Achaeometrical Research in Hungary II., 1988

ANALYSES - POTTERY - György SZAKMÁNY: Insight into the manufacturing technology and the workshops: evidence from petrographie study of ancient ceramics

György SZAKMÁN? INSIGHT INTO THE MANUFACTURING TECHNOLOGY AND THE WORKSHOPS: EVIDENCE FROM PETROGRAPHIC STUDY OF ANCIENT CERAMICS Abstract: Ancient ceramics from the Neolithic and Roman Periods have been studied using a pétrographie (polarising light) microscope. Optical and some mineralogical features, seen under the pétrographie microscope, have been used to characterise clasts and matrices of the ceramics. This method, a traditional technique in geological research, leads us to identifying minerals and rock fragments (used as tempering materials) and help determining source rocks and their possible locations. A careful structural-textural study of matrices of the ceramics provides significant information concerning ancient manufacturing technology and techniques applied in different workshops. Introduction The raw materials of the ancient ceramics are purely natural rocks and a mixture of minerals. During the firing procedure of these ceramics the original structural-textural features of the rocks, as well as the compositions and optical properties of most of the minerals did not change. Therefore, ceramics can be studied by traditional techniques in mineralogy and petrology such as pétrographie (polarising light) microscope and X-ray diffraction. Note that the same techniques have been equally used to determine changes in the structural-textural features of ceramics as well as in the optical properties of minerals and the identification of new phases formed during the firing. The raw material of ceramics contain quantities of clay mixed with tempering materials. This clay forms the majority of the matrix in ceramics. Approximately 5-20% clasts (mineral and rock fragments) can also be found as tempering material in the matrix. Usually, the clasts are larger than Юцт in size. This size of clasts can be unambiguously recognised under the pétrographie microscope,. Recently, a great number of samples from Roman amphoras and some Roman lamps from Szőny as well as Neolithic potsherds from Bicske-Galagonyás have been studied. The details and results of these investigations were reported in papers by JÓZSA and SZAKMÁNY 1987; WEISZBURG and PAPP 1987; JÓZSA et al. 1994; SZAKMÁNY 1996. In this paper, the technique used in my previous research of ancient ceramics is described. This paper also a contribution to our poor knowledge of ancient technologies used to make ceramics, because to date only a few papers have been published on subject (ILON 1996). Pétrographie microscope We have applied a pétrographie microscope to study the clasts, derived mainly from the tempering material in ceramics. To carry out this basic investigation, thin sectioning ceramics in 30um of thickness was necessary. The tempering material typically is siliciclastic rocks (mainly sand or sandstone) or fragments from any other rock (for instance, acidic igneous rocks, gneiss, schists and mafic-intermediate volcanic rocks, serpentinite, other metamorphic rocks and, in our samples, very often limestone). Some clasts that Department of Petrology and Geochemistry, Eötvös Loránd University, Múzeum körút 4/A, Budapest H1088, Hungary 77