The prefix radio as in radiometric dating means
2006; Schön, Winkler and Kutschera 2004; Snelling 2017a; Villa et al. It is to be expected that every long-lived radioactive isotope is likely to show similar variation and uncertainty in half-life measurements because these are difficult measurements to make.
However, even small variations and uncertainties in the half-life values result in large variations and uncertainties in the calculated ages for rocks and minerals due to how the half-life uncertainties are dealt with in the procedures for propagation of errors (Mattinson 2010; Schoene et al. This, of course, in no way diminishes or casts uncertainties on the conclusions of the RATE project that radioisotope decay rates have not always been constant at today’s measured rates, and that as a result radioisotope ages can still be used as relative ages (Vardiman, Snelling, and Chaffin 2000, 2005).
Yet the question still remains as to whether the half-life values for each long-lived parent radioisotope are independently determined.
Nevertheless, accurate radioisotope age determinations not only depend on accurate determinations of the decay constants or half-lives of the respective parent radioisotopes, but on the reliability of the three assumptions these supposed absolute dating methods rely on.
Data points that do not fit on the isochron are simply ignored because their values are regarded as due to contamination. 2001; Steiger and Jäger 1977), in spite of ongoing attempts (Miller 2012). The uncertainties associated with direct half-life determinations are, in most cases, still at the 1% level, which is still significantly better than any radioisotope method for determining the ages of rock formations. “The Metamict State.” American Mineralogist 37 (3–4):137–157. The recognition of Pb loss from minerals after they form to explain discordant dates has resulted in the demonstration that both U and Pb mobility can occur in them.
But how much U and Pb have been mobilized and how far they have migrated cannot be known with certainty.
Minerals such as zircon are routinely used by geochronologists to confidently provide the U-Pb and Pb-Pb ages which underpin the conventional multi-millions-of-years’ timescale.