By about 8,000 years ago, inhabitants of what is now the United States were making and wearing sophisticated sandals and slip-on shoes, according to researchers who analyzed a rare sampling of ancient footwear.
Prehistoric North Americans apparently fashioned shoes in regional styles using a variety of materials and techniques, contend archaeologist Michael J. O'Brien of the University of Missouri at Columbia and his coworkers.
O'Brien's group applied accelerator mass spectrometer (AMS) dating to 7 of 18 footwear specimens discovered more than 40 years ago in central Missouri's Arnold Research Cave.
"The design and weaving observed in the oldest specimen are about as complex as what we see in later ones that we've dated to around 1,000 years ago," O'Brien says. "These people knew exactly what they were doing."
Radiocarbon dating of sediment at the Missouri cave suggests that it was occupied as early as 11,000 years ago, O'Brien says. Researchers had not previously dated footwear at the site because the traditional radiocarbon method would have destroyed large portions of the items. The AMS technique uses tiny samples to measure the presence of different forms of carbon.
Two types of shoes appear in the Missouri collection. …