Studies of strata, the layering of rocks and earth, gave naturalists an appreciation that Earth may have been through many changes during its existence.These layers often contained fossilized remains of unknown creatures, leading some to interpret a progression of organisms from layer to layer.material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.
A method for determining the age of an object based on the concentration of a particular radioactive isotope contained within it.
The amount of the isotope in the object is compared to the amount of the isotope's decay products.
giving an age for the Solar System and an upper limit for the age of Earth.
It is hypothesised that the accretion of Earth began soon after the formation of the calcium-aluminium-rich inclusions and the meteorites.
For inorganic matter and for older materials, isotopes of other elements, such as potassium, uranium, and strontium, are used.
Mikhail Marov of the Vernadsky Institute of Geochemistry and Analytical Chemistry said scientists had determined the meteorite's age by observing the amount of radioactive isotopes and their decay byproducts, a technique called of a granodiorite at the Cuttaburra A prospect indicates that this mineralised system may be Middle Silurian in age and thus indicating that the host rocks are older than those hosting the Cobar-type deposits.
It has become increasingly clear that these radiometric dating techniques agree with each other and as a whole, present a coherent picture in which the Earth was created a very long time ago.
Further evidence comes from the complete agreement between radiometric dates and other dating methods such as counting tree rings or glacier ice core layers.
Because the exact amount of time this accretion process took is not yet known, and the predictions from different accretion models range from a few million up to about 100 million years, the exact age of Earth is difficult to determine.