To constrain the timing of the retreat of this ice, we are using a technique known as cosmogenic nuclide dating.
Cosmic rays, originating from outer space, bring rare cosmogenic nuclide isotopes (I am using Aluminium) to the Earth’s surface, where they build up in exposed rock surfaces at known rates.
As 10-Beryllium and 26-Aluminium preferentially build up in quartz, the aim of the first week was to crush down the samples and extract as pure quartz as we could.
Firstly I had to crush the samples in the workshop to shards, and then grind them down on a disc miller.
Recent technical advances in both fields now allow the techniques to be used on timescales that are relevant to archaeology, and although technically challenging, both techniques are now capable of measuring sub-1,000 year ages.
For most human activities involving minerals and raw materials, the levels of exposure to these radionuclides are not significantly greater than normal background levels and are not of concern for radiation protection.
A blog of Dr Greg Balco of the Berkeley Geochronology Center in California has a very useful and up-to-date discussion of the issues associated with burial dating and its application ( accessed 15 July 2011).
Novel applications of multiple nuclides with different half-lives are also being developed for determining ages of timing and amounts of soil erosion in the past, with potential applications to archaeological settings (see below).
Technological developments in the last few decades have allowed more precise measurements of their concentration in terrestrial rock samples and this dating technique is becoming increasingly popular.
I collected the samples in the field in 20: Having collected the samples in the field and received funding to run them, I went up to the Scottish Universities Environmental Reserach Centre (SUERC) laboratories in East Kilbride to start the process!