The Mayan calendar used 3114 BC as their reference.
More recently is the radiocarbon date of 1950 AD or before present, BP.
Radiocarbon dating is a method of estimating the age of organic material.
As you learned in the previous page, carbon dating uses the half-life of Carbon-14 to find the approximate age of certain objects that are 40,000 years old or younger.
In the following section we are going to go more in-depth about carbon dating in order to help you get a better understanding of how it works.
Plants and animals naturally incorporate both the abundant C-12 isotope and the much rarer radiocarbon isotope into their tissues in about the same proportions as the two occur in the atmosphere during their lifetimes.
When a creature dies, it ceases to consume more radiocarbon while the C-14 already in its body continues to decay back into nitrogen.
C-14 is produced in the upper atmosphere when nitrogen-14 (N-14) is altered through the effects of cosmic radiation bombardment (a proton is displaced by a neutron effectively changing the nitrogen atom into a carbon isotope).
The new isotope is called "radiocarbon" because it is radioactive, though it is not dangerous.Since only 1 mg of carbon is required for accelerator mass spectrometry (AMS), very small iron samples can now be analyzed (50 mg of a 2.0% C iron or 1 g of a 0.1% C iron).We anticipate that this methodology will be particularly useful to archeologists who currently have to rely on context to date iron artifacts.The resulting CO2 was graphitized routinely using hydrogen reduction (Vogel et al . After the initial phase of development, carbon yields of 100% were consistently obtained.The activities of two modern high carbon steels (treated as process blanks, manufactured using only coal as the carbon source) were determined to be 0.0077 ± 0.0009 (n = 12, ± 1 σ ) for a 1.3% C steel and 0.0090 ± 0.0038 (n = 12, ± 1 σ ) for a 1.9% C steel, indicating that very little contamination is introduced during the sample preparation process.It takes another 5,730 for half of the remainder to decay, and then another 5,730 for half of what's left then to decay and so on.