a popularly accepted “universal constant” even though the foundations on which it was based have been virtually removed.
Some evidence is also presented to show that radiometric results that are in agreement with the accepted geological time scale are selectively published in preference to those results that are not in agreement.
The requirements of the assumptions in the lead ore method are so extreme it is unlikely that it should give a correct age.” So they took a different approach.
They estimated the age of the Earth by substituting the lead isotope ratios of certain meteorites in the Holmes-Houtermans equation.
Therefore, since the lead isotope ratios for the majority of meteorites are the same as present day common lead ratios and may also be assumed to represent primordial lead, the billion year age chronology disappears.
In case the significance of these results is ignored, a few sentences from the Gale “ …
It might be argued that although radiometric dating has a few problems, the large body of concordant data using different isotopes shows that the dates are of the right order.In 1972 this assumption was shown to be highly questionable.Despite this, the momentum gained in the two decades prior to 1972 has made 4.5 b.y.Briefly, the weakest points in this method are that (a) truly closed systems probably do not exist in nature, “As in the case with radiometric ages determined from almost any rock unit it is impossible to establish unequivocally that the ages reported here reflect the time of original crystallization or emplacement of the bodies from which they are derived.” Before we consider the actual lead/lead isotope data there is one other comment that needs to be made regarding extrapolation of present rates. Five billion years is five million times greater than one thousand years. 2 is 2.5 cm, five million times greater is about 125 km.The radiometric dating method is basically an extrapolation of the form shown in Fig. If the decay constant is known with great accuracy, an extrapolation over one or two thousand years may be regarded as quite reasonable. It should be obvious that the further one projects present rates, the more likely one is to be quite wrong. era started about 1955 with the publication of a classic paper by Patterson In spite of cautions and scepticism advised by the authors this number has been widely and enthusiastically accepted and is usually quoted as if the evidence was decisive and conclusive. Lead-206 and lead-207 are known daughter products from the decay of uranium-238 and uranium-235, respectively.For teaching and sharing purposes, readers are advised to supplement these historic articles with more up-to-date ones suggested in the Related Articles and Further Reading below.