There are two types of TCNs, radioactive (‘radio-nuclides’) and stable.
The radio-nuclides, primarily , are extracted from exposed rocks and minerals, at several dedicated laboratories in Scotland.
There is obvious potential here for dating the emergence of Scottish coastal landscapes from below sea-level for subsequent occupation.
The SUERC Ar/Ar laboratory has three magnetic sector mass spectrometers which it operates for the NERC-funded national facility.As far as is currently known, TCNs have not yet been exploited directly in Scottish archaeological contexts, but there is great potential for their application, given the research capacity and analytical capability that are available in Scotland (see below).Surface exposure dating is widely used to provide ages of deglaciation for Scotland (e.g.Stroeven (1996) for the raised rock platforms of Lismore).TCNs can also be used to determine catchment-averaged rates of erosion, provided certain conditions can be met (Dunai 2010, 122).
Thus, geoarchaeological investigations could in principle include determination of catchment-averaged erosion rates, but it must be remembered that the rates so determined integrate the erosion rate for the time period it takes the material to get from 2m depth in the regolith/soil to the ground surface, where it is detached.
TCNs accumulate at the Earth’s surface and so provide a chronology of exposure (Siame 2008).
TCNs can also be used to determine rates of erosion, and multiple nuclides with different half-lives can be used to date the deep burial of materials (e.g., in caves where the materials are cut off from cosmic radiation).
In Israel, for example, Verri Be contents, indicating that the chert for these artefacts had been obtained from either deposits of varying depths (i.e., varying degrees of exposure to cosmic radiation) or from surface materials that had had varying durations of exposure at the ground surface.
In other words, TCN analysis in this context is a valuable tool for provenance studies and other specific applications may yet be developed.
For that reason, it is essential that anyone seeking to employ TCN analysis link up with a practising TCN analyst (or, at least, an experienced user).