Archaeomagnetic versus luminescence methods: the case of an Early Byzantine ceramic workshop in Thessaloniki,Greece

In this contribution, we present a combined archaeomagnetic and luminescence study of archaeologically dated structures. The investigated area is a ceramic workshop comprising several Early Byzantine kilns. Based on (a) the archaeological–anthropogenic stratigraphy of the site, (b) the structural characteristics of the kilns and (c) the few ceramic findings revealed within their context, the operation of this brick and tile factory is approximately dated between the middle of the fifth century until the first decades of the sixth century AD. Three of the well-preserved workshop kilns have been studied archaeomagnetically. The full vector of the geomagnetic field, accompanied by rock magnetic analyses of the studied material, has been defined. The archaeomagnetic study revealed similar directions among the three kilns indicating and confirming their contemporary use. Additionally, several luminescence measurements were obtained on material from the same kilns. The dating of the site was performed with both methods. The archaeomagnetic dating is convergent with the archaeological estimation only when its upper limit is considered. Concerning the luminescence dating, the calculated ages (corrected for anomalous fading and for the ⁴⁰K content) with their standard deviations are convergent with the archaeological estimations for the first kiln, while for the other two, the results seem to be incompatible. The possible factors that provoked this divergence are thoroughly discussed.     

Post-depositional surface whitening of ceramic artifacts: alteration mechanisms and consequences

Surfaces on ceramic artifacts that are paler than the main sherd body are commonly interpreted as slips that were intentionally applied by the potter during the manufacturing process. However, due to post-depositional alteration, sherds that were not originally coated with a slip may macroscopically appear with deceptively similar pale surfaces. This paper presents a comparison of two sherds, both with pale to white surfaces, one of which is a real slip and the other a surficial corrosion that occurred during the burial stage. Observations using optical and scanning electron microscopy, as well as electron-probe image- and microanalysis, clearly illustrate the features of the two surfaces, as well as demonstrating their causes and effects. The superimposed slip is clearly delimited from the sherd body by a denser and much finer-grained fabric, in which clay minerals predominate and porosity is reduced by about 20% compared to the body. In the other sample, surface corrosion, due to invading fluids, has led to leaching of calcareous constituents and results in a remarkable increase in porosity close to the rim (ca. 25%). Sometimes called the “espresso crema effect” (Tschegg et al., 2009b), the surface becomes considerably brighter than the core and can easily be confused with intentional slips. This, as a consequence can lead to significant misinterpretations, to erroneous sherd characterizations and classifications, as well as to incorrect assignments to specific ware groups.     

Archaeomagnetic data from four Roman sites in Tunisia

Archaeomagnetic analyses on bricks and slag fragments from kilns have been undertaken. The initial aim of the paper was to constraint the age of four Roman sites in Tunisia (Neapolis, Pheradi Majus, Leptiminus and Sullecthum) using either archaeodirections or archaeointensities. However, the archaeomagnetic models appeared to be only proficient using directions. It has been established that the Neapolis' studied kiln was probably active until the early 6th century AD, whereas the kilns investigated in Pheradi Majus were probably active until the middle 5th century AD. Measured archaeointensities point to higher values than those predicted by the models during the whole range of possible ages for the studied sites.     

Archaeomagnetic dating of archaeological sites from Switzerland and Bulgaria

Baked materials from three archaeological sites in Switzerland and one in Bulgaria have been examined and dated archaeomagnetically. The detailed rock-magnetic properties of the burnt clay collected have already been studied therefore and have been published elsewhere (Geophysical Journal International 153 (2003) 146). The main aim of this paper is to determine the terminus ante quem for the last firing of the clay collected from pottery kilns or burnt layers. The directional and intensity results of the ancient geomagnetic field corresponding to the time of the structure's last firing are given for each site. These geomagnetic parameters are then compared with reference curves to provide archaeomagnetic dates for the last use of the kilns. Application of archaeomagnetism as a dating tool is only possible for those regions that already have reference curves. Bulgaria is fortunate in having established reference curves covering almost the last 8000 years. Two Swiss sites were dated using only directional results on the basis of existing palaeodirectional results for Switzerland as well as the French directional reference curves. The archaeomagnetic dates of three of the sites were then compared to archaeological evidence and available radiocarbon dates. The palaeointensity data obtained from this study will enrich the existing archaeomagnetic database for western Europe.     

An Archaeomagnetic Study of a Roman Bath in Southern France

Absolute Thellier–Thellier archaeointensity determinations were conducted on 137 tiles and sedimentary blocks from five different structures from the ‘Site de la Molère’, southern France, to constrain the archaeological interpretation of a relative age difference between structures and add new data to the French secular variation database. We present 89 new archaeointensity and 20 new directional results, with averages of 57 (±8) μT in the second century ad and 68 (±7) μT in the third century ad . The overall data trend is consistent with the limited available data, indicating rapidly increasing field intensity from the second to the third century ad .     

Hohokam and Patayan interaction in southwestern Arizona: evidence from ceramic compositional analyses

Ceramic raw material use is one line of evidence for prehistoric territorial boundaries and social interaction. In this paper, we characterize the raw materials used by Hohokam and Patayan potters along the western Hohokam frontier, using data from oxidation analysis, laser-ablation inductively-coupled plasma spectrometry, and petrographic analysis. The sample includes 150 sherds from three sites (AZ Z:1:29[ASM], AZ Z:1:30[ASM], and BMGR-02-F-04) south of Gila Bend, Arizona. Similar Lower Gila River sediments were used for Hohokam and Patayan ceramics during the period A.D. 700–1150. Patayan potters apparently used clay sources from an area dominated by Hohokam settlements, and their ceramics were transported at least 50 km into the desert interior, perhaps representing seasonal movements between the river and the desert.     

Archaeomagnetic dating of Dogmersfield Park brick kiln (Southern England)

Archaeomagnetic dating of samples from a brick kiln discovered at Dogmersfield Park has been achieved using both field direction and intensity. Detailed rock-magnetic properties and microwave archaeointensities have already been studied and published elsewhere [Ll. Casas, J. Shaw, M. Gich, J.A. Share, High-quality microwave archaeointensity determinations from an early 18th century brick kiln, Geophys. J. Int. 161 (2005) 653–661]. The archaeomagnetic measurements were assigned time-probability distributions by comparing with predictions from a global model at the sampling site, this procedure suppresses errors arising from relocation to a common central reference location. All three probability distributions consistently indicate the same age (∼AD 1700). Once the probability distributions are combined a narrower probability distribution is obtained, stressing the importance of pursuing combined (directional and intensity) archaeomagnetic analyses. The inferred age is also highly consistent with available historical evidence.     

A Revision to the U.S. Southwest Archaeomagnetic Master Curve

Recently, two problems have been recognized with the United States Southwest archaeomagnetic master curve (Eighmy, 1991; LaBelle & Eighmy, 1997; Sternberg, 1989). One of these problems, the damping problem, is inherent to the moving window method of curve construction proposed by Sternberg (1989). The other is due to the fact that the small number of independently dated virtual geomagnetic pole determinations available for the period between 900–1100 are not representative of secular variation during this period. The analyses presented here confirm the existence of these two problems and suggest that they distort the curve by less than 1·0° and between 1·0° and 2·0° respectively. Based on these findings, a new curve is proposed for the U.S. Southwest.     

Cross-cultural interaction on Wuvulu Island,Papua New Guinea: the perspective from use-wear and residue analyses of turtle bone artifacts

Recent studies have emphasized the importance of Indigenous producers and traders in the formation of ethnographic museum collections, but have found difficulty in finding concrete evidence for their active roles. A use-wear and residue study of turtle bone cleavers from Wuvulu Island, Papua New Guinea provides the opportunity to test whether objects that comprise a significant component of early collections were made specifically for sale, as hypothesized by contemporary observers in the late 19th century. Comparative studies of used and unused turtle bone artifacts from the Caroline Islands and Papua New Guinea identified differences between wear traces resulting from manufacture and use. Analyses of the Wuvulu turtle bone cleavers showed they had been heavily used prior to sale. Rather than produce artifacts to meet the high demand from German traders, the local people sold old, worn-out objects, many of which had been repaired. The study demonstrates that archaeological approaches to ethnographic museum collections can trace Indigenous agency within cross-cultural interaction. It also showcases the potential of use-wear and residue analytical techniques for the analysis of bone tools and the utility of digital, hand-held microscopes for the analysis of large artifacts.     

New data on relevant ancient Egyptian wooden artifacts: Identification of wooden species and study of the state of conservation with multidisciplinary analyses

Wood species identification and characterization of its weathering processes are crucial steps in the scientific approach of conservation of wooden cultural heritage. Many precious wooden objects of ancient Egypt are largely present in museums, nevertheless relatively little information is available concerning the nature of timber used and on their status of conservation. To address this gap, the wooden species of three relevant archaeological wood objects (statue, box, and coffin) arising from different Egyptian archaeological sites dated from the Old Kingdom (2,686–2,181 BC) to New Kingdom (1,550–1,069 BC) were deeply studied. Five hardwood and softwood species were identified belonging to Tamarix mannifera, T. gennessarensis, Ficus sycomorus, Vachellia nilotica, and Cedrus sp. Such data confirmed the recurrence of Vachellia and Tamarix among the most common timbers found in ancient Egypt. Scanning electron microscope, Fourier transform spectroscopy, and synchrotron x-ray radiation diffraction were conducted to evaluate the archaeological wood deterioration. The formation of microcracks, biological degradation patterns (fungal colonization), or chemical characterization (accumulation of salts on and in-between wooden cells) were detected. SEM micrographs showed the presence of fungal hyphae and conidial spores on the wooden cells. Significant changes in the chemical wood composition and decrease in the crystallinity index were detected.     

Investigating ancient technology and ceramic composition at Al-Khidr site (Failaka Island,Kuwait): Geochemical analyses of Bronze Age pottery by pXRF and thin-section petrographic analyses

Pottery assemblages from the site of Al-Khidr on Failaka Island, Kuwait, were analysed in order to reconstruct the chemical composition of Bronze Age wares and to build a mineralogical database of Bronze Age pottery dated from Failaka Periods 1–3B (2000–1650 BCE). A total of 145 ceramic sherds from Al-Khidr, as well as reference groups, were analysed by non-destructive portable X-ray fluorescence (pXRF) spectrometry. Preliminarily petrographic thin-section analysis was applied to four samples to reconstruct possible clay paste recipes and to identify raw materials. The results indicate that geochemical analyses can successfully distinguish subgroups within a typological category of ceramic assemblages. The results identified two subgroups within the Al-Khidr typological category: the Dilmun Barbar tradition and the Mesopotamian tradition. Future comparative compositional studies can be conducted to explore other aspects of craft specialisation, such as ceramic technological choices and possibly the influence of sociopolitical units.     

Bulk stable carbon and deuterium isotope analyses of bitumen artifacts from Hacinebi Tepe, Turkey: reconstructing broad economic patterns of the Uruk expansion

This research addresses issue of inter-regional trade for the world's first colonial trading system, the economic expansion of state societies from southern Mesopotamia into southwest Iran and southeast Anatolia, through the use of stable carbon and deuterium isotope analyses of bitumen artifacts. The key goal of the project was to get beyond simply the identification of trade (Schwartz, M., Hollander, D., Stein, G., 1999. Paléorient 25 (1), 67–82) and examine broad regional patterns in the exchange system. To this end, the methodological approach of this research was focused on the reconstruction of general exchange patterns using a large sample set. The results of these analyses suggest the utility of bulk isotopic analyses in the identification of broad regional patterns, serving as a complement to detailed isotopic and molecular work on asphaltene extractions of bitumen (Connan, J., Nishiaki, Y., 2003. Vol. II: Chalcolithic Technology and Subsistence. The University Museum – The University of Tokyo, Tokyo, pp. 283–306). Some of the data indicate changes in the organization of trade at the site of Hacinebi in southeast Turkey and suggest large economic changes in Anatolia associated with the Uruk expansion.     

Testing hypotheses of independence on symmetrical artifacts

Independence between attributes on artifacts with two equivalent loci has ordinarily been tested only when the loci can be differentiated from each other, say as left or right side or as distal or proximal end. If such an identification does not exist, is uncertain or is irrelevant, then a test of independence requires a special statistical procedure. Such a procedure is given here. Applications are illustrated for coreplatforms, geometric microliths and arrow-head typology, and an extension to artifacts with several equivalent loci is determined.     

Metallurgical analysis of copper artifacts from Cahokia

Copper artifacts from Cahokia Mounds, Illinois were analyzed from a materials science perspective to shed light on techniques used by Mississippian copper workers to deform nuggets of native copper into thin sheets. Eight small copper pieces from a copper-working site at Cahokia’s Mound 34 were subjected to metallographic examination. Replication experiments thereafter recreated features of the artifacts under controlled conditions. It is concluded that copper sheets were thinned through repeated cycles of hammering and annealing performed at temperatures achievable in an open wood fire. The welding of sheets to create multilayered objects was not observed in any artifacts and could not be accomplished experimentally. Additionally, a possible cutting method used on some artifacts was identified.     

Conservation of artifacts: A question of survival

Historical Archaeology - Archaeological materials recovered from earth or water have become altered physically, chemically, or biologically through time and intereaction with their burial...     

Recent developments in the analysis of lithic artifacts

A review of recent research on lithic technology and functional analysis is presented. Our perception of the state of the art is based on a review of the literature published during the past three years and on the topics that were covered at conferences and workshops on lithic analysis. While the goals have essentially remained the same since the turn of the century, concerns with chronology and the classification of lithic artifacts have given way to studies that treat stone implements as products of a dynamic system of human behavior. In order to understand stone artifacts and the people that made and used them, archaeologists must understand theprocesses involved in the acquisition, production, exchange, and consumption of lithic artifacts. In the past ten years, experimental studies involving the manufacturing and use of stone tools have been integrated with studies of refitted or conjoined lithic artifacts and microwear analysis. The result is a much more dynamic view of the variability in assemblages of lithic artifacts. In this review, we focus on replication and technological analysis of chipped stone artifacts and microwear analysis, and consider the implications of this research.     

The analysis of copper artifacts of the copper inuit

Metallography and neutron activation analysis have been used to investigate copper artifacts from 19th century archaeological sites associated with the “Copper Inuit” of the west-central Canadian Arctic. A knowledge of the source of the copper from which the artifacts were manufactured - native (local) copper or European (exotic) copper - is important, for example, to studies of the effects of European contact on utilization of native copper and on the general lifestyle of the Copper Inuit. Trace element analysis by neutron activation using the SLOWPOKE reactor has allowed local native copper, from the Coppermine River and Victoria Island, NW Territories, to be clearly distinguished from 19th century European smelted copper, which was found to contain higher concentrations of arsenic, antimony, nickel and selenium. Moreover, optical and scanning electron metallography revealed significant microstructural differences between native copper and the 19th century smelted copper. As a consequence it was possible to differentiate between native copper archaeological artifacts and those produced from smelted copper.     

海底打捞铁质文物的腐蚀机理及其脱氯方法

综述了铁质文物在海水中及打捞出水后的腐蚀机理,如电化学循环机理、氧浓差电池腐蚀机理等,同时简述了从海水中打捞出来的铁质文物的各种脱氯方法,包括碱性溶液浸泡法、碱性亚硫酸盐还原法,电解还原法及高温还原法等.