Fission Track Technique - This technique dates material ranging from 20 years to 1,000,000,000 years before the present.
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.
Third, the varves may form frequently rather than annually depending on the pattern of the melting.
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.
Chronology, the study of events in time frame, is hence the central theme of archaeologist, like the geologist who deals with the story of earth history.
According to the Dictionary of Anthropology, the word chronology means the science of computing dates or treaties showing arrangement of events with dates.
In other words, Chronology is the arrangement of events, or the materials which represent them, in the order of their occurrence in time.
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.The proportion of these D-amino acids increases with time.Thus the age of the skeletal materials that are found in archaeological sites can be estimated by determining the amount of change, racemisation that has occurred.As the damage sites are permanent, a simple count of their number allows an age to be measured.The density of track depends on the uranium content as well as the age of the sample (i.e.Amino Acid Racemisation, a method of absolute dating applied to human fossils is developed very recently.