The dating technique fluorine analysis
For the archaeologist and the prehistorian who deals with that long history of man, time is the most important consideration.The sequence of development of culture or the relationship between events that represent culture can be established only when events can be placed in proper time.Fission track dating is based upon the fact that over geological time spontaneous fission of uranium-238 impurities produces minute sub- microscopic damage trails in the most insulating solids, both long period of time.As the damage sites are permanent, a simple count of their number allows an age to be measured.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 proportion of these D-amino acids increases with time.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.
Third, the varves may form frequently rather than annually depending on the pattern of the melting.
The density of track depends on the uranium content as well as the age of the sample (i.e.
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 application of varve dating is restricted by several factors.
First, it is because varve accumulation occurs only to glacial areas of the world.