The Castlepook Question
“Before present” conventionally means before AD 1950, whereas BCE dates are a later conversion. Around 34,000 years ago, even well-preserved organic material does not yield calendar precision of the kind implied by a numbered year. Atmospheric radiocarbon varied through time, and the calibration curve becomes especially consequential beyond 30,000 calendar years ago. A bone’s laboratory result, its calibrated range, the layer from which it came and the possibility of later disturbance all need separate consideration. Consequently, this article uses “around”, “about” and calibrated ranges where the evidence permits; it does not claim that any animal, group or occurrence can be assigned to 31,907 BCE itself.