Glacial geologists use this phenomenon to date glacial landforms, such as erratics or glacially transported boulders on moraines or glacially eroded bedrock.Dating glacial landforms helps scientists understand past ice-sheet extent and rates of ice-sheet recession.(See Paul Bierson's guidelines for the Cosmogenic Nuclide Extraction Lab at the University of Vermont for a detailed description of sample preparation techniques for Be produced in situ also is increasingly being shown to also be useful for dating sediments in studies that examine basin-scale rates of denudation (Bierman et al., 1998).
Wherever we are on Earth, when we are outside, we are constantly bombarded by these cosmic rays.These cosmic rays do not penetrate deep into the earth’s surface.This is important for glacial geologists, as it means that surfaces that have had repeated glaciations with repeated periods of exposure to cosmic rays can still be dated, as long as they have had sufficient glacial erosion to remove any inherited signal.Different isotopes are used for different lengths of times.
This long period of applicability is an added advantage of cosmogenic nuclide dating.
The basic principle states that a rock on a moraine originated from underneath the glacier, where it was plucked and then transported subglacially.