An absolute dating method that estimates the calendar age of formerly living organic material by measuring the remaining concentration of the radioactive isotope carbon-14 (14C) produced in the biosphere and applying its known decay rate; results require calibration to convert radiocarbon ages into calendar dates and are reported with an uncertainty range.

Principle

Because living organisms incorporate atmospheric carbon with a measurable proportion of 14C, and 14C decays at a known exponential rate after death, the remaining 14C concentration in a sample indicates the time elapsed since the organism stopped exchanging carbon with the atmosphere—subject to calibration for variations in atmospheric 14C and accounting for contamination or reservoir effects.

Demonstration

Illustrative Scenario → Situation: A charred seed is recovered from a sealed midden layer. Recognition: Laboratory measurement shows a reduced 14C concentration relative to modern standards. Action: Analysts calculate a radiocarbon age, apply a calibration curve to obtain a calendar age range, and report the date with its uncertainty and the sample context. Consequence: The calibrated age provides an absolute chronological constraint for the midden phase and can test seriation or stratigraphic hypotheses.

Misapplication

Using an uncalibrated radiocarbon age as a calendar date or dating material that is not in direct association with the archaeological event of interest (e.g., old wood or redeposited charcoal). The error conflates the radiocarbon measurement with calibrated calendar age and ignores reservoir or contamination effects.

Consequence

Correct use produces absolute chronological constraints with quantifiable uncertainties that can anchor relative sequences and test hypotheses; misuse yields misleading calendar attributions, false precision, or chronological offsets due to reservoir effects, contamination, or inappropriate sample selection.

Reversal

Radiocarbon dating is limited where samples lack sufficient organic carbon, where reservoir effects (marine, freshwater, old-carbon) alter apparent 14C content, where contamination cannot be excluded, or for very recent or very ancient time ranges beyond method sensitivity; calibration curves and pretreatment methods must be applied and reported.

Boundary

Clearly within: Dating short-lived, contextually secure organic samples (seeds, bone collagen) and reporting calibrated age ranges with uncertainty and lab methods. Boundary case: Dating charcoal from long-lived wood where the measured age may predate the event (old-wood effect). Clearly outside: Assigning precise calendar decades to artifacts solely from raw radiocarbon ages without calibration or context.

Semantic Tension

Absolute Dating ↔ Sample Association/Context — radiocarbon provides ages for material, but its archaeological meaning depends on demonstrable association between dated material and the event or object of interest.

Synthesis

Radiocarbon dating yields laboratory-based age estimates tied to physical samples; their archaeological interpretation requires careful sample selection, pretreatment, calibration, and explicit reporting of uncertainties and context.