Rodents, for example, can create havoc in a site by moving items from one context to another.
The Mayan calendar used 3114 BC as their reference.
More recently is the radiocarbon date of 1950 AD or before present, BP.
Plankton absorbs, Carbon-14 from the ocean much like terrestrial plants absorb Carbon-14 from the air.
Since plankton is the foundation of the marine food chain, Carbon-14 is spread throughout aquatic life.
There are two techniques for dating in archaeological sites: relative and absolute dating.
Relative dating stems from the idea that something is younger or older relative to something else.
Looking at the graph, 100% of radiocarbon in a sample will be reduced to 50% after 5730 years.
In 11,460 years, half of the 50% will remain, or 25%, and so on.
In 1949, American chemist Willard Libby, who worked on the development of the atomic bomb, published the first set of radiocarbon dates.
His radiocarbon dating technique is the most important development in absolute dating in archaeology and remains the main tool for dating the past 50,000 years.
Therefore, radiocarbon dates need to be calibrated with other dating techniques to ensure accuracy.