However, the natural abundance of a given isotope is also affected by the probability of its creation in nucleosynthesis ( as in the case of samarium; radioactive 147 Sm and 148 Sm are much more abundant than stable 144 Sm ) and by production of a given isotope as a daughter of natural radioactive isotopes ( as in the case of radiogenic isotopes of lead ).
32.
The ratios D + \ Delta { P } _ t \ over D _ i ( relative concentration of daughter and non-radiogenic isotopes ) and { P-\ Delta { P } _ t \ over D _ i } ( relative concentration of parent and non-radiogenic isotope ) are measured by mass spectrometry and plotted against each other in a three-isotope plot known as an " isochron plot ".
33.
The ratios D + \ Delta { P } _ t \ over D _ i ( relative concentration of daughter and non-radiogenic isotopes ) and { P-\ Delta { P } _ t \ over D _ i } ( relative concentration of parent and non-radiogenic isotope ) are measured by mass spectrometry and plotted against each other in a three-isotope plot known as an " isochron plot ".
