MICROPETROGRAPHIC ANALYSIS AS A TOOL FOR PROVENANCE STUDIES OF LIMESTONE USED IN PREHISTORY AND ANTIQUITY OF ISTRIA, CROATIA (original) (raw)

The westernmost region of the Republic of Croatia – the Istrian peninsula – is characterized by predominantly carbonate surface deposits of Jurassic, Cretaceous and Paleogene age, as well as by terra rossa and alluvium deposits of Quaternary age. The carbonate deposits of Istria – limestones and dolomites – are of relatively high quality and have been exploited since prehistory. During prehistory stone was extracted from the very tops and slopes of the hills or in the immediate vicinity of the settlement for the construction of the ramparts of hillforts (Buršić Matijašić 2008). The local limestone sources were also used for funerary practices during the Bronze Age: the deceased was laid in a stone casket made from limestone slabs which was then covered with a stone pile (Codacci-Terlević 2004). On the other hand, during Antiquity limestone was extracted in a more systematic way in the shape of regular blocks (Parica 2014). We sampled several prehistoric and Roman sites in Istria as well as several outcrops or quarries in an attempt to discover the limestone sources for the sampled sites. Along with the macroscopic descriptions in the field, we also conducted a micropetrographic analysis of the samples which allowed us, to an extent, to identify the type and geological age of raw material used for an activity. The aim of the micropetrographic analysis is to identify the composition of the samples (skeletal and non-skeletal components of rock, together with the binding material), its fabric (arrangement of all constituents within a rock) and diagenetic changes (processes occurring within the sediment after its deposition) and classify the samples after Folk (1959, 1962) and Dunham (1962) with the modifications after Embry and Klovan (1972). We will present the sampled sites, outcrops and quarries and the results of the micropetrographic analysis. However, micropetrographic analysis beside obvious advantages has some shortcomings, and its results are not always enough for answering specific archaeological questions.