A joint team of American researchers has contradicted previous claims that fossilized footprints found in 2009 in the Otero Lake basin in New Mexico’s White Sands National Park are the oldest in North America, presumably from the last ice age. The group’s latest work appeared in a recent edition of Quaternary Research.
Last September, researchers at the US Geological Survey did radiocarbon dating Cirrhous rupee seeds deposited in all footprints. Their findings implied that the footprints were left between 22,800 and 21,130 years ago. Previously, the earliest known humans in North America dated to between 14,000 and 16,000 years ago. If true, the conclusion would overturn all sorts of assumptions in the field.
The team published its findings in Science last year. “This is a bombshell,” noted Ruth Gruhn, an academic archaeologist not involved in the study. “It’s very difficult to refute.”
Charles Oviatt, a Kansas State University geologist who helped refute those claims, said Heritage newspaper this week who read the original Science article, “and was initially struck, not just by how awful the footprints alone were, but by how important accurate dating would be.”
Last year, researchers recognized the potential for interference from the “reservoir effect.” Underwater plants like Cirrhous rupeean underwater trench grass, can look much older as they photosynthesize from water, which often contains ancient carbon, rather than in the atmosphere, which would create a more contemporary image.
Oviatt joined three colleagues from DRI, the University of Nevada and Oregon State University to set up the test Cirrhous rupee specimens archived at the University of New Mexico herbarium. They were originally collected while alive from a pond fed by a nearby spring during 1947.
Leading commercial radiocarbon laboratory Beta Analytic conducted dating on those archived samples. The findings dated the plants at 7,400 years old, “an offset from the plant’s use of ancient groundwater.” Heritage newspaper noticed. If these findings have been skewed by 7,400 years, then there’s a chance that the footprints at White Sands actually line up with existing records.
“While researchers acknowledge the problem, they underestimate the basic biology of the plant,” Rhode said. “For the most part it uses the carbon it finds in the lake waters. And in most cases, that means it’s taking in carbon from sources other than the contemporary atmosphere, sources that are usually quite old.
It’s just the scientific method at work. “The original investigators have gone to great lengths to confirm their claims and I’m told they are still working on them,” Rhode told Artnet News. “They have publicly acknowledged the need for such corroborating evidence to convince the community at large. There is now and will continue to be a lot more work on this.”
Follow Artnet news on Facebook:
Want to keep up with the art world? Sign up for our newsletter to get the latest news, eye-opening interviews and incisive critical interpretations that propel the conversation forward.