Archaeometrical analysis of Neolithic pottery and comparison to potential sources of raw materials in their immediate environment

Pottery production is one of the most important crafts of prehistoric communities. Most of the archaeological evidence recovered from excavations consist of sherds and different ceramics, found on habitation sites as well as cemeteries. Pottery therefore has served for long as basic starting point of archaeological analysis of a site. Recent archaeometrical research added new dimensions to the study of archaeological pottery by focusing on material as well as form of vessels.

So far, we are on the level of basic research: describing petrographical characteristics, technological types, assessing firing temperatures and making efforts for regional fingerprinting of pottery on the basis of its material.

Material characteristics of the ceramics may depend on many complex factors: technological, regional, cultural and functional factors. Our proposed project intends to deal mainly with regional factors comparing local sediments with the material of early ceramics all over Hungary. Hungary is known to serve as a secondary centre for Neolithisation in Europe, forwarding ideas and perhaps also immigrants from the Southern parts of Europe, bringing along, apart from the knowledge of making ceramics, notions on food production, agriculture, animal husbandry and permanent settlements. These notions were quickly adopted and forwarded towards the west and the north.

Considerable pioneering work has been done by members of the research group already. The present proposal could facilitate the exchange of ideas and ensure a homogeneity of analyses by the help of which we could make better founded statements concerning the provenance and technology of early pottery.

Ceramics consist of two main components: plastic clay (matrix) and aplastic inclusions or temper (sand, small rock fragments, etc.). In many cases pottery also contains small pores. Depending on the size of the temper, fine (the size of temper is smaller than 0.2 mm) and coarse (the size of temper is bigger than 0.2 mm) wares can be distinguished.

Provenance studies on ceramics can focus either on the aplastic inclusions or on the whole material of the sherd.

The most basic analytical method used in provenance studies on ceramics is a petrographic investigation focusing on the identification of aplastic inclusions. The quality (mineral and/or rock fragments), quantity (distribution and amount of the fragments) and other physical properties (e.g. roundness, sphericity) of the temper can provide information which, compared to the geological data from the presumed region of origin of the ceramics, can decide about their identification.

In a first step the qualitative analyses provides an insight into the geology of the area where the vessel was produced. Comparing these data with other microscopic observations (e.g. quantitative analyses of the temper, textural features, etc.) provides relatively clear insight into the geological/geographic features of the potential production sites.

As a second step the data have to be compared with geological-petrographic data from the assumed habitat of the sherd and with other, locally produced ceramics.

Petrographic investigations are principally successful in case of medium-coarse and coarse wares.

Although microscopic observation is an essential method in archaeometric research of ceramics, in several cases this sole method cannot provide decisive information about the origin of the vessel. Chemical analyses, combined with petrographic data, can be a useful, complimentary, analytical technique in identification the origin of pottery.

Several chemical methods have been successfully used in the last years in research on the provenance analyses of ceramics (e.g. X-ray fluorescence anlysis (XRF), Instrumental Neutron Activation Analysis (INAA), etc.). The applied methodology is similar to petrographical evaluation: data have to be compared to databases (either to locally produced ceramics (e.g. misfired vessels, rest of kilns, etc.), or to local sediments (clays, sands, fluviatile mud, loess, etc.)). The chemical methods have been proved useful especially for researching the origin of fine pottery.

Attention has to be paid to the fact that, in most cases, chemical composition of a sherd is not only influenced by the chemistry of the clay or mud, but also by other factors (e.g. different chemistry of temper, mixing of different clays, secondary processes, firing, etc.). In order to filter and understand these phenomena, especially at coarse wares, combined use of petrographic and chemical analyses is necessary.

Chemical analyses focus on the elementary (major and trace elements) composition of the whole sherd, which provide a "mixed" chemical signal of the clay and aplastic inclusions (rock and mineral fragments). Depending on the quantity and elementary composition of these aplastic clasts, the chemical signal of the sherd may be so strongly influenced, that notwithstanding local production of the vessel, chemical signal does not fit the chemical pattern of local sediments (clays). In order to avoid such problems, chemical investigation of single rock and/or mineral fragments (Electron Microprobe Analysis) can be applied. The benefits of this method are that it can be carried out on the same thin section used for petrographic observations, little material is needed for the analysis, and the method allows for a direct comparison to the geological data of the rocks and minerals found in surrounding areas of the supposed place of origin of the pottery.