Dating techniques used anthropology
Sir Flinders Petrie had worked out a formula for dating the finds on the basis of the thickness of the deposit.According to him a period of hundred years may be granted for the accumulation of a deposit of one and a half feet.
With the aid of these dated imports it was possible to date the associated Indian objects to the first two centuries A. Similarly NBP and PGW has helped in fixing the chronology of numerous sites. Sometimes dates are also obtained with the assistance of astronomy.At that time the radioactive disintegration takes over in an uncompensated manner. only half the C-14 will remain after the half-life period.In the disintegration process the Carbon-14 returns to nitrogen emitting a beta particle in the process.Astronomical data have been applied in the study of geological ice ages by calculating the curves for major fluctuation of solar radiation.Consequently, the chronology worked out for the geological deposits helped in dating the prehistoric tools found in these deposits. There are certain antiquities and potteries which by themselves have acquired a dating value.The quantity of the C-14 remaining is measured by counting the beta radiation emitted per minute per gram of material.
Modern C-14 emits about 15 counts per minute per gram, whereas Carbon-14 which is 5700 years old, emits about 7.5 counts per minute per gram.
In such cases subjective element cannot be ruled out.
But, for a single culture site the method is quite reliable.
The types and forms or shape of these pots and also the antiquities under go evolutionary changes in cource of time, It is further assumed that all living animals derive body material from the plant kingdom, and also exhibit the same proportion of C-14 material.
Therefore as soon as the organism dies no further radiocarbon is added.
The deposit thus occurring forms layers depending on the nature of the material brought in by the people inhabiting the area.