A trail of damage left in a sample of rock or mineral by charged atomic particles. The particles (atomic nuclei) that produce these tracks are either the spontaneous fission fragments of radioactive nuclei within the sample or cosmic rays. The age of a rock sample such as a meteorite may be calculated by counting the number of fission tracks; this is known as fission-track dating. See also Exposure Age.
Subjects: Astronomy and Astrophysics.