palaeolithic

5.2.3 Dietary Reconstruction and Population Movements

Stable isotopes

Stable isotopes have a number of uses in archaeology. The concentrations of C-, N- and S-isotopes in human bone collagen can provide basic information on diet, such as the relative importance of terrestrial versus aquatic food sources. In practice, however, applications of dietary tracing using stable isotopes in the Scottish Mesolithic have been severely limited by the scarcity of human remains. No formal burials are known from Mesolithic sites, and the only dietary stable isotope results available are for disarticulated human remains from shell middens on the Isle of Oronsay (Richards and Mellars 1998; Richards and Sheridan 2000; Milner and Craig 2009). Sr- and O-isotopes in human bone/teeth can be used as tracers of population movement, but again Mesolithic applications in Scotland are constrained by the lack of human remains. O-isotope analysis can also be used to investigate the season of exploitation of fish and shellfish found in archaeological sites. While there have been some notable applications at Mesolithic sites around the Atlantic and Mediterranean coasts of Europe (e.g. Mannino et al. 2003; Colonese et al. 2009), the technique has hardly been used at all in Scotland (in spite of the abundance of suitable material); instead seasonality studies have relied on growth-line analysis of cockle shells (Deith 1983) or metrical analysis of fish otoliths (Mellars and Wilkinson 1980).

5.2.2 Artefact studies

Experimental work under way to examine the processing of hide and associated wear on tools © Caroline Wickham-Jones

Since the 1960s micro-wear analysis has been the standard technique for investigating the ways in which tools made from stone, bone, and shell were used in the past. However, after an initial burst of interest (e.g. Hope 1981), archaeologists and funding bodies in Scotland have been slow to adopt this technique, which is all the more surprising given that lithic artefacts are all that survive on many Mesolithic sites, and the few recorded Mesolithic shell middens provide some of the best evidence of bone tool manufacturing and use from this period in the British Isles. Bill Finlayson’s pioneering studies of lithic assemblages from SW Scotland and Islay were aimed primarily at inferring the uses of microliths, and remain the most extensive published microwear studies of chipped stone artefacts from Scottish Mesolithic sites (Finlayson 1990; Finlayson and Mithen 2000; see also Hardy 2004). Only two studies of microwear traces on Mesolithic bone tools have been published to date (Griffiths and Bonsall 2001; Hardy 2009). Both studies focused on bevel-ended tools from shell middens on the west coast and were informed by experimental work, but reached somewhat different conclusions. The study by Hardy is notable for its use of scanning electron microscopy (SEM).

Experimental approaches have also been used to analyse the macro-wear patterns on coarse stone tools. Barlow and Mithen (2000) used elongated pebble tools for flint knapping, hide preparation, and limpet removal and compared the fracture and macro-wear patterns to those coming from Mesolithic coarse stone tools from Bolsay (Islay) and Staosnaig (Colonsay). From this they concluded that ‘limpet hammers’ had indeed most likely been used for removing limpets, although wear patterns relating to hide preparation were also evident on artefacts from Staosnaig.

A complementary method of functional analysis involves the study of physical (organic and/or mineral) residues on the surfaces of tools. So far, only one such study has been published for the Scottish Mesolithic, that by Hardy (2009) who examined bevel-ended tools from Sand and Loch a’Sguirr using SEM, although the results for both mineral and organic residues proved difficult to interpret.

Collecting nodules of Rum Bloodstone ©Caroline Wickham-Jones

Another important aspect of the study of stone tools is the sourcing (provenancing or characterization) of the materials used in their manufacture. A variety of archaeometric techniques are available to study the procurement of lithic materials, including geochemical ‘fingerprinting’. Williams Thorpe and Thorpe (1984) used this technique to investigate the sources of pitchstone exploited during the Mesolithic to Bronze Age in Scotland and northern England. Successful characterisation of pitchstone artefacts is possible because there are relatively restricted sources (Ballin 2009). The challenge for archaeologists/geologists will be to extend this research to other lithic materials (e.g. flint, chert, bloodstone, baked mudstone, chalcedony, etc.), some of which were used more widely than pitchstone during the Mesolithic.