Fission tracks are tiny microscopic damage marks recorded within certain minerals when spontaneous fission of uranium-238 occurs.
It is one of the most important methods in thermochronology.
A uranium-238 atom can spontaneously split into two highly energetic fragments. This process leaves a tiny linear “mark” in the mineral’s crystal structure, and these marks are fission tracks.
Simplified:
A uranium atom splits → The fragments pass through the crystal → They damage the crystal lattice → A permanent microscopic trace remains
The traces are mainly studied in minerals such as:
The number and length of the traces allow us to calculate:
In the laboratory:
Using this data, the age and thermal history of the sample are calculated.