Dating uranium 238 marine rules regarding dating
That this is common practice is illustrated with numerous examples cited from the literature by Faure and Mensing (2005) and Dickin (2005).
On the other hand, it could be argued that this discarding of data points which do not fit the isochron is arbitrary and therefore is not good science, because it is merely assumed the “aberrant” values are due to contamination rather than that being proven to be so.
U decay constants and half-lives have been made using direct counting experiments and geological age comparisons, as well as by critical reviews and reevaluations of those determinations. “Natural Reactor Studies.” In Uranium in the Pine Creek Geosyncline.
By 1971 the direct counting experiments had provided U half-life values with small uncertainties which ever since have been the recommended values used in all U-Pb age calculations.
However, even uncertainties of only 1% in the half-lives lead to very significant discrepancies in the derived radioisotope ages. 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. 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. But there have still been repeated calls for more modern, more accurate direct counting experiments to more precisely determine the U half-life by forced agreement of Rb-Sr, Lu-Hf, Re-Os, Sm-Nd, K-Ar, and Ar-Ar ages respectively with U-Pb ages obtained for the same rocks, minerals and meteorites, none of these decay half-lives are really known accurately. “New Average Values for n(U) Isotope Ratios of Natural Uranium Standards.” International Journal of Mass Spectrometry 295 (1–2): 94–97. Therefore, without accurately known decay half-lives, all radioisotope ages cannot be accurately determined or be considered absolute ages.