A much more precise method of radio-dating depends on the decay of the isotope potassium chemical abbreviation K to form argon chemical abbreviation Ar through beta decay, with a half life of 1. The creationists, of course, cannot accept an age for the earth of approximately 4. And meteors and moon rocks also date to about 4. However, since in the uranium-lead process there is no way of precisely determining the original amount of primordial lead the best we can do is use an estimate based on the average concentration of lead found todaysome error is introduced in this part of the calculation most radio-dates using the uranium-lead techniques vary by a few percent plus or minus. Radiogenic Isotope Geology 2nd ed.
Wetherill has shown that the two points on the Concordia curve intersected by this straight line will represent the time of initial crystallization and the time of the subsequent lead loss.
Contributions to Mineralogy and Petrology4: If the decay rate was faster or slower in the past than it is now, the entire method becomes unreliable. University of Wisconsin-Madison Chemistry Department. In the K-Ar and Rb-Sr methods, however, there are methods of precisely determining the ratios of radio-element and radiogenic daughter element, as well as ways to determine if the sample has been contaminated. Lunisolar Solar Lunar Astronomical year numbering.