A field glossary.
ka
Thousands of years ago. Check the datum used in the source.
cal BP
Calibrated calendar years before 1950.
Argon-argon
An isotopic dating method applied to suitable geological material; association links it to archaeology.
Luminescence
Estimates time since mineral grains were last exposed to light or heat, subject to method and context.
Reservoir effect
An apparent radiocarbon age offset when a sample incorporates older carbon.
U-series
Uses uranium decay products in suitable materials; overlying calcite can provide a minimum age for art.
Genomic
Analysis of DNA. Admixture timing is model-dependent and distinct from direct bone dating.
See each case’s dating discussion for its specific use and sources.