The Young Woman Found In An Idaho Gravel Quarry — And The 12,500-Year-Old Burial That Complicated The Clovis Story
It was, in 1991 when the date was run, among the most reliable methods available for dating organic material.
The result came back: 10,675 ± 95 radiocarbon years before present.
Radiocarbon years and calendar years are not the same thing.
The production of carbon-14 in the atmosphere has not been constant over time, which means that a raw radiocarbon date has to be calibrated against known atmospheric carbon records — derived from tree rings, corals, and other independently dated sources — to produce a calendar age.
The calibration curves in use in the early 1990s were less refined than those available today, but the general picture was clear: a radiocarbon date of 10,675 ± 95 BP translated to a calendar age somewhere in the range of roughly 12,400 to 12,800 years ago — the terminal Pleistocene.