Fermanagh’s Freshwater Silts
Radiocarbon dates are not calendar dates. A laboratory measurement records the remaining radioactive carbon in a sample and is conventionally expressed in radiocarbon years BP; it must then be calibrated against independently dated records of changing atmospheric carbon. At the depths of time involved here, calibration can produce broad and sometimes discontinuous probability ranges. A date such as 31,874 BCE is consequently useful only as a modern reference marker: it cannot identify a season, a generation, or even a discrete archaeological horizon. The relevant evidence comes instead from deposits whose ranges overlap that point in time.