Cosmogenic Nuclide Techniques

In the Schaefer Cosmo Lab we develop and refine terrestrial cosmogenic nuclides as chronometers and tracers in the Earth Sciences that will tell us about processes (glaciation, erosion, etc.) that have shaped the surface of our planet over millions of years. Cosmogenic nuclide dating is a method of surface exposure dating to measure the exposure age of a boulder at the Earth's surface over long timescales. This method is used to date rocks on the Earth's surface that have been exposed to cosmic radiation. Once the moraine is exposed to the atmosphere, it will accumulate cosmogenic nuclides, which are rare nuclides that are formed in surface rocks when interacted with high-energy cosmic rays that are from supernova explosions of stars in space. Cosmic rays do not penetrate the Earth's surface, which is why we use them in our lab to determine the age of surface exposure to date glacial landforms. Examples of the most common nuclides are ¹⁰Be, ¹⁴C, ²⁶Al, ³⁶Cl, and stable noble gases (³He and ²¹Ne). In our lab we focus on the extraction of Beryllium-10 (¹⁰Be) from quartz. We focus on quartz due to the large prevalence of quartz in Earth’s crust (Eaves, 2018). By measuring cosmogenic nuclide concentrations we find the exposure age, which ultimately improves our understanding of climate and sea level change, extreme climatic events, landscape evolution, and glacial geomorphology.

To read more about our specific techniques check out the documents below:

Extraction of Beryllium from Quartz and Separation and Purification of Quartz from Whole Rock