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Guidance on sampling for cosmogenic surface exposure-age dating

Anyone collecting rock samples in Scotland has a responsibility to ensure that their work is carried out in a responsible way, even in areas that do not have statutory designation or other conservation protection. The main issues concern permissions for access and sampling, choice of sampling location and avoiding unsightly visual impact of conspicuous fresh scars, particularly on lichen or moss-covered rock or rock with a surface weathering patina.

General

  • Before visiting a site, ask for permission to take samples from the landowner, and if it is a National Nature Reserve or a designated conservation site, you may also need to get a permit to collect samples. See the Scottish Ethical Rock Collection Policy regarding access and permissions.
  • As far as possible, choose sampling sites located away from footpaths or that are not readily visible.
  • Avoid iconic boulders or those that have historical or cultural associations (e.g. these may have local names such as 'Rob Roy's Putting Stone').
  • In areas of archaeological interest, seek appropriate professional advice and if necessary have an archaeologist on-site when sampling.
  • If in doubt, do not sample before seeking further advice (e.g. from a local museum or archaeologist).
  • Do not mark boulders with paint.
  • Take only the minimum amount of rock required for a viable sample.
  • Do not leave surfaces obviously damaged.
  • Clean up loose rock chippings.
  • Allow sufficient time on-site to mitigate the visual impact after sampling.

Sampling procedures

The recommended approach is to use a hammer and chisel, exploiting natural edges, joints and fractures to facilitate removal of material.

If use of a rock saw or drill is necessary to obtain a viable sample, and alternative boulders are not available where a hammer and chisel can be used (e.g. on glacially smoothed boulders or bedrock with no visible weaknesses), then:

  • if possible, cut at a shallow angle, or depth, and remove thin platy slivers;
  • break up any straight cut edges with a hammer and chisel to leave a shallow bevelled depression;
  • do not use cement or cement mixed with rock chippings to fill new holes because the material weathers out*.

*Note that in this respect this guidance differs from that for core hole restoration where plugging core holes is recommended.



Last updated on Friday 26th February 2016 at 14:50 PM. Click here to comment on this page