As illustrated in figure 1, this point defines the lower (left) end of the isochron.
Therefore, troilite found in Canyon Diablo represents the primeval lead isotope composition of the solar system, dating back to 4.55 /- 0.07 Byr.
Therefore, the most precise dating method for these meteorites is the Pb–Pb method, which allows a correction for common Pb.
Pb is relatively low, this isotope has larger measurement errors than the other Pb isotopes, leading to very strong correlation of errors between the measured ratios.
Successive collisions between accreted bodies led to the formation of larger and larger planetesimals, finally forming the Earth–Moon system in a giant impact event.