Waikato university radiometric dating
It takes 5,730 years for half the carbon14 to change to nitrogen; this is the halflife of carbon14.
After another 5,730 years only onequarter of the original carbon14 will remain.
One of the most widely used is the Potassium-argon_dating (K/A) technique.
Carbon14 moves up the food chain as animals eat plants and as predators eat other animals.The stone map inscriptions may have contaminated by foreign material from any time period in history.In addition the stone maps are not believed to be 600 years old, so they don't meed the first criteria for radiocarbon dating.This is a radiometric technique since it measures radioactive decay.Carbon14 is an unstable isotope of normal carbon, carbon12.