Dating permission form
The amount of initial wouldn't change over time -- because it would have no parent atoms to produce daughter atoms.It is not easily explained, in the general case, in any other way.The data points would be expected to start out on a line if certain initial conditions were met.There are minor differences between isotopes of the same element, and in relatively rare circumstances it is possible to obtain some amount of differentiation between them. The effect is almost always a very small departure from homogeneous distribution of the isotopes -- perhaps enough to introduce an error of 0.002 half-lives in a non-isochron age. but it is rare and the effect is not large enough to account for extremely old ages on supposedly young formations.) as minerals form.
This results in a range of X-values for the data points representing individual minerals.
Note that the mere existence of these assumptions do not render the simpler dating methods entirely useless.