AN ARCHAEOMAGNETIC STUDY OF POTTERY KILNS FROM BRÜHL-PINGSDORF (GERMANY)*

Four pottery kilns from Brühl-Pingsdorf (Germany) were dated by comparing their characteristic remanent magnetization with a curve of the palaeo-secular variation of the geomagnetic field. Archaeomagnetic results suggest last heating events between AD 775 and 1020. The archaeological evidence generally supports the relative temporal succession and the duration of use, but indicates that the kilns are about 150 years younger on average. Hence, a systematic offset between these independently developed chronologies must be considered. Rock magnetic parameters display radial variations through the kiln walls. These variations are controlled by the maximum temperature the rock was exposed to. These parameters were used to identify specimen which acquired a thermoremanent magnetization.     

METHODOLOGICAL DEVELOPMENTS IN THE LUMINESCENCE DATING OF BRICK FROM ENGLISH LATE‐MEDIEVAL AND POST‐MEDIEVAL BUILDINGS*

Fired clay brick samples, obtained from a group of seven high‐status late‐medieval and post‐medieval buildings in England ranging in age from c. ad 1390 to 1740, were dated by the luminescence method using an optically stimulated luminescence (OSL) technique. The results obtained indicate that, when applied to quartz extracted from brick, the technique is capable of producing dates that are in consistently good agreement with independent dating evidence for the buildings. For six samples taken from a group of four dating ‘control’ buildings the mean difference between the central values of luminescence and assigned ages was 5 ± 10 years (SD, n = 6). The methodology used is appropriate for application to other standing buildings in other temporal and geographic regions, and may be used with confidence where conventional dating methods are less certain. The study also examines the luminescence characteristics of quartz and the characteristics of the lithogenic radionuclides in brick samples and identifies various aspects related to the assessment of experimental uncertainty in testing the reliability of the method.     

MAGNETIZATION DATING AT A MEDIEVAL MONASTERY (TUPHOLME,LINCOLNSHIRE)*

Tupholme Abbey, founded by c. 1166, was constructed of limestone masonry, some of which was reoriented at several times through its history. The limestone progressively acquired a ‘soft’, time-dependent magnetization in the earth's magnetic field—viscous remanent mag-netization (VRM)—that acts like a clock. Although VRM is normally disregarded by geologists because of its ephemeral nature, this remanence is acquired and persists over time-scales that are useful to archaeologists. Successive VRMs were initiated, at different ages of stabilization of the masonry, thus yielding a chronometric curve that allows us to determine, at least relatively, when masonry was installed.     

ARCHAEOMAGNETIC FIELD INTENSITY DURING THE ROMAN PERIOD AT SIWA AND BAHRYN OASIS,EGYPT: IMPLICATIONS FOR THE FIDELITY OF EGYPTIAN ARCHAEOMAGNETIC DATA

A preliminary survey was conducted in Siwa and Bahryn Oasis to test the possible influence of various rock magnetic and experimental constraints on the fidelity of the Egyptian archaeomagnetic field record. Five potsherds from the Roman era, which lasted from 1981 bp to 1555 bp , have been investigated. Archaeologists dated the localities to ～1620 bp . Ten ceramic specimens, two of each potsherd, were subjected to archaeointensity determination, including tests for domain state effects, magnetic anisotropy and magnetic cooling rate dependency. Six successful archaeointensity determinations are obtained from three individual cooling units, revealing an average field value of 37.7 μT for the late Roman period in Siwa and Bahryn oasis, which is comparable to the present‐day field strength. The error propagation of the individual uncertainties related to all applied experimental techniques results in a maximum uncertainty estimate of 4.4 μT. The obtained field value is significantly smaller than early results and slightly smaller than some more recent determinations of the field intensity in Egypt. The difference is attributed to a combined effect of alteration, magnetic anisotropy and magnetic cooling rate dependencies. Along with other high‐quality data from the south‐east Mediterranean, our data suggest a field intensity minimum during the Egyptian Roman era.     

POST‐MEDIEVAL CRUCIBLE PRODUCTION AND DISTRIBUTION: A STUDY OF MATERIALS AND MATERIALITIES*

This paper is concerned with the manufacture and trade of post‐medieval crucibles (14th–19th centuries). The analytical study of crucibles from different contexts in Europe and America employed optical microscopy and SEM–EDS, coupled with archaeological and historical data. We identified two major producers of crucibles, both of them in Central Europe, whose products appear widely distributed internationally. The analytical data allow an explanation of the technical reasons behind their superior reputation, as both crucible types shared comparable material properties, such as thermal, chemical and mechanical stability. Conversely, the two crucible types were radically different in their manufacture and appearance. We argue that, besides technical considerations, sensorial aspects such as texture and colour may have played an important role in the perception and choice of materials.     

TRACING THE RESOURCES OF IRON WORKING AT ANCIENT SAGALASSOS (SOUTH‐WEST TURKEY): A COMBINED LEAD AND STRONTIUM ISOTOPE STUDY ON IRON ARTEFACTS AND ORES*

Lead and strontium isotope analyses were performed by thermal ionization mass spectrometry (TIMS) on Roman to Byzantine iron artefacts and iron ores from the territory of ancient Sagalassos (south‐west Turkey), to evaluate Pb and Sr isotopes for provenance determination of ores for local iron production. It can be demonstrated that for early Roman artefacts and hematite iron ore processed in early Roman times from Sagalassos proper, as well as for magnetite placer sands and early Byzantine raw iron from the territory of the city, Sr isotopes are much less ambiguous than Pb isotopes in providing clearly coherent signatures for ore and related iron objects. Late Roman iron objects were produced from iron ores that as yet remain unidentified. Early Byzantine iron artefacts display more scatter in both their Pb and Sr isotope signatures, indicating that many different ore sources may have been used. Our study demonstrates that iron objects can be precisely analysed for their Sr isotopic composition, which, compared to Pb isotopes, appears to be a much more powerful tool for distinguishing between chronological groups and determining the provenance of raw materials.     

ON THE AGE AND CONTENT OF JAR‐35—A SEALED AND INTACT STORAGE JAR FOUND ON THE SOUTHERN PLATEAU OF QUMRAN*

An intact and sealed storage jar known as Jar‐35 was found in 2004, south of the Qumran settlement. A previous study identified tartrate in the deposit of the jar, indicating the possible past presence of wine ( Buti et al. 2006 ). However, we cannot confirm this finding. Using liquid and gas chromatography with mass spectrometric detection, no trace of tartaric acid or salts thereof could be detected in our samples. We show that the major component of the deposit is gypsum. No other organic compounds were identified with the methods that we have applied. Both radiocarbon dating of charcoal in the deposit and thermoluminescence dating of the ceramic jar show that it dates to the main period of habitation at Qumran (c. 100 bc to ad 70).     

THE CHEMICAL COMPOSITION OF BLUE PIGMENT ON CHINESE BLUE‐AND‐WHITE PORCELAIN OF THE YUAN AND MING DYNASTIES (ad 1271–1644)*

The chemical compositions of the glazes and pigments of 39 blue‐and‐white porcelains of Ming Dynasty date and three of Yuan date were examined by SR‐XRF. Both the analysis of the Fe/Mn ratio in the light blue areas of the glaze and a comparison of the Fe/Mn values between light blue, dark blue and clear glaze areas reveals that the samples can be divided into three groups. The results indicate that there are two significant changes of provenance of blue pigment during the Ming Dynasty and that some kinds of pigment were most probably imported from the Middle East. Considering literature records and other scholars’ studies, an outline picture of the pigment used on Chinese blue‐and‐white porcelain produced in Jingdezhen in the Yuan and Ming Dynasties is presented.     

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.     

CHEMICAL–MINERALOGICAL ANALYSES AND MICROSTRUCTURAL STUDIES OF PREHISTORIC POTTERY FROM RAHMATABAD,SOUTH‐WEST IRAN*

A series of prehistoric pottery samples excavated from Rahmatabad, south‐west Iran, were investigated using XRF and XRD analyses to determine their chemical and mineralogical compositions. The sample microstructures were also studied by SEM/EDX. The relative similarity of compositions, the fine, dense and homogeneous microstructures and the presence of high‐temperature phases such as diopside and mullite showed the use of high firing temperatures, in the range 950–1050°C. This, along with the homogeneity in shape, decoration and size ranges of the ware, all indicate the adoption of specialized pottery‐making techniques by the potters of Rahmatabad in the fifth to fourth millennia bc .     

MINERALOGICAL AND PETROLOGICAL INVESTIGATIONS OF EARLY BRONZE AGE COPPER‐SMELTING REMAINS FROM THE KIECHLBERG (TYROL,AUSTRIA)

The prehistoric settlement on the Kiechlberg hilltop is located a few kilometres to the north‐east of Innsbruck, in the Tyrolean Inn Valley. Despite its rather isolated location, a multiphase settlement between the fifth and the second millennium bc was confirmed by archaeological investigations in 2007 and 2008. Metallurgical artefacts, such as copper ore fragments, copper slag and raw copper, as well as finished copper and bronze artefacts, are concentrated mainly in Late Copper Age to Middle Bronze Age layers. The chemical compositions of the slag and raw metals confirm Fe—Zn tetrahedrite–tennantite (fahlore) smelting. The ore was most probably imported from the 30–50 km distant copper ore deposits (mainly fahlore) of Schwaz–Brixlegg, in the Lower Inn Valley. The small amount of slag and the presence of slagged and thermally altered ceramic fragments suggest copper production in small‐scale workshops. Most probably, sulphide‐rich ores were smelted in crucibles in a hearth fire. The process was relatively reducing below the 2Sb + 1.5O₂ → Sb₂O₃ reaction (?8.5 log fO₂ at 1100°C), producing Sb‐rich (>10 wt% Sb in metal) raw copper. Inhomogeneous slag remains containing high amounts of sulphide and metal inclusions suggest a poor separation of the metal, matte (copper sulphide) and silicate/oxide melt during the smelting process.     

EVALUATING CONTEMPORANEITY AND POST‐MORTEM AGE OF MALACOLOGICAL REMAINS USING SCLEROCHRONOLOGY AND DENDROCHRONOLOGY*

Sclerochronology and dendrochronology are based on series of incremental skeletal and cambial growths that have been correctly aligned in time via cross‐dating (i.e., incremental dating through synchronization of the growth variability on a visual and statistical basis). Here we report a study of the shell increments of two anthropogenic death assemblages of freshwater pearl mussel (Margaritifera margaritifera) originating from Finnish Lapland. First, we cross‐dated a new sclerochronology from an assemblage of river pearl mussel shells with unknown post‐mortem age. Second, this chronology was cross‐dated with the previously published sclerochronology of the same species and geographical source. Third, the composite of the two sclerochronologies was compared to dendrochronologies from Lapland. Temporal association of the two types of chronologies was markedly high, as confirmed by t‐values of 7.1 and 8.9, which are well above the acceptable limit of 3.5. Our study demonstrates the potential of sclerochronological and dendrochronological materials and techniques in assessing the contemporaneity (i.e., temporal overlap) and post‐mortem age of archaeomalacological deposits. In the palaeontological context, these results also show the wider possibility of dating shells with a large number of annual increments from natural deposits.     

THE PETROGRAPHY AND CHEMISTRY OF THIN‐WALLED WARE FROM AN HELLENISTIC– ROMAN SITE AT SEGESTA (SICILY)*

Samples of Roman thin‐walled ware from Segesta (northwestern Sicily), dating back to the early Imperial period, were studied by optical microscopy (OM) and Neutron Activation Analysis (NAA). Up to now, this class of Roman fine tableware has only occasionally been evaluated archaeometrically. Nevertheless, numerous production centres are believed to have been simultaneously active in the western Mediterranean area. Petrographic and chemical data seem to be in agreement with the archaeological hypothesis of local manufacture in Segesta for most of the analysed samples, through a comparison with kiln wasters and local raw materials. The effectiveness of thin‐section petrography for determining the provenance of such a tiny tempered class of pottery and the integrated use of two different grouping procedures (petrography and chemistry) were also tested.     

DISCOVERY,PRODUCTION AND USE OF TIN‐BASED OPACIFIERS IN GLASSES,ENAMELS AND GLAZES FROM THE LATE IRON AGE ONWARDS: A REASSESSMENT*

Tin‐based opacifiers (lead stannate yellow and tin oxide white) were first used in glass production for a short period in Europe from the second to the first centuries bc , and then again throughout the Roman and Byzantine Empires from the fourth century ad onwards. Tin oxide was also used in the production of Islamic opaque glazes from the ninth century ad , and subsequently in enamels applied to Islamic and Venetian glasses from the 12th century ad onwards. A selection of published analytical data for the tin‐opacified glasses, enamels and glazes is summarized, and the methods used in their production are reassessed. The phase transformations occurring when mixtures of lead oxide, tin oxide and silica are fired are investigated with high temperature X‐ray diffraction (XRD) using a synchrotron radiation source, and these results are used to explain the observed differences in the glass, enamel and glaze compositions. Possible reasons for the use of tin‐based opacifiers in the second to first centuries bc , and for the switch from antimony‐ to tin‐based opacifiers in the fourth century ad are suggested, and the possible contexts in which tin‐based opacifiers might have been discovered are considered. The introduction of tin‐opacified glazes by Islamic potters in the ninth century ad is discussed in terms of technological transfer or independent invention.     

A COMBINED MULTI‐ANALYTICAL APPROACH FOR THE STUDY OF ROMAN GLASS FROM SOUTH‐WEST IBERIA: SYNCHROTRON μ‐XRF,EXTERNAL‐PIXE/PIGE AND BSEM–EDS

An integrated, multi‐analytical approach combining the high sensitivity of SR‐μXRF, the light element capability of PIXE/PIGE under a helium flux and the spatial resolution of BSEM + EDS was used to characterize chemical composition and corrosion of glass samples (first to fourth centuries ad ) from an important, but scarcely investigated, Roman region of south‐west Iberia (southern Portugal). The geochemical trends and associations of major, minor and trace elements were investigated to shed light on production techniques, the provenance of raw materials and decay mechanisms. The results, while confirming a production technique common to Roman glasses throughout the Empire—that is, a silica‐soda‐lime low‐Mg, low‐K composition, with glass additives as colouring and/or decolouring agents (Fe, Cu, Mn, Sb)—show at one site high Zr–Ti contents, suggesting a more precise dating for these glasses to the second half of the fourth century. The Ti–Fe–Zr–Nb geochemical correlations in the pristine glass indicate the presence of minerals such as ilmenite, zircon, Ti‐rich Fe oxides and columbite in the sands used as raw materials for the glass former: these minerals are typical of granitic‐type source rocks. The unusually high K content in the corrosion layers is consistent with burial conditions in K‐rich soils derived from the alteration of 2:1 clays in K‐bearing rock sequences.     

AN ARCHAEOMETALLURGICAL STUDY OF 13TH‐CENTURY ARROWHEADS AND BOLTS FROM THE CRUSADER CASTLE OF ARSUF/ARSUR

Selected iron arrowheads and bolts retrieved from the destruction layer of the Crusader castle of Arsur/Arsuf, which was taken down by the Mamluk army (headed by Baybars) in late April 1265, were studied. Being the only site within the boundaries of the Latin Kingdom of Jerusalem that has thus far yielded more than 1200 iron arrowheads, an archaeometallurgical characterization was performed. The aim of this research was to study the warfare methods and manufacturing technologies used by the Mamluk and Crusader armies. Examination included optical microscopy, SEM and SEM–EDS, XPS and microhardness tests. Analysis was performed on both the metallic iron and iron oxides. Ferrous wooden ‘fossils’, which were found on and within the bolts, were dendroarchaeologically tested. The microstructure analyses show that the weapons were made of wrought iron. These results are correlated with the function of the weapons. The different microstructures of the arrowheads and the bolts indicate dissimilar manufacturing processes. The graphitization of the ropes on the bolts and the oxide phases on their surfaces both provide evidence of high‐temperature fire. The ropes support the archaeological findings that these devices were used by the Mamluks to set the Crusader castle on fire.     

ASSESSING WHAT LIES BENEATH THE SPATIAL DISTRIBUTION OF A ZOOARCHAEOLOGICAL RECORD: THE USE OF GIS AND SPATIAL CORRELATIONS AT EL MIRÓN CAVE (SPAIN)*

Geographical Information Systems (GIS) are being incorporated into archaeology as a technique to improve the understanding of spatial organization and the relationships among finds within specific areas. Although their use as a basic tool in predicting the location of archaeological sites or in assessing the extent of their catchment areas is relatively common, in general, they have less often been applied to the study of the spatial distribution of archaeological remains within individual deposits, and in particular to faunal assemblages. Despite this, they can prove essential to understanding dispersion and grouping patterns within deposits fully, and, together with various correlation analytical techniques, they provide valuable information about the economic organization of settlements and inhabitant lifeways. To demonstrate the potential of this methodology, a zooarchaeological GIS has been prepared for the Middle and Late Magdalenian and Azilian layers in El Mirón Cave (eastern Cantabria, Spain), and the spatial distribution patterns of various attributes of the archaeological record have been analysed. Significant conclusions in terms of type and duration of human occupation have been drawn.     

DATING OF THE HOMINID (HOMO NEANDERTHALENSIS) REMAINS ACCUMULATION FROM EL SIDRÓN CAVE (PILOÑA,ASTURIAS, NORTH SPAIN): AN EXAMPLE OF A MULTI‐METHODOLOGICAL APPROACH TO THE DATING OF UPPER PLEISTOCENE SITES

The age of Neanderthal remains and associated sediments from El Sidrón cave has been obtained through different dating methods (¹⁴CAMS, U/TH, OSL, ESR and AAR) and samples (charcoal debris, bone, tooth dentine, stalagmitic flowstone, carbonate‐rich sediments, sedimentary quartz grains, tooth enamel and land snail shells). Detrital Th contamination rendered Th/U dating analyses of flowstone unreliable. Recent ¹⁴C contamination produced spurious age‐values from charcoal samples as well as from inadequately pretreated tooth samples. Most consistent ¹⁴C dates are grouped into two series: one between 35 and 40 ka and the other between 48 and 49 ka. Most ESR and AAR samples yielded concordant ages, ranging between 39 and 45 ka; OSL dating results permitted adequate bracketing of the sedimentary layer that contained the human remains. Our results emphasize the value of multi‐dating approaches for the establishment of reliable chronologies of human remains.     

MINERALOGY OF MEDIEVAL SLAGS FROM LEAD AND SILVER SMELTING (BOHUTÍN,PŘÍBRAM DISTRICT,CZECH REPUBLIC): TOWARDS ESTIMATION OF HISTORICAL SMELTING CONDITIONS*

Slags from the Pb/Ag medieval (14th century) smelting plant located at Bohutín, P?íbram district, Czech Republic, were studied from the mineralogical and geochemical points of view. Two types of slags were distinguished: (i) quenched slags formed mainly by Pb‐rich glass and unmelted residual grains of SiO₂ and feldspars, and (ii) crystallized slags mainly composed of Fe‐rich olivine (fayalite) and glass. The mean log viscosity value of the slags calculated for 1200°C was 2.119 Pa s. The morphology of olivine crystals was used to estimate the cooling rates of the melt, for some slags indicating rates > 1450°C/h. The projection of the bulk composition of slags onto the SiO₂–PbO–FeO ternary system was used for rough temperature estimates of slag formation, lying probably between 800 and 1200°C.