Accelerator mass spectrometry measures the amount of carbon-14, or radiocarbon, present in a sample, which can be used to calculate its age.Around the world, only about 100 facilities house this equipment.
A new spectroscopic technique offers ultra-sensitive optical detection of radiocarbon dioxide.
But as more dates became available, Egyptologists, who had hieroglyphic records back thousands of years, began to recognize that C-14 dates were generally too young.
They proved this by showing that C-14 dates of wooden artifacts with cartouches (dated royal names) did not agree.
The latest complete list of radiocarbon readings received from America brings the total number of dated sites and objects to upwards of 160.
Of these 120 are from localities in the New World, and their archaeological implications have been reviewed by G. S, Bushneil in the last number of ANTIQUITY; the object of the present article is to do the same for the 40 odd results available from the Old World.
The other two isotopes in comparison are more common than carbon-14 in the atmosphere but increase with the burning of fossil fuels making them less reliable for study (2); carbon-14 also increases, but its relative rarity means its increase is negligible. After this point, other Absolute Dating methods may be used.