average annual temperatures were estimated to be about 4 degrees Celsius below modern levels.
That initial snapshot should not be treated as a stable Ice Age backdrop. The central finding of the new work is that conditions shifted rapidly. The sedimentary and environmental record points to a dynamic setting, with changes occurring while people continued to visit or move through the lake-margin landscape across many generations.
Why climate context changes the archaeological story
Archaeological discussions of early settlement often focus on routes, dates and the physical evidence that establishes human presence. White Sands supplies unusually direct evidence of people themselves: their footprints. The new study adds a long-running environmental record beside those tracks, allowing researchers to consider the challenges of living in a changing landscape rather than simply locating a site on a map of the past.
Repeated footprint-bearing horizons suggest that the basin remained important over an extended interval, even as local conditions evolved. The research does not turn the tracks into a complete account of daily life, but it provides a clearer setting for interpreting them. People were navigating the edges of a large lake in a period of colder-than-modern conditions and rapid climatic variability.
That perspective also makes White Sands valuable beyond the long-running question of the earliest arrival in the Americas. It preserves a rare combination of human traces and environmental indicators in the same sequence of deposits. Instead of inferring climate from a distant regional record, researchers can compare evidence of landscape change with repeated evidence of human activity at the site itself.
A record still being refined
The study’s conclusions rest on expanded excavation and on multiple types of evidence rather than the footprints alone. The researchers describe their work as published in Science Advances and Fossil Studies, and emphasize that the environmental reconstruction draws from pollen and molecular signals preserved in the sediments.
White Sands therefore remains a site where the scientific questions are broadening. The early dates have prompted reassessment of assumptions about the peopling of the Americas. The newer work asks how people persisted in a region undergoing substantial environmental change during the last ice age.
The answer, based on the current record, is not a simple story of a single brief visit. Twenty footprint horizons spread across nearly two millennia indicate a more sustained human presence in and around the ancient basin. As excavations and environmental analyses continue, the site may further clarify how Ice Age populations responded to a landscape that was colder, wetter in some respects, and far less climatically settled than the modern desert of southern New Mexico.
This article is based on reporting by Phys.org. Read the original article.
Originally published on phys.org
