Opyros writes: Fossil footprints in New Mexico have been dated to 21,000-23,000 years before present. As a result, human habitation of the Americas can be pushed back several thousand years. The footprints were found in sedimentary rock at White Sands National Park, near the location of a long-vanished lake. Since the rock contains seeds of ditchgrass, it was possible to apply radiocarbon dating, leading to the remarkably early date. Until now, the oldest unequivocally dated signs of human presence in the New World were only 16,000 years old. Hence the great significance of the find.
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