Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples.Carbon-14 was discovered on 27 February 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, California.This allows the dating of much older and smaller samples but at a far higher cost.Although, organic materials as old as 100,000 years potentially can be dated with AMS, dates older than 60,000 years are still rare.The different isotopes of carbon do not differ appreciably in their chemical properties.This resemblance is used in chemical and biological research, in a technique called carbon labeling: carbon-14 atoms can be used to replace nonradioactive carbon, in order to trace chemical and biochemical reactions involving carbon atoms from any given organic compound.
C, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.
Paleoanthropologists and archaeologists must always be aware of possible radiocarbon sample contamination that could result in inaccurate dates.
Carbon dating is used to determine the age of biological artifacts up to 50,000 years old.
Small amounts of carbon-14 are not easily detected by typical Geiger–Müller (G-M) detectors; it is estimated that G-M detectors will not normally detect contamination of less than about 100,000 disintegrations per minute (0.05 µCi).
This clock representation shows some of the major units of geological time and definitive events of Earth history.