How Did Mississippians Prepare Maize? The Application of Compound‐Specific Carbon Isotope Analysis to Absorbed Pottery Residues From Several Mississippi Valley Sites

A newly developed compound‐specific stable carbon isotope technique allows the detection of maize in absorbed organic pottery residues. This method was applied to absorbed organic residues from a variety of Mississippi Valley potsherds, and successfully identified maize components. Maize was cooked in sampled vessels less often than expected, but otherwise fitted expected patterns of maize use derived from stable carbon isotope analysis of human bone from the region. Absorbed organic pottery residue analysis is useful in determining pottery use, particularly in concert with other analytical methods.     

INVESTIGATION ON ROMAN LEAD GLAZE FROM CANOSA: RESULTS OF CHEMICAL ANALYSES*

Five sherds of green glazed pottery excavated at Canosa (Apulia) in Italy have been analysed by scanning electron microscopy. The aim of the investigation was to determine the chemical composition of the glazes and thus obtain information on the methods used in their production. The glazes were all of the high‐lead type, coloured green by the addition of copper. Intermediate layers, observed at the interface between the glaze and body and giving the appearance of an applied white slip, were the result of the crystallization of lead feldspar from the molten glaze. Non‐calcareous clays were used in the production of the pottery bodies. Concentration profiles from the glaze exterior to the body suggested that the glazes were produced by applying a suspension consisting of lead oxide plus silica to the bodies. On the basis of the glaze and body compositions, it is suggested that the Canosa glazed pottery was produced locally.     

GLAZED CERAMIC MANUFACTURING IN SOUTHERN TUSCANY (ITALY): EVIDENCE OF TECHNOLOGICAL CONTINUITY THROUGHOUT THE MEDIEVAL PERIOD (10TH–14TH CENTURIES)*

Archaeometric investigation allowed the characterization of two important classes of ceramics: ‘vetrina sparsa’ and ‘invetriata grezza’. Their archaeological peculiarity makes them particularly suited for tracing the evolution of glaze manufacturing in southern Tuscany throughout the medieval period (10th–14th centuries). These ceramics were found in different sites of historical importance, and also from a mining perspective. Local copper, lead, zinc and iron mineralizations supported the growth of several settlements in the vicinity of the mines. The many castles and different archaeological finds (ceramics, glazed ceramic, slag etc.) attest to the intense mineral exploitation of the area from at least the first millennium bc up to the modern period. In light of these geological and archaeological characteristics, archaeometric investigation was intended to provide insight into ancient technical knowledge of ceramic glazing and to determine the source area for raw materials in the medieval period (10th–14th centuries). Ceramic bodies were analysed through OM, XRDp, SEM–EDS and XRF, while coatings were investigated through SEM–EDS. Mineralogical, petrographic and chemical analyses revealed slightly different preparation and firing processes for the two classes of ceramics. These data suggest the continuity through the centuries of the ‘vetrina sparsa’ and ‘invetriata grezza’ production technology. The mineralogical phases, such as monazite, xenotime, zircon, barite, Ti oxide, ilmenite, titanite, tourmaline and ilvaite, and the lithic (intrusive and volcanic) fragments detected within the ceramic bodies suggest a source area in the vicinity of the Campiglia mining district. Lastly, the presence of Cu–Zn–Pb (Ag) and Fe sulphide mineralizations (materials used to produce glaze) in the area supports the hypothesis of local manufacture.     

NUCLEAR MAGNETIC RESONANCE SPECTROSCOPIC AND ISOTOPIC ANALYSIS OF CARBONIZED RESIDUES FROM SUBARCTIC CANADIAN PREHISTORIC POTTERY

Late prehistoric pottery is found in abundance at archaeological sites around Southern Indian Lake. Black residues, found on the two dominant vessel forms, flat plates and round pots, are presumed to be the remains of prehistoric meals. ¹³C cross-polarization magic-angle-spinning nuclear magnetic resonance spectroscopy (CPMAS NMR) and¹³C and¹⁵ N isotopic ratios and C/N ratios are used to reconstruct prehistoric diet and to shed light on possible uses for the plates. Samples of foods were cooked in clay pots, on a wood fire, to simulate the conditions of burning that could have produced the residue. Decomposition of carbohydrates, protein, and fat during cooking is studied with ¹³C CPMAS NMR, and the effect of cooking on isotopic and C/N ratios documented. Predominantly fish and fat were cooked in the pots, whereas the residues from plates contain a greater proportion of fat and could have been used as frying pans or possibly as fat-burning lamps placed on the ashes of a wood fire.     

OPTICAL PROPERTIES OF TIN‐OPACIFIED GLAZES*

Tin glazes contain SnO2 particles, with a diameter similar to the wavelength of visible light, which are responsible for glaze opacification. In this paper a theoretical model to explain the optical behaviour of these glazes is developed. This model is tested by measurement of the reflectance and transmittance spectra for different optical paths in Spanish Islamic and mudejar glazed ceramics and it is shown to be valid by total reflectance non‐destructive measurements on a wide range of other Islamic and related glazed ceramics.     

ACCESSORY MINERALS AS TRACERS IN THE PROVENANCING OF ARCHAEOLOGICAL MARBLES,USED IN COMBINATION WITH ISOTOPIC AND PETROGRAPHIC DATA*

Thirty‐eight archaeological marbles (Roman and medieval) from Modena and Reggio Emilia (northern Italy) were provenanced using the accessory minerals as tracers and the results were compared with those inferred for the same artefacts using isotope composition and MGS (maximum grain size of calcite grains). The number of inferred possible sources is generally lower when using the mineralogical method, which therefore seems to be suited to marble provenancing.