Relative dating methods in archaeology beeny's dating website
If you want to know the precise age of something, absolute dating techniques are the only option.They work by analysing the activity of elements and their decay over time.An element is defined by the number of protons in an atom’s nucleus.
These fossils are known as “index fossils” and include trilobites and ammonites.
Depending on the isotope, this can range from milliseconds to billions of years.
But the rate is constant, so as long as the original isotope is not replenished, the ratio of isotopes in a sample can tell you its age.
Any formations and fossils found within the middle layer are then, in theory, is younger than the layer below and older than the layer above.
Biostratigraphy takes this one step further, analysing the fossils found within each layer.