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.     

THE OCCURRENCE OF PALYGORSKITE IN THE YUCATÁN PENINSULA: ETHNO‐HISTORIC AND ARCHAEOLOGICAL CONTEXTS*

Palygorskite is a rare clay mineral used by the ancient Mayas for fabricating the Maya blue pigment and for other purposes. It seems to have been obtained from a restricted area in the Yucatán peninsula where important archaeological sites are found. Geological samples from different localities in this area show a high content in palygorskite, indicating that this clay is widespread in Yucatán. Combining structural, morphological, compositional and geochemical methods, we analysed the common characteristics of Yucatecan palygorskites, and compared them with palygorskites from other origins around the world. These results can be used for defining a fingerprint of Yucatecan palygorskite to be used in provenance studies of archaeological artefacts, in particular the Maya blue pigment.     

LEAD ISOTOPIC ANALYSIS OF COPPER ORES FROM THE SIERRA EL ARAMO (ASTURIAS,SPAIN)*

This study presents the first ever lead isotope ratio data for copper ore samples (malachite and azurite) from the Sierra El Aramo (Asturias, northwestern Spain). The aim of this study was to supplement information in the existing reference database on the lead isotopic composition of Spanish ores. The Sierra El Aramo is particularly important because, while no data for the Asturian ores have been published so far, this northern province of Spain has played a significant role in terms of copper exploitation and metallurgy since the Copper Age.     

A HYBRID APPROACH TO CREATE AN ARCHAEOLOGICAL VISUALIZATION SYSTEM FOR A PALAEOLITHIC CAVE

This paper presents a visualization system based on metric data to manage and disseminate archaeological information on the Internet. We describe the integration of two different types of sensors: laser scanning and close‐range photogrammetry. How we created an automatic and hierarchical approach based on processing and matching the images coming from a digital camera and a terrestrial laser scanner is also shown. This development has created a visualization system combining spherical photographs and georeferences for graphical and numerical data acquired by the sensors. The case study where we have applied this method is the Palaeolithic rock art of the Llonín Cave (Asturias, Spain), which has been declared a World Heritage Site by UNESCO and has restricted public access. Our results demonstrate that this tool integrates data, metadata, services and information, which simplifies the location, identification, selection and management of archaeological information.     

A PROVENANCE STUDY OF FRENCH LIMESTONE BASED ON VARIABLE SELECTION FROM COMPOSITIONAL PROFILES

The present study shows how multivariate analysis and variable selection techniques can be used in archaeological provenances studies to improve classification performances. Neutron activation analysis (NAA), in combination with stepwise linear discrimination analysis (SLDA) (capable of simultaneously performing variable selection and classification), was applied to differentiate among limestone samples from different quarries across the north of France based on their compositional fingerprint. A hierarchical classification approach was followed, aimed at progressively assigning limestone samples to more specific sources of origin, from the broadest classification units (French regions) to the narrowest ones (individual quarries). The application of the stepwise variable selection procedure to extract the most discriminating compositional variables prior to each classification development allowed us to obtain a perfect separation between the limestone categories considered at every classification stage (all samples were correctly classified and predicted in all cases). The high‐quality results obtained were even more remarkable considering the relatively small number of significant variables selected in each case using the SLDA method. An illustrative example was provided in order to demonstrate that the classification strategy proposed can actually allocate an unknown sculpture to a particular quarry of origin.     

THE EFFECTIVE DURATION OF EARTHQUAKE STRONG MOTION

The duration of strong ground shaking during earthquakes can play an important role in the response of foundation materials and structures, particularly when strength or stiffness degradation is encountered. A thorough seismic hazard assessment should therefore include an estimation of the expected duration of strong motion, which first requires criteria to define the part of an accelerogram considered to represent the duration of strong ground motion. Some 30 different definitions of strong motion duration are reviewed and classified into generic groups. Problems that arise with the use of these definitions for duration are highlighted. A new definition of duration is presented using a previously unexplored option which identifies the part of the record where the main energy is contained and constrains this strong shaking phase by absolute criteria. This new definition is shown to give consistently meaningful durations for strong earthquake accelerograms from an engineering viewpoint. The correlations between the new definition of duration and magnitude, soil conditions and distance are explored as a first step towards the development of predictive equations.     

PARTICLE‐INDUCED X‐RAY EMISSION (PIXE) ANALYSIS OF OBSIDIAN FROM TEOTIHUACAN

A collection of 50 archaeological obsidian samples studied in the framework of the Preciudadela Project (Teotihuacan, Mexico) has been analysed using particle‐induced X‐ray emission (PIXE) with the external beam line of the Accélérateur Grand Louvre d'Analyse Elémentaire facility (C2RMF, Paris) and of the Instituto de Física (UNAM, Mexico). This work addresses the provenance of these obsidian samples, with the purpose of determining if they come from the obsidian sources exploited by Teotihuacans (mainly Otumba and Sierra de Pachuca), from other sources, or arrived via commercial exchanges with other regions. For that, the elemental compositions derived from the PIXE spectra have been compared with data published in the literature on the basis of instrumental neutron activation analysis. From the concentrations of selected key elements (Na, K, Mn, Fe, Zn, Rb, Sr, Zr), it was possible to unambiguously assign the provenance of most samples. Many originate from two major sources, namely Sierra de Pachuca (Hidalgo) and Otumba (Mexico), which were the main obsidian deposits used by the Teotihuacans. However, some samples exhibit a compositional fingerprint matching other provenances, i.e., Paredón (Puebla) and Zacualtipan (Hidalgo).     

CHARACTERIZATION AND PROVENANCE OF LIME PLASTERS FROM THE TEMPLO MAYOR OF TENOCHTITLAN (MEXICO CITY)

In this work, we present the results of the analyses of 20 lime plaster samples taken from the Templo Mayor (Great Temple), the main pyramid of Tenochtitlan (Mexico), the ancient capital of the Mexicas. The samples were analysed to recover information on the mixtures used in the fabrication of the plasters and for the provenance of the raw materials (in particular, limestone) used to make the plasters. The characterization of the samples was done by OM, SEM/EDS, XRF and LA–ICP–MS analyses, while the identification of the provenance of raw materials was done by studying the lumps present in the samples with LA–ICP–MS. The objective of the study was to establish if there was a relationship between changes in the construction techniques employed in the pyramid over time and if there were changes in the provenance of the raw materials. Six different construction phases of this pyramid are analysed, showing the similarities and differences among them, mainly based on differences in the sieving of the aggregates and in the raw materials employed. The provenance studies of the limestone used to make the plasters demonstrated that all the limestone comes from the Tula region.