The second implication is the one that creates the dating problem.

The fish she was eating were living in the Snake River system, and the Snake River system carries carbonate-rich water from the volcanic and sedimentary geology it traverses.

If those fish had bone collagen enriched with radiocarbon-dead carbon from the freshwater reservoir, and if the Buhl Woman’s own bone collagen reflects the fish she ate, then the radiocarbon date on her bone reflects not just the atmospheric carbon at the time of her death but also the mixed-age carbon that came through her diet.

The isotope evidence that makes her life most vivid — that she lived on meat and fish in the terminal Pleistocene Snake River landscape — is the same evidence that most strongly suggests the date on her bones cannot be accepted without qualification.