Range of potassium argon dating

05 Feb

One thing to keep in mind is that high-precision isotope measurements always measure ratios between isotopes, not absolute concentrations.

Argon-argon dating gets around many of the issues by measuring only multiple isotopes of argon.

The trick is to irradiate the sample with neutrons along with samples of known age.

However, because each of these parameters is difficult to determine independantly, a mineral standard, or monitor, of known age is irradiated with the samples of unknown age.

The monitor flux can then be extrapolated to the samples, thereby determining their flux.

To understand argon-argon dating, you need to understand potassium-argon dating.

The isotope potassium-39 makes up about 93% of natural potassium.

The standards of known age are used to account for differences in the neutron flux during irradiation.

Argon-36 in the sample accounts for any air contamination.