X-RAY DIFFRACTION OF EARLY IRON AGE POTTERY FROM WESTERN NORWAY

X-ray diffraction has been used to analyse the surfaces and cores of sherds from pottery from Voss and Etne. two late Roman-early Migration Period sites in western Norway. Results show: (1) the presence of illite and illite/smectite in black-burnished ware from inhumation graves which suggests that this ware was never subjected to temperatures as high as 375°C, (2) the absence of these heat-sensitive clay minerals in red ware from cremation graves at these sites which suggests a secondary firing at 700–800°C, (3) the clay minerals are similar in the cores and surfaces of the black pottery which suggests that the colour differences are due to firing procedures rather than the application of a slip, and (4) chlorite is present in all of the samples which is an indication that the ware originated in a Voss workshop where chlorite is present in other pottery found there and in the local geologic deposits.     

FIRING ANALYSIS OF SOUTH-EASTERN MISSOURI INDIAN POTTERY USING IRON MÖSSBAUER SPECTROSCOPY*

The Mössbauer spectra of prehistoric pottery and clay from the Malden Plain of south-eastern Missouri, USA, were examined. The pottery dates from AD 500 to 1400. The earlier sherds were tempered with sand and the later ones with shell. The sherds and clay contain a mixture of illite, smectite, and kaolinite. Most samples of clay and sherds contained both ferric and ferrous species. The spectral parameters for the ferric species were %DLE_Q～0. 7—1.1 mms^-1 and δ～0.0–0.3 mms^-1 for the ferrous species, ΔE_Q～2.1–2.7mms^-1 and δ～0.7–1.0mms^-1. The ferric to ferrous ratio is more accurately determined from the spectra than from consideration of the colour or the firing core of the sherds, which are not always related to the iron species ratio. Differences among sherds in the ferrous ΔE_Q can be related to original temperature of heating but with low precision.     

THE USE OF SHELL-TEMPERED POTTERY IN THE CADDO AREA OF THE SOUTHEASTERN UNITED STATES

Abstract

Freshwater mussel shell was used as a temper in the manufacture of ceramic vessels by potters in the Caddo area of the southeastern United States after ca. A.D. 1300. This was at least one or two centuries after it became the dominant temper used by aboriginal groups in much of the Eastern Woodlands but generally contemporaneous with shelltempered usage in parts of the Southern Plains. The introduction of shell temper was variable across the Caddo area, and in certain regions its use was negligible in ceramic vessel assemblages until the sixteenth and seventeenth centuries but then was rapidly adopted as the dominant temper employed in vessel manufacture, particularly for utility wares. In the traditional territory of the historic Hasinai Caddo in East Texas, shell temper did not appear in vessels until the early eighteenth century, and then only in minor amounts on presumed trade vessels.     

SCIENTIFIC INVESTIGATIONS OF THE SOPRON-KRAUT ACKER IRON AGE POTTERY WORKSHOP

Excavations at the Celtic settlement of Sopron-Krautacker (W. Hungary) make it possible to form an overall view on the local practice of pottery manufacture. Study of the soil conditions has established that the source of raw material is the nearly calcium carbonate-free upper layer of the local soil resulting from a leaching process. By the various analytical methods used (XRD, XRF spectroscopy, and thermal analysis) composition of the pottery has been determined, and it has been shown that the vessels were fired at 600–700 °C.     

MÖSSBAUER SPECTRA OF IRON IN CERAMICS AND THEIR RELATION TO POTTERY COLOURS

The chemical states of iron in a few selected clays and ceramics have been ascertained employing the technique of Mössbauer absorption. The effects upon the iron in firing the clays under different conditions have also been measured. Colour changes are correlated with the various chemical states of iron before and aftefiring.     

PIGMENT IDENTIFICATION IN GREEK POTTERY BY RAMAN MICROSPECTROSCOPY*

Raman microspectroscopy (RMS) is now established as a key technique for the identification of pigments of archaeological pottery that permits the in situ study of art objects by a non‐destructive procedure. The information obtained represents a great aid to restoration and conservation techniques. In this work, the chemical nature of the red, black and white pigments of five samples of Greek pottery from the end of the fifth century and the first half of the fourth century bc , exhumed from the Iberian necropolis of Cabezo Lucero (Guardamar del Segura, Alicante, Spain), has been identified. The black and the red pigments are found to be magnetite (Fe₃O₄) and hematite (α‐Fe₂O₃), respectively. The white pigment is found, for the first time, to be composed of alumina (α‐Al₂O₃ and γ‐Al₂O₃) probably yielded by the thermal decomposition of Greek bauxite.     

PORE-SIZE DISTRIBUTION DETERMINATIONS IN NEOLITHIC,IRON AGE,ROMAN AND OTHER POTTERY

A method of evaluating the pore-size distribution of pottery is described and results obtained from a number of samples ranging from Neolithic to modern pottery shown graphically. The method may serve to distinguish between similar-looking sherds if no other means of identification exists, but further work is needed before a series of determining curves can be established.     

THE OCCURRENCE OF DRILLED HOLES IN LATER NEOLITHIC POTTERY

Summary. Holes drilled after firing are an occasional occurrence in earlier prehistoric pottery, and are generally accepted as intended to enable repair of cracks or breaks by binding. It would seem reasonable to expect that rates of repair would be fairly consistent, but this is not the case with later Neolithic ceramics in southern Britain. There, drilled holes are more common in the Grooved Ware tradition than in the Beaker or Peterborough traditions, and it is suggested that this may be owing to the high symbolic content of Grooved Ware rendering the repair of such vessels particularly worthwhile to their users. Other factors likely to influence the decision to repair rather than discard vessels are considered, and in this connection the fabrics of repaired vessels in the earlier Neolithic assemblage at Maiden Castle are also briefly discussed. A short list of sites with repaired vessels is appended.     

THERMOLUMINESCENT DATING OF COLOMBIAN POTTERY IN THE YOTOCO STYLE

Two contexts from the Colombian sites, Yotoco Ferry and Moralba, had been linked by archaeological similarities in pottery style, and dated by association with ware from other sites at circaa.d. 1000. However, radiocarbon dating of those contexts set Moralba at circa 800 b.c. , some 2000 yr older than Yotoco Ferry. Thermoluminescent dating of pottery from Yotoco Ferry dated it at circaa.d. 900, and pottery from Moralba was dated at circaa.d. 870. In addition a metal-smelting pottery crucible, thought to be prehispanic, was studied by thermoluminescence and dated, on the contrary, at less than 120 yr old.     

COMPARATIVE STUDY OF VARIOUS SAMPLES OF ETRUSCAN BUCCHERO BY X-RAY DIFFRACTION,X-RAY SPECTROMETRY,AND THERMOANALYSIS

In order to ascertain whether the technology of Etruscan bucchero was similar everywhere or showed local variation, a comparative study was carried out on 23 samples of bucchero from different sites. The use of carbon dust as a black pigment in this type of pottery was confirmed in all samples, while the hypothesis of the addition of MnO₂ as a colouring was disproved. Further information on the nature of the basic constituents of Etruscan bucchero was also provided.     

DISCRIMINATION BETWEEN ETRUSCAN POTTERY AND RECENT IMITATIONS BY MEANS OF THERMAL ANALYSES

Black bucchero and red pottery of Etruscan production (Cerveteri, seventh-fifth century B.C.), made from the local Pliocene clay, acquire the property of quickly adsorbing and releasing water after heating up to 300°C. Thermal analysis thus allows easy discrimination between ancient artefacts and recent imitations found to be impervious to water.     

ALTERATION PROCESSES OF POTTERY IN LAGOON‐LIKE ENVIRONMENTS

Post‐depositional processes in pottery can give rise to chemical and mineralogical alterations, the extent of which is closely related not only to the microstructure and composition of the potsherds, but also to the chemical–physical conditions of the burial environment. The present paper describes the characterization of post‐depositional alterations and identification of processes involving pottery buried in lagoon‐like environments. A set of various types of Roman transport amphorae and African Red Slip ware (ARS), collected from two archaeological sites characterized by a lagoon‐like depositional environment and showing evident changes in the original colours, was analysed by a combination of microstructural, mineralogical and microchemical approaches. The formation of pyrite after hematite, jarosite after pyrite and microstructural substitution features are interpreted here in terms of the chemico‐physical conditions of the burial environment and their evolution in time.