Is It Visible? Micro-Artefacts' Non-Linear Structure and Natural Formation Processes

Abstract

Micro-artefacts (i.e., cultural particles smaller than 2 mm in diameter), due to their abundance and incorporation in an archaeological deposit constitute a significant part of the cultural particles present, and their analysis can assist the archaeological interpretation (Stein, 1987). The analysis of micro-artefacts is extensively complex due to the different micro-artefact categories that may appear in an archaeological context and also because of the number of different cultural (and natural) formation processes that may have been involved in the creation of characteristics specific to an archaeological context. Recently, a non-linear data analysis technique (S-SOFM) was applied on micro-artefact data. The technique revealed hidden structures among the data that linear methods were unable to classify and also offered an additional way to unfold cultural information encoded within them (i.e., micro-artefacts), and thereby, observe the dynamics of cultural factors in site formation processes (Kontogiorgos et al., 2007). The spherical self-organizing feature map method was implemented in this study to perform the initial pattern searching operation in a sample of 4-dimensional micro-artefact data shaped only by the effects of natural formation processes (hereafter: N.F.P.), and so further explore the developed visualization tool as a means to identify patterns in micro-artefacts prior to their detailed analysis. An example is given on micro-artefact data from the colluvial deposit, covering the theatre of the Hellenistic period, located outside the city walls of the Hellenistic city of Gitana in the Thesprotia region-Epirus-NW Greece (Kontogiorgos and Preka, 2009). Section 2 briefly describes how the spherical self-organizing map creates a 3D visual or graphical representation of the data. Section 3 applies the method on a sample of 4-dimensional microartefact data. General findings and concluding remarks are presented in Section 4.