Late Roman cooking pottery from the Tavoliere area (Southern Italy): raw materials and technological aspects

Abstract

This study describes the results of petrographical, mineralogical and chemical analyses carried out on coarse tempered cooking pottery, sampled in the archaeological sites of Herdonia, Posta Crusta (Ordona, FG) and San Giusto (Lucera, FG). From the latter site, two fragments of a pottery kiln, coeval with sherds (IV and V centuries AD), were also investigated. Two groups of clayey sediments of different nature (alluvial and marine) sampled in the neighbouring of the archaeological sites were also analysed. By means of the petrographical analyses, all cooking pottery and the two kiln fragments were grouped in the same coarse tempered group, characterised by the scarce presence of trachytic and glassy fragments, anhedral and zoned augitic pyroxenes and feldspars. PXRD analyses show an abundant presence of quartz and feldspars, followed by pyroxenes and variable quantities of calcite and hematite. Among clay minerals, illite plus muscovite are more abundant than smectite. XRF analyses data display SiO 2 , Al 2 O 3 , Fe 2 O 3 and K 2 O as main oxides, with variable quantities of CaO. In the case of the clayey samples, petrographical investigations on thin-section of psammitic fractions outlined the differences between Argille subappennine (Marine group-Pleistocene) and the alluvial deposits of Celone River (Alluvial group-Holocene). The occurrence of volcanic products, chert, garnet, quartzarenites and limestones in the archaeological materials and in the alluvial samples, let us suppose that cooking pottery was made with alluvial clayey silt. The apparent chemical discordance between pottery and alluvial samples bulk compositions can be due to textural and compositional variability of the alluvial deposits. All ceramics were fired in oxidising conditions, although in many cases a "dark core" was still present. Textural features, observed through petrographical microscope, and PXRD analyses suggested a firing temperature between 600 and 800°C.

Strength of kaolinite-based ceramics: Comparison between limestone- and quartz-tempered bodies

“…Such types of temper were added to three different clays, (1) kaolinitic clay poor in iron, (2) kaolinitic clay rich in iron and (3) illitic calcareous clay, taking into account their firing characteristics as reported in several publications (e.g. Maggetti and Rosmanith, 1981;Maggetti, 1982;Riccardi et al, 1999;Cultrone et al, 2001;Eramo et al, 2004). In this paper, we report the results obtained from ceramic tests prepared with a clay of the first type, which could be assimilated to earthenwares produced by primary clays (e.g.…”

“…The two most common mineral phases present in temper are quartz and calcite (Rice, 1987;Rye, 2002;Broekmans et al, 2004;Eramo et al, 2004;Orton et al, 2008). According to the firing temperature used, these two materials face different mineralogical changes which affect the microstructure on the fired product and its physical properties .…”

From the kilns to the fair: producing building materials at Faragola and Canusium (northern Apulia, Italy)

“…The mineralogical and petrographical assemblages described so far in north Apulian productions were various but lacking of strong discriminant features as expected based on regional geology (Eramo et al 2004(Eramo et al , 2014Gliozzo et al 2005Gliozzo et al , 2010Gliozzo et al , 2013Gliozzo et al , 2014. The presence or the absence of clinopyroxene and volcanites allowed the creation of the groups 1-3.…”

“…From an archaeometric point of view, a few ceramic productions of northern Apulia have been systematically investigated, although including table ware or cooking ware or storage ware (Cioni et al 2000;De Benedetto et al 2004;Eramo et al 2004Eramo et al , 2014Gliozzo et al 2005Gliozzo et al , 2010Gliozzo et al , 2014Mangone et al 2008; Thorn and Glascock 2010).…”

Investigation by pXRF of Caltagirone Pottery Samples Produced in Laboratory

“…In some studies considering the effect of changes in firing temperature on microstructure and physical properties of clay, XRF has been used for bulk chemical analyses (Cultrone, Rodriguez-Navarro, Sebastian, Cazalla, & De La Torre, 2001;Eramo, Laviano, Muntoni, & Volpe, 2004;Kurama, Kara, & Kurama, 2006;Johari, Said, Hisham, Bakar & Ahmad, 2010).…”