C (the period of time after which half of a given sample will have decayed) is about 5,730 years, the oldest dates that can be reliably measured by this process date to approximately 50,000 years ago, although special preparation methods occasionally make accurate analysis of older samples possible.

What length of time can radiocarbon dating be used for?

Because of this relatively short half-life, radiocarbon dating has a useable range of ~ 300 to ~ 50,000 years (Briner, 2011; Guilderson et al., 2005).

Is radiocarbon dating accurate to 70000 years?

However, if the bone is 70,000 years or older the amount of 14C left in the bone will be too small to measure accurately. Thus, radiocarbon dating is only useful for measuring things that were formed in the relatively recent geologic past.