Radiometric dating of sedimentary rocks
However, that doesn’t mean that you can’t help to push against the misconception that all fossils are dated directly.
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 it’s not like there is one magic temperature that locks these things in. Carbon-14 is a radioactive form of carbon that is widely used in radiometric dating.
It’s all a bit mathy, but the good thing is, people have figured it out and can account for it no matter the rock type or the radiometric method being used.) But, when it comes to fossils, we’re primarily interested in sedimentary rock layers, which, you’ll recall, form from pre-existing rock material. Very occasionally, there may be some remaining organic material in a fossil that could, hypothetically, be dated using carbon-14.
As the rock cools, there comes a point, called the closing temperature, when parent and daughter isotopes can no longer diffuse into or out of the rock system—at that point, the clock is set.
(It’s worth mentioning that this temperature varies by rock type and by isotope!