Organic remains contain a built-in chronological signal. Radiocarbon dating measures the decay of carbon-14 in once-living material to estimate the time since death. The method has transformed archaeology and late Quaternary studies since its development in the mid-twentieth century.

While alive, organisms exchange carbon with the atmosphere; after death the radioactive isotope decays at a known rate. Measuring the remaining carbon-14 yields an age before present, subject to calibration against tree-ring and other records that correct for past variations in atmospheric concentration.

The technique works best on samples up to about 50,000 years old. Contamination, reservoir effects, and calibration uncertainties require careful sampling and interpretation. Despite limitations, radiocarbon dating provides absolute ages that anchor relative sequences and link archaeological sites across regions.

• Dating method using carbon-14 decay
• Applies to organic materials
• Requires calibration for accuracy
• Essential tool in archaeology and paleoscience