absolute dating

Absolute dating is the process of determining an age on a specified chronology in archaeology and geology. Absolute dating provides a numerical age or range, in contrast with relative dating, which places events in order without any measure of the age between events. Some scientists prefer the terms chronometric dating or calendar dating, as the use of the word "absolute" may imply an unwarranted certainty of accuracy.

In archaeology, absolute dating is usually based on the physical, chemical, and life properties of the materials of artifacts, buildings, or other items that have been modified by humans and by historical associations with materials with known dates (such as coins and historical records). For example, coins found in excavations may have their production date written on them, or there may be written records describing the coin and when it was used, allowing the site to be associated with a particular calendar year. Absolute dating techniques include radiocarbon dating of wood or bones, potassium-argon dating, and trapped-charge dating methods such as thermoluminescence dating of glazed ceramics.