The economic-cultural impact of the raw material clay for the brick city Luneburg

Luneburg, a city located in the North German Plain takes up an exceptional geological position. The salt deposits of the Upper Permian which underlying this region were folded to the surface by salt tectonics. Clayey raw material outcrops together with the salt dome in an exploitable amount. Clays and Marls from keuper, marine deposits like miocene mica clays as well as glacial till, glacio-lacustrine and glacio-fluviatil pleistocene and holocene sediments forming a widespread distribution of chemical and mineralogical sediment compositions. Due to the highly earned income of the saline in the middle age and the exploitable clay raw material  the city was able to afford to buy bricks for a lot of municipal buildings in spite of bricks were an expensive building material. Centurys afterwards Luneburg has the byname “brick city”.

Unidentified archaeological findings as well as dated and located pottery products, bricks and tiles will be analysed and compared to raw material from clay deposits of Luneburg and surroundings. By using multianalytical geoscientific investigations the relationship between the local clay deposits and the ceramic products as well as the production steps from single clayey raw materials to their ceramic products will be analysed and experimentally reconstructed. To get more informations about the raw material treatments and the parameter of the underwent firing process, the temperature dependent behaviour of the raw material during the firing process will be analysed more closely with view to the ceramic (micro-)texture as well as the transformation and (neo-)formation of mineral phases. Qualitative and quantitative analyses include grain size analyses of the soil samples and ceramic thin sections, determination of carbon- and sulfur-content (TC, Canorg and TS) of the sediments, the bulk mineralogical compositions (PXRD, FTIR, RAMAN,TG/DTA), bulk chemical compositions (XRF, ICP-OES, ICP-MS), the chemical composition of single minerals (SEM/EDX, EPMA) in thin-sections and the statistical evaluation (PCA, discriminant function analysis, cluster analysis) of these data.