By determining the number of tracks present on a polished surface of a grain and the amount of uranium present in the grain, it is possible to calculate how long it took to produce the number of tracks preserved.
As long as the mineral has remained cool, near the earth surface, the tracks will accumulate.
This method dates the formation or time of crystallisation of the mineral that is being dated; it does not tell when the elements themselves were formed.
It is best used with rocks that contain minerals that crystallised over a very short period, possibly at the same time the rock was formed.
Zircons will loose their tracks at higher temperatures of 200.
The tracks will then begin to accumulate when the rock begins to cool.
Geological Time | Geologic Time Scale | Plate Tectonics | Radiometric Dating | Deep Time | Geological History of New Zealand | Radiometric Dating Radiometric measurements of time Since the early twentieth century scientists have found ways to accurately measure geological time.
The discovery of by the French physicist, Henri Becquerel, in 1896 paved the way of measuring absolute time.
The New Zealand physicist Ernest Rutherford, suggested in 1905 that the exact age of a rock could be measured by means of radioactivity.
For the first time he was able to exactly measure the age of a uranium mineral.