X-ray computed microtomography of Late Copper Age decorated bowls with cross-shaped foots from central Slovenia and the Trieste Karst (North-Eastern Italy): technology and paste characterisation

Abstract

About 20 Late Copper Age bowls with cross-shaped foots from Deschmann’s pile dwellings (Ljubljansko barje, central Slovenia) and Trieste Karst (North-Eastern Italy) have been investigated using X-ray computed microtomography (microCT) in order to study the vessel-forming technique, to characterise their pastes and to test the hypothesis that some Karst bowls could have been imported from nowadays central Slovenia or even more distant regions. In three selected virtual slices per sample, clay, lithic inclusions and pores have been segmented and quantified. In addition, the area, maximum length and width of each lithic inclusion have been calculated. Then, the microCT-derived results have been statistically analysed by principal component analysis (PCA). The orientation of pores and disjunctions in microCT volumes show that the basins of the bowls were built using mainly the coiling technique, while the base was shaped starting from a central piece, to which a layer of clay was added and then reshaped in order to produce the foots. The Slovenian bowls include both medium/coarse-grained and very fine- or fine-grained vessels mainly tempered with carbonate inclusions. The pastes of the Karst bowls are considerably heterogeneous. One bowl was most likely imported to the Karst but not from central Slovenia as it shows peculiar components, shape and decoration. The other two imported vessels show a very fine-grained paste comparable to the one of several samples from Deschmann’s pile dwellings. Such technological similarity is confirmed by PCA of microCT data and petrographic observations. Our study confirms the existence of strong cultural connections between central Slovenia and the northernmost Adriatic coast during the Late Copper Age.