Dating archaeological sites by seriation

• Finding a relative chronological order of sites is a common problem in archaeology. • Artifacts contained in sites characterize them and often help in their dating. • Seriation aims at ordering a set of units on the basis of types that correlate them. • Algorithms for seriation can treat large datasets, but produce approximate solutions. • An iterative refinement method may lead to improve the solution by a small effort. Seriation is an ordering problem which consists of determining the best ordering of a set of correlated units, whose relationship is defined by a bipartite graph. It has several applications in different fields, like genetics, anthropology, archaeology and psychology. Our application deals with the relative dating of archaeological sites based on the characteristics of parietal engravings found in them. Our interest lies mainly in the Domus the Janas , Neolithic burial sites typical of Sardinia, Italy. Two matrices, derived from the available data, give information about the similarity among the units. A well known seriation method is applied to them. Due to its formulation, the seriation algorithm employed produces in some cases a solution which does not appear to be completely satisfying. So we propose an approach to improve the quality of the solution, based on a quality indicator.