Now lead and uranium are particularly susceptible to such shuffling in the event of even mild metamorphism.
As the uranium decays, subatomic particles split away – this process is called fission.
These particles leave tiny tracks in the crystal structure of the zircon, which geologists count using a powerful microscope.
Fission tracks are most often caused by the spontaneous fission of the parent Uranium-238 atom into two daughter atoms of palladium-119.
, which is actually a number measuring the total number of fissions per year (Geochronology Group 2005).
The two fragments are propelled in opposite directions from the reaction site, dissipating their considerable excess kinetic energy in the host crystal lattice.
This interaction disrupts the crystal structure creating a single linear damage trail at the atomic scale.Fission track dating is somewhat of an anomaly in the field of radiometric dating.All other radiometric dating techniques rely on the relative abundances of a known parent isotope of an element and its corresponding concentration of daughter decay products.(removal of material by solution) of the host substance with a suitable chemical reagent; the leaching process allows the etched fission-track pits to be viewed and counted under an ordinary optical microscope.The amount of uranium present can be determined by irradiation to produce thermal fission of .Fission track dating is a radiometric method of age determination based on the accumulation within insulating solids of damage trails formed by the spontaneous nuclear fission decay of the uranium isotope U nucleus is α-particle emission; however, about one in every two million decays is by nuclear fission.