Radioisotopes in carbon dating


Libby received the Nobel Prize in Chemistry for his work in 1960.

The radiocarbon dating method is based on the fact that radiocarbon is constantly being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen.

Radiocarbon dating, or carbon-14 dating, can be used to date material that had its origins in a living thing as long as the material contains carbon.

Some materials that do not contain carbon, like clay pots, can be dated if they were fired in an oven (burnt) and contain carbon as a result of this.

For example, two samples taken from the tombs of two Egyptian kings, Zoser and Sneferu, independently dated to 2625 BC plus or minus 75 years, were dated by radiocarbon measurement to an average of 2800 BC plus or minus 250 years. Carbon dioxide produced in this way diffuses in the atmosphere, is dissolved in the ocean, and is taken up by plants via photosynthesis.

Animals eat the plants, and ultimately the radiocarbon is distributed throughout the biosphere.

Radiocarbon dating has allowed key transitions in prehistory to be dated, such as the end of the last ice age, and the beginning of the Neolithic and Bronze Age in different regions.