Besides these two a number of other absolute method like thermo luminescence, dendrochronology, Electron Spin Resonance etc.also proved very helpful for dating various events of the past.Carbon dating discovered in 1955, proved very helpful for establishing absolute dating in various archaeological sites.
The method requires sufficient uranium to produce a track density, which can be counted within reasonable time.
Amino Acid Racemisation, a method of absolute dating applied to human fossils is developed very recently.
This is based on the fact that all living organisms have L-amino acid in their protein and after death, and over a long period of time all the L-amino acids except glycine undergo change called racemisation and became non protein D-amino acid.
the 'fossil' tracks counted) viz., exposes the sample to a known number of low energy (thermal)neutrons which induce fission of a small fraction of the uranium atoms in the sample.
The sample is immersed in the proper chemical reagent, which allows rapid attack of the narrow regions of damage and slower dissolution of the adjacent unchanged material.