(You can read up on radioactivity and isotopes here).
The age of the carbon in the rock is different from that of the carbon in the air and makes carbon dating data for those organisms inaccurate under the assumptions normally used for carbon dating.
This restriction extends to animals that consume seafood in their diet.
The Mayan calendar used 3114 BC as their reference.
More recently is the radiocarbon date of 1950 AD or before present, BP.
Chemically, carbon-14 is no different from non-radioactive carbon atoms, so it ends up in all the usual carbon places — one trillionth of the carbon atoms in air, plants, animals and us are radioactive.
All radioactive atoms eventually decay into something more stable, and carbon-14 decays into nitrogen.Specifically, each nucleus will lose an electron, a process which is referred to as decay.This rate of decay, thankfully, is constant, and can be easily measured in terms of ‘half-life’.In a stratigraphical context objects closer to the surface are more recent in time relative to items deeper in the ground.Although relative dating can work well in certain areas, several problems arise.At least to the uninitiated, carbon dating is generally assumed to be a sure-fire way to predict the age of any organism that once lived on our planet.