Lead isotopes are commonly used in dating rocks and provide some of the best evidence for the Earth's age. In order to be used as a natural clock to calculate the age of the earth, the processes generating lead isotopes must meet the four conditions of a natural clock: an irreversible process, a uniform rate, an initial condition, and a final condition. Dalrymple cites examples of lead isotope dating that give an age for the earth of about 4. Lead isotopes are important because two different lead isotopes Pb and Pb are produced from the decay series of two different uranium isotopes U and U. Since both decay series contain a unique set of intermediate radioactive isotopes, and because each has its own half-life, independent age calculations can be made from each Dalrymple
The Age of the Earth - Lead Isotopes as a Current Scientific Clock: Paul Bechard
The simplest form of isotopic age computation involves substituting three measurements into an equation of four variables, and solving for the fourth. The equation is the one which describes radioactive decay:. Solving the equation for "age," and incorporating the computation of the original quantity of parent isotope, we get:. Some assumptions have been made in the discussion of generic dating, for the sake of keeping the computation simple. Such assumptions will not always be accurate in the real world. These include:. If one of these assumptions has been violated, the simple computation above yields an incorrect age.
This book is a compilation of seven Creation Research Society Quarterly reprints published by the Creation Research Society , two reprints from the Proceedings of the International Conference on Creationism , and one reprint of an Institute for Creation Research Impact pamphlet. All of the papers were written by Woodmorappe and each address various topics relating to the young-earth creationist belief in a geologically-recent global deluge Noah's Flood. The book has no publisher's information page but it seems clear from the Forward , written by the well-known young-earth creationist Henry Morris, that it was published by the Institute for Creation Research in On the cover of the book, John Woodmorappe is credited with possessing an M. The Impact reprint in the book states that:.
Radioactive decay has become one of the most useful methods for determining the age of formation of rocks. However, in the very principal of radiometric dating there are several vital assumptions that have to be made in order for the age to be considered valid. These assumptions include: 1 the initial amount of the daughter isotope is known, 2 neither parent or daughter product has migrated into, or out of, the closed rock system, and 3 decay has occurred at a constant rate over time. But what if one or some combination of these assumptions is incorrect? Then the computed age based on the accumulation of daughter products will be incorrect Stasson