Therefore we can assume that the entire lead content of the zircon is radiogenic.Where this is not the case, a correction must be applied.
Thus, if we start out with 1 gram of the parent isotope, after the passage of 1 half-life there will be 0.5 gram of the parent isotope left.
After the passage of two half-lives only 0.25 gram will remain, and after 3 half lives only 0.125 will remain etc.
However, use of a single decay scheme (usually Pb) leads to the U-Pb isochron dating method, analogous to the rubidium-strontium dating method.
Finally, ages can also be determined from the U-Pb system by analysis of Pb isotope ratios alone. Clair Cameron Patterson, an American geochemist who pioneered studies of uranium-lead radiometric dating methods, is famous for having used it to obtain one of the earliest accurate estimates of the age of the Earth.
The energies involved are so large, and the nucleus is so small that physical conditions in the Earth (i.e. The rate of decay or rate of change of the number N of particles is proportional to the number present at any time, i.e.
The half-life is the amount of time it takes for one half of the initial amount of the parent, radioactive isotope, to decay to the daughter isotope.
Exploration over the years has confirmed that many of these cratons have indicator mineral chemistry in the diamond stability field.
In northern Canada, it takes a combination of mineral chemistry, knowledge of regional ice advance and retreat patterns, and geophysical sleuthing to find potentially diamond-bearing kimberlites.
"There are some very high grade discoveries going under the radar screen," Pamela Strand, president and CEO of Edmonton-based Shear Minerals, told members of the Canadian Institute of Mining (CIM) and Women in Mining (WIM) at a joint luncheon in Toronto.
Some companies are investigating areas that have never been explored for diamonds before but show potential for the diamond host rock, kimberlite, while others are re-evaluating old prospects by revisiting data with faster and more sophisticated processing techniques.
Prior to 1905 the best and most accepted age of the Earth was that proposed by Lord Kelvin based on the amount of time necessary for the Earth to cool to its present temperature from a completely liquid state.