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 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.     

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.     

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.     

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.     

Computer-based,automatic recording and illustration of complex archaeological artifacts

We report on the development of a computerized automatic system to illustrate complex archaeological objects. The illustrations are based on 3D scans of the artifacts. The 3D models can be automatically translated, by new algorithms specifically designed for this purpose, into 3D or 2D line drawings; into colored images that emphasize the salient shape attributes of the artifacts and of the 3D designs on them; and to images that enhance faint/eroded designs that are otherwise difficult to discern. These illustrations are intended to replace traditional, manual drawings, which are very expensive to produce and not accurate enough. Our illustrations also provide a better visualization tool than the 3D models themselves. Though 3D scanning already improves the visibility of objects and their features, it does not suffice for rapid visual recognition. Our system generates efficient, objective, accurate and simplified representations of complex objects and the designs on them from any number of required views.     

Investigating the production provenance of iron artifacts with multivariate methods

The quest for suitable data, data treatments and statistical methods for identifying the provenance of iron artifacts has led to a variety of analytical strategies. Researchers working on the problem have been slow to develop or adopt the use of multivariate statistical techniques, despite their successful implementation in other archaeomaterials sourcing frameworks. This paper explores the analytical potential of a comprehensive multivariate statistical strategy for identifying the primary production origins of bloomery iron artifacts using bulk chemical analyses of bloomery smelting slag and slag inclusions in iron artifacts. This strategy includes a multivariate model for identifying distinct slag inclusion types introduced during smelting and refining. Principal component analysis and linear discriminant analysis are then applied to smelting slag training sets to create multivariate provenance fields, the chemical distributions of which are defined by kernel density estimation. Single and multi-group evaluation methods are examined. Appropriate data transformations are discussed to facilitate the projection of the chemistry of “unknown” slag inclusions into the multidimensional space generated by the smelting slag groups of known provenance. The efficacy of this strategy is demonstrated through its application to a previously examined data set derived from three iron production experiments and a published archaeological example. Results indicate that an appropriately designed multivariate strategy can be an effective tool for evaluating provenance hypotheses for bloomery iron artifacts.