The clay deposit of Vila Nova da Rainha (VNR) is included in the lithostratigraphic formation named "Argilas de Tomar", and is located at the lower section of the Tertiary Tagus’ river basin. Clay from one quarry is being extracted for the production of construction ceramics. In this work the firing transformations undergone by VNR clays containing quartz, alkaline feldspar, iron oxy-hydroxides, and clay minerals have been studied. Carbonates have not been identified in these raw materials. The clay layers can be subdivided in three groups based upon composition and ceramic properties. The first group, VNR0, is represented by smectite-kaolinite sandy-silty clay, the second group (VNR1 and VNR2) corresponds to illite-kaolinite bearing clay and the third group (VNR3 and VNR4) is represented by illite-smectite silty clay. The firing process involves the formation of hematite and mullite both influencing the technical properties of the fired products. With regards to the ceramic properties assessed at 1100 ºC the first group showed the lowest total shrinkage value (7.35 %) the highest water absorption value (12.2 %) and the lowest mechanical bending strength value (12.0 MPa); the same properties assessed in the second group provided the highest firing shrinkage values (7.0-5.0 %), the lowest values of water absorption (0.1-0.2 %) and relatively high mechanical bending strength values (47.8-48.0 MPa); the third group showed firing shrinkage values within the range 3.5-4.2 %, water absorption values within the range 1.4-4.5 %, and the highest mechanical bending strength values (49.2-52.0 MPa). The results of the ceramic properties being appraised indicate that the raw materials being studied are suitable for the production of high-quality construction ceramics, such as brick, roof tile and rustic floor tile., João F. Coroado, Eduardo Ferraz, Celso F. Gomes and Fernando Rocha., and Obsahuje bibliografii
This paper reconstructs the rules governing the selection of ceramic raw material and considers certain technological aspects of the production of ceramic vessels in some Danubian cultures around the Carpathians in the Neolithic. The analysis encompassed more than 500 samples of ceramics produced by various cultural units across different chronological horizons. The results of the analysis are used to verify several hypotheses concerning the relationships and the mechanisms of cultural change in the Carpathian region. The most important questions include: (1) evolution of the LBK ceramics, (2) influence of the ALPC on the evolution of the LBK pottery in Małopolska, (3) technology of the LBK ceramics east of the Carpathians, (4) culture change at the turn of the LBK and the MC in Małopolska and (5) culture change at the turn of the MC and the L-VC in the same region. The suitability of the pottery technological analysis to solve some prehistoric problems was confirmed. and Článek rekonstruuje pravidla ovládající výběr keramických surovin a zvažuje určité technologické aspekty výroby keramických nádob v některých podunajských kulturách neolitu v oblasti Karpat. Analyzováno bylo více než 500 keramických vzorků vytvořených různými kulturními jednotkami různých chronologických horizontů. Výsledky analýzy slouží k ověření několika hypotéz týkajících se souvislostí a mechanismů kulturní změny v karpatské oblasti. Mezi nejdůležitější otázky patří: (1) vývoj LBK keramiky, (2) vliv ALPC na vývoj LBK keramiky v Malopolsku, (3) technologie LBK keramiky východně od Karpat, (4) kulturní změna na přechodu mezi LBK a MC v Malopolsku, (5) kulturní změna na přechodu mezi MC a L-VC v téže oblasti. Výsledky potvrzují vhodnost analýzy technologie keramiky pro objasnění některých otázek pravěku.