The cumulative flux of cosmic rays at a particular location can be affected by several factors, including elevation, geomagnetic latitude, the varying intensity of the Earth's magnetic field, solar winds, and atmospheric shielding due to air pressure variations.
Rates of nuclide production must be estimated in order to date a rock sample.
By the time the cosmic ray cascade reaches the surface of Earth it is primarily composed of neutrons.
When one of these particles strikes an atom it can dislodge one or more protons and/or neutrons from that atom, producing a different element or a different isotope of the original element.
These rates are usually estimated empirically by comparing the concentration of nuclides produced in samples whose ages have been dated by other means, such as radiocarbon dating, thermoluminescence, or optically stimulated luminescence.
Surface exposure dating is a collection of geochronological techniques for estimating the length of time that a rock has been exposed at or near Earth's surface.
Surface exposure dating is used to date glacial advances and retreats, erosion history, lava flows, meteorite impacts, rock slides, fault scarps, and other geological events.