How to date a fossil using radiometric dating
Radiocarbon dating can be used on samples of bone, cloth, wood and plant fibers.
The half-life of a radioactive isotope describes the amount of time that it takes half of the isotope in a sample to decay.
Carbon is naturally in all living organisms and is replenished in the tissues by eating other organisms or by breathing air that contains carbon.
At any particular time all living organisms have approximately the same ratio of carbon 12 to carbon 14 in their tissues.
Archaeologists use the exponential, radioactive decay of carbon 14 to estimate the death dates of organic material.
If the amount of carbon 14 is halved every 5,730 years, it will not take very long to reach an amount that is too small to analyze.
So if you try to run radiometric dating on a sedimentary rock, you won’t determine the age of that rock—that is, when the sediments were compacted and cemented to form a new layer. However, there is a problem, a really big one: Its half-life is only 5730 years.
Instead, you’ll determine how long ago the rock formed—not very helpful. It might not seem like it, but that is a really short half-life, and Ealong.
So, the fossil is 8,680 years old, meaning the living organism died 8,680 years ago.
I want to start this week’s entry by saying that I really hadn’t intended this topic to take up three posts!