Because argon is inert, it cannot be chemically incorporated in the minerals when they are formed, but it can be physically trapped in the rocks either during or after formation. If the source of this argon is atmospheric contamination, then we can correct for this.
For these reasons K-Ar dating has largely been superseded by Ar-Ar dating, which will be the subject of the next article.
, so use of this dating method to determine the ratio of daughter calcium produced from parent potassium is generally not practical.
If the mineral composition of the two sample is different, so that the sample for measuring the potassium is richer or poorer in potassium than the sample used for measuring the argon, then this will be a source of error.
Another concern with K-Ar dating is that it relies on there being no Ar in the rock when it was originally formed, or added to it between its formation and our application of the K-Ar method.
Potassium-Argon Dating Potassium-Argon dating is the only viable technique for dating very old archaeological materials.