Derryvree’s Sub-Till Wetland
The principal difficulty is chronological as well as archaeological. Radiocarbon measurements are not calendar dates: they must be calibrated against changing levels of atmospheric carbon-14, and at this antiquity their calibrated results can span centuries or millennia. IntCal20, the current internationally used Northern Hemisphere calibration curve, reaches back to 55,000 calibrated years before present but makes no claim that every sample can be dated to a precise year. A date such as 31,827 BCE is consequently useful for arranging a modern archive, but it must not be mistaken for the resolution of the evidence.