Samples of iron meteorite from Canyon Diablo (Meteor Crater) Arizona were found to have the least radiogenic composition of any material in the solar system.
The U/Pb ratio was so low that no radiogenic decay was detected in the isotopic composition.
The most accurate ages are produced by samples near the y-axis, which was achieved by step-wise leaching and analysis of the samples.
Previously, when applying the alternative Pb–Pb ischron diagram, the The result of U-corrected Pb–Pb dating has produced ages of 4567.35 ± 0.28 My for CAIs (A) and chondrules with ages between 4564.71 ± 0..32 ± 0.42 My (B and C) (see figure).
Patterson also analyzed terrestrial sediment collected from the ocean floor, which was believed to be representative of the Bulk Earth composition. Patterson to determine the age of the Earth in 1956.
Because the isotope composition of this sample plotted on the meteorite isochron, it suggested that earth had the same age and origin as meteorites, therefore solving the age of the Earth and giving rise to the name 'geochron'. Animation shows progressive growth over 4550 million years (Myr) of the lead isotope ratios for two stony meteorites (Nuevo Laredo and Forest City) from initial lead isotope ratios matching those of the Canyon Diablo iron meteorite.
This makes it difficult to determine the analytical uncertainty on the age.
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.This supports the idea that CAIs crystallization and chondrule formation occurred around the same time during the formation of the solar system.However, chondrules continued to form for approximately 3 My after CAIs.Lead–lead dating is a method for dating geological samples, normally based on 'whole-rock' samples of material such as granite.For most dating requirements it has been superseded by uranium–lead dating (U–Pb dating), but in certain specialized situations (such as dating meteorites and the age of the Earth) it is more important than U–Pb dating. As evident by the equation, initial Pb isotope ratios, as well as the age of the system are the two factors which determine the present day Pb isotope compositions.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.As planetesimals collided, various fragments were scattered and produced meteorites.Iron meteorites were identified as pieces of the core, while stony meteorites were segments of the mantle and crustal units of these various planetesimals.Your choice will depend on the material present in each rock. We have found this cliff and collected samples from the layers of sedimentary rocks.We know the oldest rocks are at the bottom and the youngest are at the top, but we want some actual dates. Drag and drop the rock sample from each layer onto the dating method you think will tell us its age.