In order for the initial amount of the daughter isotopes to be known, the isotopes have to be uniformly distributed throughout a rock formation when it solidifies, and it must solidify slowly enough for this uniformity to occur.
Yet, when five radiometric dating methods agree on the age of one of the Earth's oldest rock formations Dalrymplep.
The following are interesting questions that were asked in talk.
Description: This is true even if the earth were really 4. Thus, the Earth and the atmosphere now contain about equal amounts of 40 Ar, and the total could be generated if the Earth contained only ppm potassium and released half of its 40 Ar to the atmosphere.