The earth has been determined by radiometric dating to be dating going through the motion
Although this is a potential source of error for terrestrial rocks, it is irrelevant for lunar rocks and meteorites, as there are no chemical weathering reactions in those environments.
Initial Nd ratios as well) the geological fingerprint of an object or skeleton can be measured, allowing migration patterns to be determined.
From there, we can begin to calculate the age of the earth.
Let’s do a rough calculation to show how this works.
The Rb-Sr dating method has been used extensively in dating terrestrial and lunar rocks, and meteorites.
If the initial amount of Sr is known or can be extrapolated, the age can be determined by measurement of the Rb and Sr concentrations and the Sr ratio.
A Rb-Sr date which is at variance with other geochronometers may not be useless, it may be providing data on an event which is not representing the age of formation of the rock.
In addition, Rb is a highly incompatible element that, during partial melting of the mantle, prefers to join the magmatic melt rather than remain in mantle minerals. The radiogenic daughter, Sr, is produced in this decay process and was produced in rounds of stellar nucleosynthesis predating the creation of the Solar System.
Different minerals in a given geologic setting can acquire distinctly different ratios of radiogenic strontium-87 to naturally occurring strontium-86 (Sr as the parent melt.
The dates indicate the true age of the minerals only if the rocks have not been subsequently altered.
The important concept in isotopic tracing is that Sr derived from any mineral through weathering reactions will have the same Sr as the mineral.