Carbon dating age of
Thus, no one even considers using carbon dating for dates in this range.In theory, it might be useful to archaeology, but not to geology or paleontology.Since it would only take less than 50,000 years to reach equilibrium from a world with no C-14 at the start, this always seemed like a good assumption.That is until careful measurements revealed a significant disequalibrium. All the present C-14 would accumulate, at present rates of production and build up, in less than 30,000 years!Carbon-14 has a half-life of 5,730 ± 40 years, meaning that every 5,700 years or so the object loses half its carbon-14.Samples from the past 70,000 years made of wood, charcoal, peat, bone, antler or one of many other carbonates may be dated using this technique. As soon as a living organism dies, it stops taking in new carbon.The ratio of carbon-12 to carbon-14 at the moment of death is the same as every other living thing, but the carbon-14 decays and is not replaced.
After death the amount of carbon-14 in the organic specimen decreases very regularly as the molecules decay.However, radioisotope dating may not work so well in the future.Anything that dies after the 1940s, when Nuclear bombs, nuclear reactors and open-air nuclear tests started changing things, will be harder to date precisely.Other useful radioisotopes for radioactive dating include Uranium -235 (half-life = 704 million years), Uranium -238 (half-life = 4.5 billion years), Thorium-232 (half-life = 14 billion years) and Rubidium-87 (half-life = 49 billion years).The use of various radioisotopes allows the dating of biological and geological samples with a high degree of accuracy.