Radioactive method for dating rock
The man's body was recovered and pieces of tissue were studied for their C content by accelerator mass spectroscopy.
The best estimate from this dating technique says the man lived between 33 BC. From the ratio, the time since the formation of the rock can be calculated.
Absolute dating is used to determine a precise age of a fossil by using radiometric dating to measure the decay of isotopes, either within the fossil or more often the rocks associated with it.
The majority of the time fossils are dated using relative dating techniques.
Using relative dating the fossil is compared to something for which an age is already known.
For example if you have a fossil trilobite and it was found in the Wheeler Formation.
Then after another 5,000 years half of the remaining parent isotope will have decayed.
While people are most familiar with carbon dating, carbon dating is rarely applicable to fossils.
If the fossil you are trying to date occurs alongside one of these index fossils, then the fossil you are dating must fall into the age range of the index fossil. In a hypothetical example, a rock formation contains fossils of a type of brachiopod known to occur between 410 and 420 million years.
The same rock formation also contains a type of trilobite that was known to live 415 to 425 million years ago.
Since the rock formation contains both types of fossils the ago of the rock formation must be in the overlapping date range of 415 to 420 million years.
Scientists can use certain types of fossils referred to as index fossils to assist in relative dating via correlation.
Index fossils are fossils that are known to only occur within a very specific age range.