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 fact, there is no large body of concordant data.Since the lead in meteorites can no longer be ascribed to uranium/thorium decay, it may also be taken to represent primordial lead.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.magazine has been continuously published since 1978, we are publishing some of the articles from the archives for historical interest, such as this.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.
The basic theory of radiometric dating is briefly reviewed.
They estimated the age of the Earth by substituting the lead isotope ratios of certain meteorites in the Holmes-Houtermans equation.
In this equation the primordial lead ratios are required.
That difficulty aside, they were selected because they contain very little uranium and thorium and are therefore unlikely to contain significant radiogenic lead.
However, it is even more surprising to learn that the lead isotope ratios chosen by Patterson Most meteorites have lead isotope ratios similar to those of present day common lead.
Up until 1972 these could be explained as being contaminated with radiogenic lead from uranium and thorium decay.