Relative dating techniques for kids
Various methods have been devised to determine this initial or common Pb, but all involve making unprovable assumptions.Zircon does incorporate initial Pb when it crystallizes. It cannot be proven that the Pb in apparently cogenetic U- or Th-free minerals is only initial Pb, and that it is identical to the initial Pb in the mineral being dated.U decay in those rocks added daughter Pb isotopes to the common or initial Pb isotopes in them, inherited from the rock’s sources.So the Pb isotope ratios measured in these rocks today must be interpreted before their U-Pb ages can be calculated.There is thus no impediment to accepting and using the Bible’s account of Creation and the Flood as a reliable framework for unravelling the history of the earth and the Pb isotopes found in its minerals and rocks.Radioisotope dating of minerals, rocks and meteorites is perhaps the most potent claimed proof for the supposed old age of the earth and the solar system.
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.
There is also primordial Pb that the earth acquired when it formed, its isotopic composition determined as that of troilite in the Canyon Diablo iron meteorite.
Subsequently new crustal rocks formed via partial melts from the mantle.
One crucial area the RATE project did not touch on was the issue of how reliable are the determinations of the radioisotope decay rates, which are so crucial for calibrating these dating “clocks.” However, in a recent series of papers, Snelling (2014a, b, 2015a, b, 2016, 2017) reviewed how the half-lives of the parent radioisotopes used in long-age geological dating have been determined and collated all the determinations of them reported in the literature to discuss the accuracy of their currently accepted values.
He documented the methodology behind and history of determining the decay constants and half-lives of the parent radioisotopes U which are used as the basis for the Rb-Sr, Lu-Hf, Re-Os, Sm-Nd, K-Ar, Ar-Ar, U-Pb, and Pb-Pb long-age dating methods respectively.These new rocks rapidly accumulated more Pb isotopes due to the concurrent accelerated radioactive decay of U and Th in them during the Flood.