Potassium argon dating wiki

19-Aug-2015 12:54

What simplifies things is that potassium is a reactive metal and argon is an inert gas: Potassium is always tightly locked up in minerals whereas argon is not part of any minerals. So assuming that no air gets into a mineral grain when it first forms, it has zero argon content.

It is based on measurement of the product of the radioactive decay of an isotope of potassium (K) into argon (Ar).Given careful work in the field and in the lab, these assumptions can be met.The rock sample to be dated must be chosen very carefully.Lava flows that lie above and below rock beds with ancient human fossils are a good—and true—example.Any alteration or fracturing means that the potassium or the argon or both have been disturbed.

It is based on measurement of the product of the radioactive decay of an isotope of potassium (K) into argon (Ar).

Given careful work in the field and in the lab, these assumptions can be met.

The rock sample to be dated must be chosen very carefully.

Lava flows that lie above and below rock beds with ancient human fossils are a good—and true—example.

Any alteration or fracturing means that the potassium or the argon or both have been disturbed.

The site also must be geologically meaningful, clearly related to fossil-bearing rocks or other features that need a good date to join the big story.