Post‐Depositional Elemental Alterations in Pottery: Neutron Activation Analyses of Surface and Core Samples*

From 38 sherds with ‘corroded’ surfaces, two samples per sherd were examined using Neutron Activation Analysis, one from the surface and one from the core of each sherd, in order to analyse post‐depositional alterations of minor and trace elements. The most striking effect was that a leaching of Ca could be found at the surface. Another group of elements that is severely affected are the alkali metals, with Cs and Rb showing the strongest changes. A third conspicuous group of elements are the Rare Earth Elements. Finally, the effect of such alterations on a statistical data evaluation to classify pottery according to provenance is investigated.     

LEAD ISOTOPE AND TRACE ELEMENT ANALYSIS IN THE STUDY OF OVER A HUNDRED SOUTH INDIAN METAL ICONS*

Technical investigations were made on 130 South Indian statuary images and a few miscellaneous artefacts mostly sampled from the Government Museum, Madras, India, and from the Victoria and Albert Museum and the British Museum, UK. Lead isotope investigations were attempted on 60 of these, and compositional analysis for 18 elements on 115, using inductively coupled plasma optical emission spectroscopy; thus, for 40 objects both lead isotope and trace element analysis was done. From the isotopic and elemental framework, insights are obtained into some art-historical problems of images and artefacts of the Pre-Pallava, Pallava, Chola (i.e., Vijayalaya Chola), Later Chola (i.e., Chalukya-Chola and Later Pandya), Vijayanagara (and Early Nayaka) and Later Nayaka (and Maratha) dynasties, spanning the Early Christian era to the nineteenth century, along with a few other regional styles. Inferences are also made regarding provenance of the lead and the early use of zinc and brass in the early historic period (c. fourth century BC—fourth century AD).     

A SCULPTURAL MARBLE OF PRIME QUALITY IN ANTIQUITY—THE DOLOMITIC MARBLE OF THE SIVEC MOUNTAINS IN MACEDONIA

This paper presents analytical data on a major occurrence of fine‐grained dolomitic marble in the Sivec Mountains, close to the city of Prilep in today's former Yugoslavian Republic of Macedonia. This is the first presentation of an analytical database of a large‐scale source of fine‐grained dolomitic marble, whose ancient use can be demonstrated by tool marks and archaeological evidence. Many traces of ancient mining have fallen victim to a big modern quarrying operation in this area, which for decades has produced high‐quality blocks of marble (‘Macedonian Carrara’) and exported them all over the world. A combination of different analytical methods is used to characterize the marbles and to present a database for investigating ancient artefacts made of fine‐grained dolomites. Petrographic investigations revealed the very homogeneous micro‐fabric of this marble, which is of high purity with very low silicate contamination and has a maximum grain‐size of 1 mm. In addition to analysis of the stable isotopes, trace element analyses of carbonate lattice elements (Mg, Fe, Mn and Sr) were performed. An alternative method, the analysis of the chemical composition of the inclusion fluids, was also employed. On the basis of these techniques, a multivariate discrimination analysis was performed, and a clear separation of the different dolomitic marbles (Thasos, Ephesos, Proconnesos and Karacasu) was obtained. Finds of artefacts of high artistic quality made from this dolomite prove the existence of a significant workshop in the neighbourhood of the Sivec quarries. Because of its vulnerability to weathering, this fine‐grained dolomitic marble was used preferentially for indoor applications. Sculptures of prime artistic quality made of Sivec marble have so far been found in several locations of the Republic of Macedonia.     

LA–ICP–MS,SEM–EDS AND EPMA ANALYSIS OF EASTERN NORTH AMERICAN COPPER‐BASED ARTEFACTS: IMPACT OF CORROSION AND HETEROGENEITY ON THE RELIABILITY OF THE LA–ICP–MS COMPOSITIONAL RESULTS*

This study discusses the relevance of compositions obtained using laser ablation – inductively coupled plasma – mass spectrometry (LA–ICP–MS) for the purpose of identifying the provenance of copper‐based artefacts found in Virginia at Native American sites dated from the 16th to the 18th centuries. Ten artefacts were investigated by scanning electron microscopy – energy dispersive spectrometry (SEM–EDS) to visualize the corrosion and characterize the heterogeneities in the metal and electron probe micro‐analysis (EPMA) to determine separately the compositions of the intact metal and of the corrosion product. It is shown that the corroded surfaces are highly depleted in zinc but that representative concentrations can be determined by sampling the deeper, uncorroded metal. In contrast, lead values are highly variable because of the heterogeneous distribution of this metal within the bulk copper. Despite these problems, brass is easily identifiable and American native copper and European smelted copper can be unambiguously distinguished with LA–ICP–MS on unprepared artefacts using As, Ag, Ni and Sb trace elements.     

THE ORIGIN AND GEOCHEMICAL CHARACTERIZATION OF RED OCHRES FROM THE TITO BUSTILLO AND MONTE CASTILLO CAVES (NORTHERN SPAIN)*

Ochres were the most common source materials for pigments used in Palaeolithic rock art paintings. This work analyses the petrographic and geochemical signatures of different ochre samples from outcrops inside Tito Bustillo Cave and the Monte Castillo Caves using the most common techniques (petrography, XRD, SEM–EDS and ICP–MS) in archaeological pigment characterization studies. The results obtained permit the identification and characterization of the different source ochre types and, furthermore, allow the establishment of mineralogical and geochemical proxies for the study of questions related to ochre characterization, formation processes and provenance.     

ON THE INFLUENCE OF DRYING AND FIRING OF CLAY ON THE FORMATION OF TRACE ELEMENT CONCENTRATION PROFILES WITHIN POTTERY*

On experimentally fired briquettes made of five chemically and mineralogically different clays, trace element concentration profiles from the centre to the surface of the briquettes have been measured by Neutron Activation in order to examine if drying and firing of the clays lead to a mobilization and subsequent migration of single components within a sherd. Mineralogical changes during firing have been determined by X‐ray diffraction. Generally, no such migration could be found. For two clays, arsenic was lost from the briquette during firing, forming non‐constant concentration profiles. If NaCl is present in the clay paste, sodium migrates towards the surface. Additionally, in the special case in which the presence of NaCl coincides with that of calcite, the heavier alkali elements evaporate, forming significant concentration profiles within the sherd.     

FINGERPRINTING ANCIENT EGYPTIAN QUARRIES: PRELIMINARY RESULTS USING LASER ABLATION MICROPROBE-INDUCTIVELY COUPLED PLASMA-MASS SPECTROMETRY*

Microchemical analysis of minerals present in pottery and stone artefacts may help determine their provenance. Electron microprobe major element analyses of augite suggest that minor elements (Ti0₂,MnO, Aa₂O) are important in fingerprinting basalts. This points to the potential usefulness of trace elements. Augite present in six basalt samples (representing all known/suspected Pharaonic basalt quarries in northern and middle Egypt) and basaltic temper fragments in two New Kingdom pottery sherds was analysed for 28 trace elements (Sr, Ba, Th, U, Zr, Hf, Nb, Ta, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. Sc, V, Cr, Ni, Ga) by laser ablation microprobe-inductively coupled plasma-mass spectrometry (LAM-ICP-MS, laserprobe). Cluster and discriminant analysis indicate that (1) laserprobe trace element data are more effective at fingerprinting basalts than conventional electron-microprobe data and (2) basaltic temper in the two sherds does not match any of the quarries. Microbeam techniques providing trace element data may represent the future for mineral-based provenance studies.     

CHEMICAL COMPARISON OF RARE CHINESE WHITE POTTERY FROM FOUR SITES OF THE ERLITOU STATE: RESULTS AND ARCHAEOMETRICAL IMPLICATIONS

White pottery is among the most significant finds from China's earliest state, Erlitou (c. 1900–1500 bc ). Samples were primarily discovered in small numbers from elite tombs of a few sites, leading to the hypothesis that they were made at only a few locations and then circulated regionally as prestige items. To facilitate determining provenances, we compare the ICP–MS trace elements and TIMS Sr isotopes of whiteware with two soil samples from Nanwa, a possible manufacturing site, and with shards found at three other sites: Erlitou, Huizui and Nanzhai. The Nanwa shards demonstrate special elemental and Sr isotopic features. Considering the chemical observation and archaeological background together, we propose that Nanwa was a centre for whiteware production, although the two soil samples we collected there were probably not the exact materials used. Some whiteware pieces from Erlitou, Huizui and Nanzhai fall in the chemical field defined by Nanwa samples, indicating that they were possibly made at Nanwa. Many other samples from these three sites plot outside the Nanwa field, implying they were probably not Nanwa products. This study demonstrates that while chemical sourcing is very useful, firm archaeological context must remain the cornerstone of such research.     

AUTOMATION OF SOLUBILITY PROFILES USING A FLOW CELL

The solubility profile technique is a means of characterizing the mineral phase of bones and fossils from archaeological and palaeontological sites. The method is based on the differential dissolution of variously substituted apatites in acetate buffer at pH 4.5. The original solubility profile protocol, which involves repetitive washing and centrifuging, is extremely cumbersome and time-consuming. Here we describe an alternative, automatic method in which the fossil bone preparations are dissolved in a perspex cell. The behaviour of fossil preparations in the manual and automatic protocols are compared. We conclude that the dissolution cell is satisfactory for routine applications, but that the original, manual protocol is preferable for preliminary investigation of untested assemblages.     

Geographical Variation of Subsistence Strategies in Early Mediaeval Populations of Southwestern Germany

The investigation is based on bone element data of early Mediaeval human skeletal samples from eight differing environmental conditions in lowland and mountain range localities of southern Germany. Reconstruction of plausible subsistence strategies revealed close correlations with the respective ecological potentials of the localities as indicated by proxy data on geomorphology, climate, and soil quality. In general, lowland situations showed mixed dietary patterns with a prevalence of agricultural farming, whereas in mountainous areas the emphasis was on dairy farming production and horticulture. This points to subsistence activities during the early Middle Ages that are closely adjusted to differing environmental conditions. An obvious deviation from this pattern in one locality (Kirchheim unter Teck) is explained in terms of successful socio-cultural buffering of limited but effective exploitation of the natural setting.