Autor: Natali Neral
After completing my graduate study in geology at the Faculty of Science, University of Zagreb, I am employed as an assistant at the Institute of Archaeology, on the research project of the Croatian Science Foundation (prePOT, UIP-2020-02-3637, http://prepot.iarh.hr/index.php/en/) The project represents the first systematized research of pottery, raw materials, and technological choices in Croatia based on connecting different scientific fields (archaeology and geology). As part of that, under the mentorship of the project manager, Ph.D. Andreja Kudelić (Institute of Archaeology) and associate professor Ph.D. Ana Maričić (Faculty of Mining, Geology and Petroleum Engineering), I enrolled in postgraduate study at the Faculty of Mining, Geology and Petroleum, University of Zagreb. The doctoral research is focused on the pottery raw materials and pottery technology through different periods of the past in Croatia. The research is conducted on archaeological ceramics (pottery) from multi-period archaeological sites (from the Neolithic to the Late Mediaeval period, figure 1) and on pottery raw materials (clay and tempers) collected in the vicinity of the sites (figure 2). The research includes four case studies; Eastern Croatia, Central Croatia, Istria and Northern Adriatic and Central Dalmatia located in different geological settings whereas in the archaeological context, the areas are under different cultural influences. The research aims to determine the type, properties, and provenience of the pottery raw materials and the characteristics of the technological process by applying different analytical methods. These objectives enable an understanding of the variabilities in the choice of the raw materials and pottery technology within communities from different periods of the past.
Figure 1. Pottery sherds from multiperiod site Jagodnjak-Krčevine in Baranja region. Pottery from (a, b) the Neolithic, (c, d) the Bronze Age, (e, f) the Late Iron Age, (g, h) the Roman period and (i, j) the Mediaeval (from Neral et al., 2023).
Figure 2. Clayey material suitable for making pottery from (a) Istria and (b) Baranja. (c) Calcite and (d) different types of fragmented rocks that potters intentionally add to the clay during the paste preparation.
In archaeological science, pottery (ceramic vessels) represents the most numerous sets of findings found on sites during almost all periods of human history. It is the main and often the only remnant of the material culture that constitutes the essential evidence for interpreting ancient human history. The study of pottery in the context of material science, therefore starts from the analysis of the raw materials but also examines each segment of the production process which enables a wide range of scientifically based data that consider the technology of the ancient communities. In such research, it is necessary to apply different analytical methods that enable the determination of the mineralogical-petrographic and geochemical composition of ceramics and pottery raw materials, as well as the determination of the characteristics of technological process.
The basic analytical method used in my research is optical microscopy of thin sections (ceramic petrography, figure 3) which permits collecting data regarding the mineralogical and petrographic composition of ceramics, clay paste preparation (paste recipe), and estimating the firing temperatures (Quinn 2013; Quinn 2022). X-ray powder diffraction provides the mineralogical composition and the estimated firing temperature of ceramics through the mineral phases present in a specific temperature range. Various geochemical methods are used to investigate the provenience of pottery raw materials. Such research is carried out using the comparative method of archaeological material and potential raw materials from the vicinity of the sites. The most frequently used geochemical methods (ICP-ES, -MS, -OES) are destructive methods performed on the homogenized powdered ceramics samples, leading to the loss of data on certain raw materials (clay and tempering materials). For this reason, I supplemented the already used ICP-ES and ICP-MS methods with the application of non-destructive methods (SEM-EDS and p-XRF) which enable precise determination of the geochemical composition of individual pottery raw materials. I applied SEM-EDS and p-XRF on ceramic samples at the University College London as part of the competition of the Croatian Science Foundation "Mobility Program - outgoing mobility of assistants (MOBDOK-2023)". The first part of the scientific research training was related to the application of p-XRF on ceramics, while the second part was devoted to work on SEM-EDS (figure 4). I also gained valuable experience through pleasant cooperation with the host-mentor and expert in the analysis of ceramics, Ph.D. Patrick Quinn.
Figure 3. Thin section microphotographs of ceramic samples (XPL). Ceramic sherds are composed of clayey material and intentionally added tempering materials such as (a) various metamorphic rocks, (b) calcite, (c) mollusc shells and (d) grog (modified after Neral et al., 2024, in press).
Figure 4. SEM-EDS in the Wolfson Archaeological Science Laboratory at the University College London.
Application of the aforementioned analytical methods enables the reconstruction of the technological process of pottery production and an insight into the types and origin of the materials used in the past. My doctoral research thus contributes to the understanding of the variability in the choice of raw materials and pottery technology, as well as to the consideration of dynamics of landscape use through a broad spatiotemporal context, i.e. in different areas and within cultural groups from different periods of the past in Croatia.
References:
Neral, N., Kudelić, A., Maričić, A., Mileusnić, M. (2023). Pottery technology through time: Archaeometry of pottery and clayey raw material from the multi- period site in eastern Croatia. Rudarsko-geološko-naftni zbornik, 38, 63, 1-21. DOI: 10.17794/rgn.2023.2.1
Neral., N., Kudelić, A., Maričić, A., Mileusnić, M. (2024). Tracing the origin of raw materials used for the production of ancient ceramics: Case study of multi-period archaeological sites (Continental Croatia). Geologia Croatica, in press
Quinn P. S. (2013). Ceramic Petrography: The Interpretation of Archaeological Pottery & Related Artefacts in Thin Section. Archaeopress. Oxford. 260 p.
Quinn, P. S. (2022). Thin Section Petrography, Geochemistry and Scanning Electron Microscopy of Archaeological Ceramics. Archeopress. 466 p.