Terrestrial cosmogenic nuclide (TCN) dating methods are based on the in-situ accumulation of rare nuclides in rocks exposed to cosmic radiation. Although cosmic ray particles (principally neutrons) are strongly attenuated in the atmosphere, some reach the earth’s surface and interact with lithospheric nuclei within about a few meters of the Earth's surface to produce cosmogenic nuclides. Depending on the energy of cosmic ray particles and target elements in the rock, many new cosmogenic nuclides can be produced, such as Cl-36, Be-10, Al-26. When the production rates of these nuclides are known, their measured concentrations in rocks can be used to calculate how long these rocks have been exposed to the surface.
The main applications of cosmogenic nuclides include, but are not limited to, exposure dating of geological surfaces, burial dating, erosion and denudation rate determinations, constraining uplift rates, and rate of soil dynamics. Most of the applications of cosmogenic nuclides in Earth sciences are for surface exposure dating. In principle, any geological surface that is stable and continuously exposed to cosmic rays can be dated measuring the amount of accumulated cosmogenic nuclides in surficial rocks. The time elapsed since a geological event or process exposed a new surface or landform can be determined from the measured concentration of cosmogenic nuclides (i.e., giving the age of the surface).
Some examples of application fields of TCN method:
-fault scarps and tectonic off-set landforms
-bedrock erosion rates
-basin-wide erosion rates
-meteor impact craters