How to date a fossil using radiometric dating
When an organism dies it ceases to replenish carbon in its tissues and the decay of carbon 14 to nitrogen 14 changes the ratio of carbon 12 to carbon 14.Experts can compare the ratio of carbon 12 to carbon 14 in dead material to the ratio when the organism was alive to estimate the date of its death.
So we know that C came before D—but because D is igneous, we can put a date on it (now I have a Beyoncé song in my head, great…).
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!