Zircon (Zr Si O) in particular has been the focus of thousands of geochronological studies, because of its ubiquity in felsic igneous rocks and its claimed extreme resistance to isotopic resetting (Begemann et al. However, accurate radioisotopic age determinations require that the decay constants or half-lives of the respective parent radionuclides be accurately known and constant in time. Ideally, the uncertainty of the decay constants should be negligible compared to, or at least be commensurate with, the analytical uncertainties of the mass spectrometer measurements entering the radioisotope age calculations (Begemann et al. Clearly, based on the ongoing discussion in the conventional literature this is still not the case at present. “Rb-Sr Ages of Igneous Rocks from the Apollo 14 Mission and the Age of the Fra Mauro Formation.” Earth and Planetary Science Letters 12 (1): 36–48. However, even uncertainties of only 1% in the half-lives lead to significant discrepancies in the derived radioisotope ages due to how the half-life uncertainties are dealt with in the procedures for propagation of errors (Mattinson 2010; Schoene et al. The recognition of an urgent need to improve the situation is not new (for example, Min et al. It continues to be mentioned, at one time or another, by every group active in geo- or cosmochronology (Boehnke and Harrison 2014; Schmitz 2012). “Equilibrium Pressures of Oxygen Over Oxides of Lead at Various Temperatures.” Journal of the Electrochemistry Society 113 (6): 525–527. From a creationist perspective, the 1997–2005 RATE (arth) project successfully made progress in documenting some of the pitfalls in the radioisotope dating methods, and especially in demonstrating that radioisotope decay rates have not always been constant at today’s measured rates (Vardiman, Snelling, and Chaffin 2000, 2005). Using new samples of feldspar and pumice they ‘reliably dated’ the tuff at 2.61 million years, which agreed nicely.Later, this date was confirmed by two other dating methods (paleomagnetism and fission tracks), and was widely accepted. Although the blook was completed during the summer of 2011, I am still publishing independent articles to the appendix on occasion.I hope you enjoy reading and look forward to interacting with your comments.
So Curtis and others redated the KBS tuff using selected pumice and feldspar samples, and obtained an age of 1.82 million years.
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.
The stunning improvements in the performance of mass spectrometers during the past four or so decades, starting with the landmark paper by Wasserburg et al.
(1969), have not been accompanied by any comparable improvement in the accuracy of the decay constants (Begemann et al.
These uncertainties are compounded by the underlying unprovable assumptions on which the radioisotope dating methods are based, especially the assumption of time-invariant decay rates, built on the foundation of an assumed deep time history. “Formation of the ‘Great Unconformity’ as a Trigger for the Cambrian Explosion.” Nature 484 (7394): 363–366.