Arndts and Overn (8) and Kramer yet others (78) declare that Rb-Sr isochrons would be the total consequence of blending, as opposed to of decay of 87 Rb over long stretches:
It really is clear that blending of pre-existent materials will produce an array that is linear of ratios. We require perhaps not assume that the isotopes, assumed to be child isotopes, had been in reality manufactured in the rock by radioactive decay. Hence the presumption of immense many years will not be proven.
(8, p. 6)
These writers remember that it’s mathematically feasible to make a right line on a Rb-Sr isochron diagram by blending, in a variety of proportions, two end users of various 87 Sr/ 86 Sr and 87 Rb/ 86 Sr compositions.
A test often used to check on for blending would be to plot the 87 Sr/ 86 Sr ratio against 1/Sr (49).
This plot shows whether or not the 87 Sr/ 86 Sr ratio differs methodically with all the Sr content of this samples that are various, as is the instance in the event that isochron had been due to combining in the place of radioactive to decay as time passes. Kramer as well as others (78) have analyzed the information from 18 Rb-Sr isochrons published into the literature that is scientific plotting the 87 Sr/ 86 Sr ratio versus 1/Sr and determining the correlation coefficient (C.C. ) to check for linear relations: