A joint team of American researchers has contradicted previous claims that fossil footprints discovered in 2009 in the Lake Otero Basin in New Mexico’s White Sands National Park are the oldest in North America – dating back to the last Ice Age every mention. The group’s latest work appeared in a recent issue of Quaternary Research.
Last September, researchers from the United States Geological Survey radiocarbon dated cirrhosa rupee seeds given through the footprints. Their results suggested that the footprints were left between 22,800 and 21,130 years ago. Previously, the earliest known humans in North America were dated between 14,000 and 16,000 years ago. If true, the conclusion would defeat all kinds of assumptions in the field.
The team published its findings in Science last year. “This is a blow,” observed Ruth Gruhn, an academic archaeologist who was not involved in the study. “It’s very difficult to disprove.”
Charles Oviatt, a Kansas State University geologist who helped refute those claims, said Daily Heritage this week he read the original Science article, “and was initially struck, not only by how enormous the footprints were on their own, but how important accurate dating would be.”
Last year, researchers acknowledged potential interference due to the “reservoir effect.” Underwater plants like cirrhosa rupeewhich is underwater ditch grass, can appear much older as they photosynthesize from the water, which often holds ancient carbon, rather than in the atmosphere, which would create a more contemporary picture.
Oviatt teamed up with three colleagues from DRI, the University of Nevada, and Oregon State University to arrange to test cirrhosa rupee samples archived at the University of New Mexico herbarium. They had originally been collected while alive from a nearby spring-fed pool during 1947.
Leading commercial radiocarbon laboratory Beta Analytic conducted dating on those archived samples. The results dated the plants as 7,400 years old, “an offset resulting from the plant’s use of ancient groundwater,” Daily Heritage noted. If those results deviated by 7,400 years, then it is likely that the White Sands footprints would match current records.
“While the researchers recognize 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 carbon from sources other than the current atmosphere – sources that are usually quite old.”
It’s all just the scientific method at work. “The original researchers went to great lengths to substantiate their claims and I’m told they’re still working on it,” Rhode told Artnet News. “They have publicly acknowledged the need for such evidence to convince the community at large. This one is a lot more work now and will continue to be.”
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