This study focuses on the analysis of Islamic ceramics from the Alcaçova of Santarém, Portugal. To establish the ceramic raw material provenance and ceramic technology, a set of raw materials was sampled and compared with the archaeological ceramics. Raw materials were dry sieved to increase the clay content, to reconstruct the ceramist homogenization process, and to evaluate chemical and mineralogical variation. Results showed that two raw materials were selected for local ceramic production, whereas some artefacts were imported.
This paper focuses on the study of different Roman mortars (renders, finishing coats), used in the construction and restoration of the Forum Traiani thermal baths (Central Sardinia, Italy), a significant example of the Roman-style architecture in Sardinia. The archaeological site is located in a high hydrogeological risk area, due to the cyclical flooding of nearby Tirso river. Moreover, the presence of thermal saline (NaCl-bearing) water spring directly in contact with mortars and building stones, also contributed to structure degradation. An analytical approach, comprising mineralogical-petrographic characterization, physical analysis and particle-size distribution of aggregate, was used for mortars characterization. In addition, pXRD analysis on mortars defined the presence of alteration minerals while the thermal characterization (TGA) gave information about binder hydraulicity degree. Further μ-XRD-associated μ-Raman spectroscopy and μ-FTIR were utilized for pigments identification on frescos. Interesting results came from two wall stratigraphic series of mortars, highlighting construction stages, ancient restoring interventions and waterproofing methods. The main pigments used on red, yellow and black frescoes were red ochre, goethite and wood charcoal respectively.
This article describes the screening, ranking and characterization of ultramafic and mafic rocks in southern Portugal for mineral carbonation as an alternative to conventional CO2 storage in sedimentary rocks. A set of criteria including mineralogy, structure, surface area, distance to CO2 sources, expected volume, and socioeconomic conditions was applied to screen ultramafic and mafic rock massifs in the Alentejo region, southern Portugal. Ranking of the massifs indicated that the plutonic massifs of Sines and of Torrão‒Odivelas were the most promising. A characterization was made of the Sines massif, a subvolcanic massif composed mostly of gabbros and diorites, located immediately adjacent to the CO2 sources and outcropping along 300 km2 onshore and offshore. These studies confirmed that these rock samples exhibited the appropriate mineralogical and geochemical features, but also indicated that the secondary porosity provided by the fracture patterns was very small.
Combining historical, archaeological and experimental data, traditional and archaeological ceramics, from the Santarém district, with different chronology and functions have been studied. Our aim is to understand ancient pottery technology and to evaluate whether ceramic production followed similar principles in the Middle Ages (from the Islamic to the Christian domination) and Modern times. Moreover, traditional ceramics, knowing the productive process, have been used as a tool to interpret ancient pottery technology. We considered different utilitarian ceramic groups, namely fire, table and food-liquid container wares. Through the combination of optical microscopy (OM), X-ray powder diffraction (XRPD), X-ray fluorescence spectroscopy (XRF) with physical and mechanical tests, it has been possible to collect valuable information regarding pottery manufacturing, considering the age and the object function. Moreover, it is also considered the effect of raw materials mixing and ceramic paste preparation on ceramics final characteristics. Our results indicate that both during the Middle Ages and in Modern times, technical expertise played, and still play, a fundamental role in the creation of a specific object. In this specific case, behavioural and socio-cultural factor drove ceramists' decision when selecting between different technological solutions, and every decision or technical choice is/was taken depending on the functional and performance characteristics desired for a specific artefact. This happened during the Middle Ages, and is still happening nowadays for the production of traditional ceramics in the district of Santarém, Portugal.
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