Geology and lithic procurement in Upper Palaeolithic Europe: a weights-of-evidence based GIS model of lithic resource potential

In this paper we examine ways to predict the distribution of siliceous rock in Europe, using a Bayesian technique known as 'Weights-of-Evidence'. We use the technique to classify bedrock geological formations in terms of their likelihood of yielding tool-quality lithic raw materials, and we use the results to re-examine possible causes of a west-east cline in maximum lithic raw material transfer distances observed when comparing sites in both Middle and Upper Palaeolithic Europe. It is evident from our results that there is a decline in abundance of geological formations highly predictive of tool-quality rock along a west-east cline, predominantly reflecting a decrease in abundance of Jurassic and Cretaceous chert-bearing sedimentaries. Our results are consistent with an interpretation of the Upper Palaeolithic record of transfer distances as indicating special-purpose procurement.