The most common of these dating techniques is Cosmogenic radionuclide dating.
Earth is constantly bombarded with primary cosmic rays, high energy charged particles — mostly protons and alpha particles.
By sampling the rocks and separating certain minerals (such as quartz or pyroxene) and calculating the amount of these minerals (as a ratio to other, stable, minerals), we can work out how long the rock has been exposed on the earth’s surface.
Cosmogenic nuclides are rare nuclides that form in surface rocks because of bombardment by high-energy cosmic rays.
It is most useful for rocks which have been exposed for between 10 years and 30,000,000 years.These particles interact with atoms in atmospheric gases, producing a cascade of secondary particles that may in turn interact and reduce their energies in many reactions as they pass through the atmosphere.By the time the cosmic ray cascade reaches the surface of Earth it is primarily composed of neutrons.It is an excellent way of directly dating glaciated regions.It is particularly useful in Antarctica, because of a number of factors: Cosmogenic nuclide dating is effective over short to long timescales (1,000-10,000,000 years), depending on which isotope you are dating.