5. Discussion and Conclusion

IPG Group I, Ia and III axe thin-sections show sufficient petrographic variability to justify 24 sub-groups. These groupings were as a result of re-inspection of a large number of available thin-sections in a short period of time, possibly something that has not been done before. The variation in thin-sections, apart from the few that appear to have been wrongly classified, is slight and does not preclude a single large exposure as the source of material for the axes. However, the geology of Cornwall does not have a single large greenstone exposure; instead there are numerous smaller (km sized and smaller) exposures and although they share a common heritage, it is probable that several exposures provided material for Group I, Ia and III axes.

Examination of a few of the many greenstone sources did not reveal an exact match, but similarities were noted between samples from Mount's Bay (Penlee, Mousehole and Long Rock). Further sampling is recommended, as is a review of existing collections (e.g. Exeter University (ex-Camborne School of Mines)). The material that Mr D. Weddle discovered from pipe trenches in West Cornwall and which provides the closest match strongly supports (north-west?) Cornwall as the source for these axe groups. It is possible a more detailed geological survey may reveal heretofore unknown inland greenstone exposures or a trail of raw material from source to working site. It is improbable that a single exposure was the source of all IPG Group I (and Ia) axes.

Quantitative techniques were shown to have potential in cataloguing thin-sections, making it easier to assess assignment to axe groups. Further, this process, supported by microphotographs, provides the basis for improved recording of finds and could lead to a computerised mathematical probability-based process to allocate axe thin-sections to groups and exposures. Current image processing techniques could be used to automate the rudimentary scoring techniques described here. Further, computerised image analysis is a growing science and offers the potential to analyse and classify petrographic thin-sections rapidly.

PREVIOUS NEXT CONTENTS HOME