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Caracteristici mineralogice si petrografice ale ceramicii romane din Napoca

Domenii publicaţii > Ştiinţele pământului şi planetare + Tipuri publicaţii > Capitol de carte

Autori: Ionescu, C., Ghergari, L.

Editorial: Edit. Mega Cluj-Napoca, ISBN 978-973-1868-08-0, In: Rusu-Bolindet, V. (2007) Ceramica romana din Napoca. Editura Mega Cluj-Napoca (685 p.), Biblioteca Mvsei Napocensis, XXV, p.434-462, 2007.



Samples of fine, semifine and coarse Roman ceramics were studied by means of optical microscopy in plan-polarized light and X-Ray diffraction. Based on the mineralogical and petrographic features, three main groups of ceramic body (paste) were found:
1. Fine ceramic paste (fine ceramics), with components smaller than 0.01 mm. They consist of clay minerals, quartz, micas, feldspars, carbonates and Fe-oxides. The fabric is homogeneous, with a lutitic to siltic structure and oriented to massive texture. Characteristic for the fine ceramics are the bioclasts (foraminifera), originated from the clayisch raw material. The ceramics was fired at different temperatures and two main thermal domains were inferred: between 850 and 950oC, and between 950 and 1050oC respectively. The oxidizing atmosphere was constant.
2. The semifine ceramic paste (semifine ceramics) has the most of the components smaller than 0.05 – 0.06 mm and less than 15% of all particles are larger than 0.05 mm. The semifine ceramic paste consists of clay minerals, quartz, feldspars, micas, feldspars, carbonates and Fe-oxides, similar to the fine ceramics but the amount of quartz is much higher. Thge semifine paste contains as well as fossil foraminifera. The fabric is in general oriented, with the arrangement of particles in straight or slightly curved paralel rows. The firing temperatures for the semifine ceramic paste plot in a more narrow interval, ranging from 900 and 1000oC. The firing atmosphere was an oxidizind and constant one.
3. The coarse ceramic paste (coarse ceramics) consists of clay minerals and micas, and significant amounts of quartz, feldspars, carbonates, and mainly metamorphic quartzites clasts. More than 15% of the ceramic body consist of clasts larger than 0.05 mm and fragments larger than 1-2 mm are common. Characteristic for the coarse ceramic are the potshards and hematitic soil aggregates. Carbonates and Fe-oxides are also present, the bioclasts are found occasionally. The coarse ceramics was fired at lower temperatures, between 900 and 950oC. The reducing atmosphere was not constant and zoned structure of the ceramic wall is common.
For the fine ceramics a local source was used, i.e. a Badenian calcareous, slightly siltic clay, croping out north of Napoca, on the the Somes river slopes. For the semifine and coarse ceramics similar, but coarser, light arenitic clays were used. Additionally, the potter used quartzitic sands of the Somes river alluvial sediments as tempering material.

Cuvinte cheie: Arheometrie, Ceramica romana, Napoca, compozitie, fabric, modificari termice, ardere // Archaeometry, Roman ceramics, Napoca, composition, fabric, thermal changes, firing