The integration of chronological and archaeological information to date building construction: an example from Shetland,Scotland, UK

This paper presents new chronological data applied to the problem of providing a date for the construction of a prehistoric building, with a case study from the Old Scatness Broch, Shetland. The innovative methodology employed utilises the combination of radiocarbon and optically stimulated luminescence (OSL) dates with the archaeological information, which includes the stratigraphic relationships of sampled deposits, context information, and evidence relating to the formation of the deposit. This paper discusses the scientific validity of the dates produced, and the advantages that the methodology employed at this site offers for archaeological interpretation. The combined dating evidence suggests that the broch at Old Scatness is earlier than the conventionally accepted dates for broch construction. More broadly it shows the value of integration of the specialists at the planning stages of the excavation. The application of a Bayesian statistical model to the sequences of dates allowed investigation of the robustness of the dates within the stratigraphic sequences, as well as increasing the resolution of the resulting chronology. In addition, the value of utilising multiple dating techniques on the same deposit was demonstrated, as this allowed different dated events to be directly compared as well as issues relating to the formation of the sampled deposit. This in turn impacted on the chronological significance of the resulting dating evidence, and therefore the confidence that could be placed in the results.     

Palaeoenvironments, the archaeological record and cereal pollen detection at Clickimin, Shetland, Scotland

The Loch of Clickimin, Shetland, is well known for its broch and associated monuments supposedly of the Bronze and Iron Ages, although the former date is disputed. Pollen, diatom and sedimentological investigations permit fresh insights into the landscape and economic impacts of those who constructed the monuments, reveal that the environs of the site experienced environmental change from Neolithic times onward and provide the first Holocene radiocarbon dates from the immediate locality. The broch-building period witnessed a continuation of pre-existing pastoral husbandry for which heather burning may have exacerbated the natural spread of blanket peat. Initially, no evidence was adduced for local arable activity in the present investigation, and this was thought to be consistent possibly with the low numbers of excavated querns and the absence of cereal macrofossil finds when compared with other Shetland broch sites. The application of ‘rapid scanning’ techniques, however, led to the discovery of a consistent cereal-type pollen representation from Bronze Age times onwards. The discrepancies between the palaeoenvironmental evidence and the environmental and palaeoeconomic inferences made by the excavator of the site are explored. Evidence is presented that both supports and contradicts previous assumptions surrounding an important archaeological site.