The influence of different tempers on the composition of pottery

The modification of the raw clay by the potter to produce a paste suitable for the intended purposes adds a layer of obfuscation to the problem of provenancing the original clay source by chemical fingerprinting. By preparing different pastes from the same commercially available raw clay and their chemical analysis by Instrumental Neutron Activation Analysis, an experiment under controlled conditions (tempers, mixing ratios, firing temperatures and sampling methods) sheds light on the influence of different tempers.     

Using provenance data to assess archaeological landscapes: an example from Calabria, Italy

Ceramic provenance studies have helped archaeologists examine trade and exchange in multiple scales, the organization of production, and even vessel function. Yet, they may go even further, to provide a venue for the examination of past people’s perception of their landscape. To do so, a methodology is needed that links the choices prehistoric potters made, as reflected in their ceramics, with the choices their landscape could afford them, as reflected in the extent and distribution of local clays, and the physical, chemical and mineralogical characteristics of these clays. Using the region of Bova Marina in southwestern Calabria as a case study, we have combined a raw materials survey with field and laboratory experiments, along with chemical and mineralogical analyses of the collected sediments to understand the distribution and the physical, chemical and mineralogical variability of locally available clays and provide baseline data against which prehistoric ceramic materials from the region may be compared. We show that the local sediments can be divided into three major units, based on their macroscopic, mineralogical and chemical characteristics, that correspond well with the major geological units outcropping in the study area. While two of these units have internally consistent properties, the third is variable.     

EFFECTS OF MILLING: A POSSIBLE FACTOR INFLUENCING THE DURABILITY OF HISTORICAL MORTARS

In their literary texts, some classical Roman authors such as Gaius Plinius Secundus and Marcus Vitruvius Pollio stress the importance of milling when preparing mortars. Following these indications, this work describes the effects of milling between lime (calcium hydroxide) and clay brick powder before and after the addition of water. Starting and resulting materials were investigated by XRPD, SEM/EDS, differential scanning calorimetry and thermogravimetry (DSC/TC), colorimetry, densimetry and porosimetry. Prolonged milling changes the mineralogy of the starting materials and increases their reactivity. The final lime pastes, starting from materials milled for varying periods of time, had different mineralogical and physical characteristics. These results may help to clarify the reasons for the marked differences in durability of some historical mortars.     

The geochemical diversity of neogene clay deposits in Crete and its implications for provenance studies of Minoan pottery*

The determination of provenance probably forms the primary role of geochemical analyses in archaeological ceramic studies. In what has comprised a successful field of study, the ultimate basis for such research has been the comparison of pottery compositions with the geochemical diversity displayed by clay deposits within a given study area. Although such studies are now common, the understanding of chemical and mineralogical variability in ceramic raw materials has been somewhat neglected, with the dominance of assumptions rather than the actual analysis of clays. In this paper, a study is presented of Neogene clays in Crete (Greece), a clay type commonly used in ancient and modern pottery production. Sixty‐one samples were taken from 28 locations in the central and eastern parts of the island, to reveal both intra‐ and inter‐deposit variability. In one deposit chosen for multiple sampling, the 14 samples display great variability in the alkali elements, Fe and Co, and to a lesser extent in the REEs. Many of the geographically separate deposits differ from each other in chemical composition, with Eastern Cretan deposits showing higher REE concentrations and higher Th/Sc ratios, whereas Central Cretan deposits of younger geological stages are characterized by a lower Th/U ratio. Mineralogical analysis by XRD is used to explain aspects of the geochemical variability of the clays.     

江苏武进淹城龙墩墓葬发掘简报

武进淹城龙墩发掘,清理古代墓葬6座,出土陶器、原始青瓷器近百件,时代约在西周中晚期至春秋早期之间。     

Selinunte (Sicily) and its productive context: the clayey raw materials applied in a long-lived ceramic production (seventh to third century BCE)

The westernmost of the Greek-Sicilian towns, Selinunte, founded in western Sicily during the second half of the seventh century BCE, gives amazing evidences of a historic activity of ceramic production (seventh to third century BCE). The present study aims to identify the raw materials available in the vicinity of the archaeological site of Selinunte, which were possibly used by the ancient potters, and to characterise them by means of petrographic and chemical techniques. A sampling campaign of clays and sands for tempering was undertaken in the archaeological site and the adjacent area. Moreover, locally produced archaeological bricks and tiles were considered helpful for comparison regarding the definition of local ceramic macro- and micro-fabrics and were analysed as well. The comparison between textural, mineralogical and chemical data allowed us to highlight a good similarity between the clayey materials available in the area and the local ancient bricks and tiles. Their compositional resemblance suggests the hypothesis of a systematic use of the studied clays for ceramic productions from the Archaic to the Hellenistic period. The preliminary archaeometric results obtained so far could enhance the distinction between local manufactures and imports and may well lead to the identification of ceramic artefacts produced by the Archaic-Hellenistic workshops of Selinunte at various consumption sites.     

Ceramic Technology and Social Boundaries: Cultural Practices in Kalinga Clay Selection and Use

This study examines cultural sources of variation in ceramic compositional patterning in two pottery-making villages of the highland Philippines. In Dalupa, many potters are part-time specialists whereas in Dangtalan, women make pottery less frequently. Previous studies show that both pottery form and decoration correspond well with Kalinga social boundaries, but how do morphological and decorative patterning relate to compositional variability? Although researchers have made substantial advances in our understanding of natural and postdepositional sources of compositional variability, little is known about behavioral factors that affect chemical and mineralogical compositional patterning. This study examines cultural practices of clay selection and use in an ethnographic setting, and undertakes technical analyses to assess the relationship between behavior and material culture patterning. Our study identified paste differences between the clays and fired ceramics from Dangtalan and those from Dalupa. Findings from our compositional research thus parallel earlier morphological and stylistic studies, and illustrate multivariate differences in ceramics from these two Kalinga communities. This ethnoarchaeological and analytical project contributes, therefore, to understanding objective parameters within a behavioral context. It also provides an example of how a combined characterization approach, using chemical and petrographic techniques, can yield insights on intraregional variation at a finer scale of resolution than is often attempted.     

PETROGRAPHIC AND GEOCHEMICAL EVIDENCE FOR LONG‐STANDING SUPPLY OF RAW MATERIALS IN NEOLITHIC POTTERY (MENDANDIA SITE,SPAIN)

Pottery from the Neolithic Mendandia site has been studied. The radiocarbon dating of the site corresponds to a range of dates from 7488–7546 cal bc to 5283–5437 cal bc : the first occurrence of pottery is dated at 5968–6040 cal bc for the lower level III, and up to 5386–5560 cal bc for level II. The antiquity of the potsherds places them within the oldest pottery production sequences in the Iberian Peninsula, which adds to the interest of this study. Ten potsherds from level II and five from level III are analysed for their petrographic and chemical characterization. The petrographic data show two different methods of raw materials manufacture—intentionally tempered pottery (ITP), using calcite and/or limestone and grog, and naturally or non‐intentionally tempered pottery (NTP). According to the matrix paste features, on the basis of the amount, shape, and average or size range of the mineral inclusions, clayed (type A) and sandy (type B) paste types were established and related to two different source areas. The chemical features also indicate two raw material sources and are in agreement with the petrographic paste types. The absence of significant chemical and mineralogical differences between the pottery from levels II and III suggests two contrasting areas for raw materials supply that lasted for at least 600 years.     

CHEMICAL ASSAYS OF TEMPER AND CLAY: MODELLING POTTERY PRODUCTION AND EXCHANGE IN THE UPLANDS NORTH OF THE PHOENIX BASIN,ARIZONA, USA*

A lack of mineralogical variation characterizes the prehistoric pottery in the uplands of central Arizona. Virtually all of the ceramics in that region were tempered with phyllite, which has previously precluded provenance analyses and the investigation of pottery production and distribution in the upland zone. As shown with assays with an electron microprobe, however, both the clay fraction and the temper fragments are chemically diverse and geographically distinct, allowing many of the phyllite‐tempered wares to be sourced, thereby leading to models about the organization of ceramic production and exchange in the upland zone north of the Phoenix Basin.     

Tracing the clay source of Nasca polychrome pottery: results from a preliminary raw material survey

This paper describes the results of the first season of a survey in which clays suitable for the production of Nasca polychrome pottery were collected in an effort to (1) determine the geological variability of clay sources in the Nasca region and (2) match clays compositionally to paste groups from previous provenance analyses. Clays were collected, processed, fired, and analyzed using neutron activation. The results demonstrate that clays in the region were compositionally heterogeneous, and that the clay source for the majority of Nasca polychrome pottery sampled thus far can be traced to lower valleys in the region near the ancient ceremonial center Cahuachi. The results have implications for understanding the nature of polychrome pottery production in the Nasca region, and suggest centralized production near the ceremonial center of the majority of painted ceramics consumed in the Southern Nasca Region.     

Long-term clay raw material selection and use in the region of Classical/Hellenistic to Early Byzantine Sagalassos (SW Turkey)

A provenance study was carried out on coarse ceramics from the Classical/Hellenistic to Mid-Byzantine city of Sagalassos, SW Turkey. The ceramics were sampled from the excavations of the city, and clay raw materials were sampled throughout its ancient territory. Used techniques were optical microscopy and electron microprobe analysis on thin sections, geochemical analysis (fusion ICP/MS and mineralogical analysis (X-ray diffraction). The geochemical/mineralogical diversity in the ceramics is not as wide as for the clay raw materials. It seems that even at the restricted scale of this study, the resources were limited to the area around the ancient site. The differences between the ceramics are likely due to the use of different ophiolitic clay bodies being exploited for their production.     

Pottery production on Rishiri Island,Japan: perspectives from X‐ray fluorescence studies

Energy‐dispersive X‐ray fluorescence (EDXRF) was used to determine the minor and trace element composition of 54 sherds of pottery dating from the Final Jomon to Okhotsk periods. The majority of the sherds came from Rishiri Island, Japan. Principal component (PC) scores were calculated using the log transformed concentration values, and groups were sought in the PC scores using kernel density estimates (KDEs). Two main groups were found in the data; linear and quadratic discriminant analysis classified both groups successfully. Significant differences in the concentrations of Cu, Fe, K, Nb, Pb, Rb, Th and Zr were found to exist between the two groups. The lack of correspondence between chronological ware types and geochemical groups implies that the same raw materials and paste recipes were in use during the Epi‐Jomon and Okhotsk eras on Rishiri Island. One possiblity is that the Epi‐Jomon and Okhotsk potters used the same clays and tempers, since no other alternatives were available. Alternatively, the Okhotsk potters could have adopted the same paste recipes as the Epi‐Jomon potters, or the Okhotsk pottery tradition could be descended from the Epi‐Jomon pottery tradition.     

HISPANO-MORESQUE POTTERY PRODUCTION OF THE FOURTEENTH-CENTURY WORKSHOP OF TESTAR DEL MOLÍ (PATERNA,SPAIN)

Excavation of Testar del Molí, the only workshop found in the Manises-Paterna area, revealed the existence of a fourteenth-century ceramic workshop covering the remains of the thirteenth-century workshop. This study is concerned with the fourteenth-century production, and forthcoming papers will connect both epochs following the findings of current excavations. The chemical and mineralogical characterization of the ceramic production of this workshop shows the presence of three groups of ceramic pastes which could also be distinguished by, and, thus, related to, their daily use. The raw materials found in the excavation have also been mineralogically and chemically characterized, and a model of possible mixtures of raw materials has also been developed in order to determine their possible use in the manufacture of the pottery previously characterized.     

A Clay source provenance survey in Northwest Alaska: Late Holocene ceramic production in the Arctic

Ceramic compositional analysis can contribute to the study of late Holocene Arctic hunter-gatherer social interaction through reconstruction of past ceramic distribution patterns. The results of an ethnographically informed clay source survey in Northwest Alaska are presented here. The survey provided contextual data on clay depositional environments, clay variability, and local environmental factors that influenced pre-contact clay availability. Geochemical analysis of clays and tempers clarified the location of ceramic production zones. Concurrence between survey results and ethnographic data highlights the persistence of clay knowledge despite post-contact absence of pottery making. This research demonstrates that ethnographically informed source survey can aid in interpreting ceramic geochemical data and yield important insights into pre-contact ceramic production processes.     

Characterization of ancient building lime mortars of Anhui province,China: A multi-analytical approach

The characterization of lime mortars has become of primary importance in order to obtain information about the raw ingredients and building technology of ancient masonry structures. Five different samples from Anhui province, China, representing two types of lime mortar-based materials: joint mortars between the bricks of the city wall and lime mortar sealing a tomb coffin, were collected for analysis. Archaeological information about the samples was reported and studies into the microtextural features and mineralogical compositions of those mortars were performed via a multi-analytical approach. The joint lime mortars between the bricks of city walls, including Mingzhongdu city wall, Mingzhongdu Xihua gate foundation, Zhengyangguan city wall and She county city wall, were found to be aerial lime mortars. The lime mortar from Nanling Tieguai Song dynasty tomb was analysed and found to be a pozzolanic mortar consisting of lime, clay, sand and cocciopesto-like materials. The analytical results serve as a critical reference for the maintenance and restoration of ancient city walls in Anhui province, and as a starting point for searching for ancient Chinese pozzolanic mortars and technology for making those mortars.     

Identifying pottery clay from rice fields: an example from southern Luzon,the Philippines

The general type of clay used by potters can often be identified from attributes of the finished ceramic vessel or sherd. This information is important for compositional and sourcing studies and may also shed light on the variables influencing clay choice such as social, economic, and landscape use patterns. Rice paddies are one type of clay source that are readily identifiable in archaeological ceramics. This paper describes rice paddy clays gathered during ethnoarchaeological studies of traditional potters in Paradijon, southern Luzon, the Philippines. We analyze the effects of clay processing and vessel manufacture on these clays and find that the most diagnostic attribute of paddy soils, the iron oxide mottling, is retained in finished vessels.     

THE EFFECT OF PURIFICATION AND FIRING OF CLAYS ON TRACE ELEMENT PROVENANCE STUDIES

The effect of purifying, mixing and firing of clays on trace element concentration was systematically investigated using instrumental neutron activation analysis. Eight different clays from two sites in Crete were used together with sherds found around several kilns near the sites. Trace element analysis showed that the extent to which the concentration changes after purification and firing depends on the initial particle size and chemistry of the clay. The calcite concentration plays an essential role in this. An application is made using roof tiles found at the excavation of the ancient city of Pella in Macedonia.     

IBERIAN CERAMIC PRODUCTION FROM BASTI (BAZA,SPAIN): FIRST GEOCHEMICAL,MINERALOGICAL AND TEXTURAL CHARACTERIZATION

Ceramic fragments from the archaeological excavation of the Iberian–Roman city of Basti (Spain) were studied from a geochemical point of view and by applying a statistical tool to X‐ray fluorescence data to discover similarities between ceramic materials. The analysis of these samples was completed by performing a mineralogical analysis, textural observation, and by characterizing the porous system and the colour of the pieces. Our results enabled us to identify the source area of the clayey raw material in the surroundings of Basti and to estimate the firing temperature of the ceramics. Differences in the chemistry were confirmed by characteristics of the pastes and the mineralogical composition of the pieces. Some samples show black cores, which would suggest the presence of organic matter in the raw material and fast firing of the ceramics. The main types of temper were quartz grains and gneiss fragments, although carbonate grains were also identified. Our evidence suggests that most of the samples were well fired. New silicate phases were found to be present in several samples. The mercury intrusion porosimetry verified and confirmed the firing temperature of non‐carbonated samples. Colorimetry showed that the colour of the ceramics varied according to the amount of CaO that they contained.     

RELATIONSHIP BETWEEN THE COLORATION AND THE FIRING TECHNOLOGY USED TO PRODUCE SUSA GLAZED CERAMICS OF THE END OF THE NEOLITHIC PERIOD*

Ancient decorated potteries from Susa (Mesopotamia) dating from 4200 to 3700 bc , were studied in order to determine the origin and the nature of the raw materials used, and to identify the technological processes applied to make the ceramic bodies and their decorations. Bulk compositions were determined by particle induced X‐ray emission (PIXE), while the microstructure and the mineralogical phases were studied using scanning electron microscopy (SEM), energy dispersive X‐ray analyses (EDX) and X‐ray powder diffraction (XRD). The results showed that the raw materials used to elaborate these potteries were similar for all the ceramic bodies (carbonates and iron and magnesium‐rich clays containing sand), and for all the decorations (iron oxides, silica, potassic and alumina sources). The variations of coloration of the ceramics and of their decorations were due to different firing temperatures. The ranges of firing temperatures used by potters were evaluated on the basis of mineral stability domains.     

CHARACTERIZATION OF LATE CHALCOLITHIC MICRO‐BEADS FROM ÇAMLIBEL TARLASI,NORTH‐CENTRAL ANATOLIA

Micro‐bead manufacture is geographically widespread from the fifth millennium bc . Previous studies of comparable micro‐beads from sites in the Indus Valley region and the Near East suggest that many of these beads were formed from synthetic enstatite. Characterization of micro‐beads from the Late Chalcolithic site of Çaml?bel Tarlas? was carried out by optical microscopy (OM), scanning electron microscopy (SEM) and microanalysis with energy‐dispersive X‐ray spectroscopy (EDS), and X‐ray diffraction analysis (XRD). The chemical composition of the micro‐beads analysed indicated that they were made from three distinctive materials; namely, bulk talc (i.e., synthetic enstatite precursor), apatite and mineral‐rich clay pastes.