The Organization of Pottery Production

A brief discussion of two traditional approaches in the study of pottery production organization, ceramic ecology and typologies of production, identifies several key problems. In order to move forward and develop new strategies, it is proposed to adopt a symmetrical perspective, integrating methods and concepts from a variety of theoretical origins, including chaîne opératoire, object biography, relevant user groups or cadena, and entanglement. A brief case study outlining a proposed strategy for a relational approach to the study of ceramic production organization concludes the chapter.

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Laser Ablation Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS)

Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is a versatile technique capable of measuring nearly every element on the Periodic Table down to extremely low concentrations. Using liquid sampling, it is a powerful method for bulk compositional characterization but has been only sporadically applied to archaeological ceramic studies. With laser ablation sampling, ICP-MS can be used to produce spatially resolved chemical information and has a wide range of archaeological applications including the analysis of ceramic surface treatments, paste composition, temper composition, and identification of post-burial chemical alteration. ICP-MS and LA-ICP-MS are particularly valuable when used in conjunction with bulk and mineralogical characterization techniques to elucidate which potential cultural, geological, or environmental effects are responsible for bulk compositional patterning, as well as providing complimentary compositional provenance information for individual phases of ceramic paste.

X-Ray Powder Diffraction (XRPD)

X-ray powder diffraction (XRPD) is an important tool to determine the phase composition of archaeological ceramics. In principle, a thin beam of X-rays incident to a lattice plane of crystalline matter is scattered in specific directions and angles depending on the distances of atoms. This allows determination of characteristic unit cell dimensions and serves to unambiguously identify crystalline phases in the ceramics. In this chapter, generation of X-rays and the theory of diffraction will be briefly discussed as well as equipment, focusing conditions, and sample preparation procedures of common XRPD methods. The X-ray pattern obtained will provide an analytical fingerprint that can be matched against the Powder Diffraction File of the International Centre for Diffraction Data. Examples will be given of application of this analytical technique to archaeological clays and ceramics.

Organic Inclusions

Organic inclusions in ceramics may occur naturally in clay deposits or be intentionally added to the paste as temper. In the first case, the inclusions are composed of entire microscopic organisms and/or parts of microscopic and macroscopic plants and animals found in the local environment. In the second case, the plant or animal tempers are specifically selected, used alone or mixed with other organic or inorganic tempers, and come from a wide variety of geographic and ecological contexts. During firing, organic compounds undergo partial to complete destruction; charred organic materials or their heat-resistant remnants are nevertheless useful for the identification of their origin. The use of different tempers provides valuable information about ceramic technologies and regional potting traditions. In addition, organic inclusions may demarcate the geographical area of ceramic manufacture, the depositional environment of the clay, and/or ancient agricultural practices in the area of production.

Handheld Portable Energy-Dispersive X-Ray Fluorescence Spectrometry (pXRF)

Handheld portable energy-dispersive X-ray fluorescence (pXRF) spectrometry is used for non-destructive chemical characterization of archaeological ceramics. Portable XRF can provide adequate analytical sensitivity to discriminate geochemically distinct ceramic pastes, and to identify compositional clusters that correlate with data patterns acquired by NAA or other high sensitivity techniques. However, successful non-destructive analysis of unprepared inhomogeneous ceramic samples requires matrix-defined scientific protocols to control matrix effects which reduce the sensitivity and precision of the instrumentation. Quantification of the measured fluorescence intensities into absolute concentration values and detection of light elements is encumbered by the lack of matrix matched calibration and proper vacuum facilities. Nevertheless, semi-quantitative values for a limited range of high Z elements can be generated. Unstandardized results are difficult to validate by others, and decreased analytical resolution of non-destructive surface analysis may disadvantage site-specific sourcing, jeopardize correct group assignments, and lead to under-interpretation of ceramic craft and production systems.

Fabric Description of Archaeological Ceramics

Fabric description is fundamental to the characterization, technological analysis and provenance determination of archaeological ceramics. It encompasses description of the arrangement, size, shape, frequency and composition of ceramic material constituents. These properties are used to identify the raw materials, their processing, vessel construction methods, and firing conditions. The process of description should, so far as possible, be an objective record of observed fabric properties that is independent of interpretations concerning technology and provenance. Fabric descriptions are made of ceramics in hand specimen and of samples prepared as thin sections for examination under a polarizing microscope. Rapid evaluation of fabric properties in the field is achieved by studying hand specimens using a magnifying glass or stereomicroscope. Laboratory-based analysis of thin sections provides more accurate and comprehensive identification of fabric properties, especially mineral and rock fragments in coarse fabrics, in terms of qualitative and quantitative data.

Particle Induced X-ray Emission (PIXE) and Its Applications for Ceramic Analysis

Systematic research into art and cultural heritage objects in museum collections are growing daily across the world. They are generally undertaken in partnership with archaeologists, curators, historians, conservators, and restorers. The use of scientific methods to answer specific questions about objects produced by different societies reveals the materials and technologies used in the past and gives us a better understanding of the history of migration processes, cultural characteristics, and thereby more grounded parameters for the preservation and conservation of cultural heritage. The use of non-destructive methods, such as the PIXE analysis, is very suitable in such studies because damage or alteration is avoided and the integrity of the object maintained. Such techniques gave historians and curators at the Archaeological and Ethnology Museum in São Paulo new understanding of the Chimu collection of ceramics as well as of the technical process of preventive conservation.

Petrography

Petrography has developed into an indispensable tool for ceramic fabric analysis, specifically studying the mineralogical and textural composition of ceramic objects. Petrography is a technique commonly used in geology to describe and classify rocks. Ceramic petrography studies clay-based archaeological or historical materials. Using a polarizing light microscope (PLM) in ceramic studies, the different raw materials used to make a ceramic object can be identified, ranging from clays and other minerals to rock fragments and inorganic or organic temper. The technique moreover feeds into the study of raw material provenance and origin, and is able to discern the different technological procedures followed to make the ceramic object (from shaping to firing), next to providing clues on the function of the object. This information not only helps reconstruct trade and exchange of raw materials and ceramics, but aids in reconstructing society behind the pot.

Ceramic Micropalaeontology

Microfossils found in archaeological ceramics include representatives of kingdoms Fungi, Protista, Plantae, and Animalia and are composed of calcite, silica, or resistant organic compounds capable of withstanding firing. Methods by which microfossils are isolated for study vary considerably, but the best results involve the disaggregation of potsherds into their individual grains or by cutting petrological thin sections. Microfossils can be related directly to the age and depositional environment of the source materials (clays, temper, and slip) used in the manufacturing process, although the introduction of contaminants at the time of construction must also be recognized. When incorporated into an integrated analysis, the microfossils may demonstrate provenance; contribute to a better understanding of the local environment and landscape; identify transportation routes; contribute to an understanding of the technology used, including construction methods and firing; and elucidate the use to which the vessels were put.

Isotope Analysis

Lithogenic isotopes of strontium (Sr), neodymium (Nd), and lead (Pb) are a powerful tool for the study of the composition and origin of pre-historic ceramics and their raw materials. Despite their use in classical geochronology and isotope-geochemical provenance studies of rocks and minerals, Sr, Nd, and Pb isotope ratios have so far scarcely been used in archaeological provenance studies of ceramics and glazes. The following chapter provides an overview of the basics for application of lithogenic isotopes to ceramic provenance research specifically focusing on chemical preparation of samples, mass spectrometric analysis techniques, and interpretation of analytical results. Examples of currently available research results are discussed with respect to the respective isotope systems.