Oxalate Patinas on Stone Monuments in the Venetian Lagoon: Characterization and Origin

Calcium oxalate patinas have been sampled on architectural elements of two ancient churches located on Torcello Island (Venetian Lagoon) and subsequently analyzed. The site had been selected presenting patinas of exceptional amount and thickness, elsewhere generally found as thin alteration layers covering stone surfaces or within black crusts on monuments in urban environments. Optical and mineralogical analyses suggest that these patinas are not the result of a simple deposition process, but originate as surface “transformations” of the substrate, and are mainly composed of dihydrate calcium oxalate (weddellite) and gypsum. Among the experimental techniques, isotope analyses (C and S) have been specifically carried out aiming at achieving a better understanding of their origin and possible causes of formation. The observed carbon isotopic fingerprint reveals in fact a strong biological fractionation recorded in the oxalate patina (δ¹³C ranging from ?22.3‰ to ?28.0‰), almost exclusively attributable to C3 pathway photosynthesis processes. Slightly negative sulfur isotope ratio values seem to be inversely correlated with patina exposure to atmospheric agents and pollutants. The results obtained prove that calcium oxalate originates from a biomineralization process induced by lichen colonization in specific environmental conditions.     

Stabilization of the Tlaltecuhtli monolith pigments

A painted monolith, as important as the Aztec Calendar or the Coyolxauhqui, has been discovered in the ritual Aztec center of Mexico City. It represents Tlaltecuhtli, the bisexual manifestation of the Earth from whom all life comes. Still, pigments, which have lost their conglomerating resins, have to be retained. In this study, the consolidation of ochre pigment on original fragments from the Aztec sculpture is presented. Several compounds were tested as consolidants, on the one hand natural polysaccharides, Funori and Slobber of Nopal exudate, on the other derivatives of cellulose, Methocel^® and Klucel^®, and also commercial consolidants as KSE 300^® and Paraloid B72^®. To simulate the ageing of consolidated samples, they were treated in an Accelerated Weathering Tester. Then, both sets of samples, fresh and aged, were characterized structural, morphological and texturally by using X-ray diffraction, electronic microscopy and nitrogen adsorption, respectively. A leaching test was performed on consolidated samples to evaluate the consolidant efficiency.     

Use-wear analysis of an Amudian laminar assemblage from the Acheuleo-Yabrudian of Qesem Cave,Israel

In this paper the results of use-wear analysis of an Amudian lithic assemblage recently discovered at Qesem Cave, Israel, are presented. Although very old, this assemblage maintains well-preserved traces of use that indicate that butchering activities and plants collecting were carried out at the site. Cut marks on faunal remains confirm the observations obtained by use-wear analysis.     

Review of Archaeological Research in Angola

This article examines the historical processes that shaped the development of archaeological practice in Angola during the Portuguese colonial period and the aftermath of political independence. Using published works, unpublished reports, and photographic records, we examine the research themes, actors, scholars, and institutions that influenced archaeological research in the country. We also used documents and museum collections in Angola and Portugal to create a GIS database of Angola’s archaeological findings. This study highlights the events, personalities, and priorities that motivated earlier investigations, and the geographical distribution of prehistoric sites. We hope this study will be a resource for guiding future archaeological research in Angola.

     

Cultural Barriers to Activist Networking: Habitus (In)action in Three European Transnational Encounters

Transnational coordination is a key aspiration of activists seeking to mobilize globally, yet the literature pays insufficient attention to the impact of cultural differences on transnational networking. In this article I draw on ethnographic data from three European autonomous social movement encounters in the Global Justice Movement (2002–2004) to demonstrate the impact of culture clashes between activists on transnational networking. I use the concept of habitus to explore how routinized, taken for granted, symbolic systems of meaning that individuals from shared locations have in common shape their interactions in transnational encounters. This conception of culture is underutilized in social movement analysis yet offers important insights into internal movement dynamics. I argue that despite the autonomous commitment to radical openness and plurality, a lack of attention to the empirical reality of place‐based activist subcultures and habitus actually works against the “cosmopolitanism” that many activists and scholars aspire to.     

The Evolution of Population Distribution on the Iberian Peninsula: A Transnational Approach (1877–2001)

Abstract

Surpassing the national perspective usually adopted, the authors confirmed the existence of a pattern of population distribution common to the whole Iberian Peninsula in the long run. This pattern is clearly associated with geographical factors. These variables seem to have more weight in explaining changes between 1877/78 and 1940 than in the period from 1940 to 2001. The observation of the cross-border region has shown that proximity to the frontier has not generated any distinct pattern of population density on either side of the boundary line. The spatial coherence of the observed phenomena throughout the Peninsula and of its evolution, independent of the border between states, reinforces the importance of geographic factors in their explanation. At the same time, this verification opens up new issues related to the effect of national political and economic policies.     

Palaeoenvironmental reconstruction of La Olla,a Holocene archaeological site in the Pampean coast (Argentina)

The evolution of littoral palaeoenvironments in the southern Pampas region of Argentina towards the end of the early Holocene and the beginning of the mid Holocene is discussed, and the formation processes of the archaeological site of La Olla are analysed. This site is located in the intertidal zone of the present beach and is remarkably well-preserved. The human occupation at the site has been dated at between 7400 and 6480 yrs BP, and is interpreted as a place for the processing and consumption of the southern fur seal (Arctocephalus australis) and southern sea-lion (Otaria flavescens). It is concluded that biostabilization by microbial mats of the sedimentary structures and archaeological remains that developed and are present on the tidal flat prevented their erosion by wind, turbulence currents and waves. This is what has permitted the exceptional preservation of the site. On the basis of the analyses of one of the sectors of the site it can be concluded that the sedimentary succession of the La Olla site is the result of the coastal environmental changes during the early–mid Holocene in the pre-maximum transgressive episode. During this interval a tidal flat developed on the Pleistocene abrasion platform. Human occupation occurred during the formation of mixohaline marsh, an upper intertidal–lower supratidal zone ecosystem.     

Funerary practices and kinship in an Early Bronze Age society: a Bayesian approach applied to the radiocarbon dating of Argaric double tombs

The main aim of this paper is to test the hypothesis on kinship relations (affinity/marriage vs descent/consanguinity, and matrilocality) expressed in the funerary record of the El Argar Bronze Age society (South-east Iberia, 2200–1550 cal BCE), taking into account the absolute chronological dimension of double adult tombs. A set of 23 double tombs having radiocarbon dates for both skeletons were selected, and radiocarbon calibration and Bayesian probability analysis was conducted. The results support the ‘descent’ hypothesis, since for most of the cases the chronological distance between individuals buried together was larger than two decades. Finally, several guidelines for future research are suggested in order to overcome shortages in current chronological and archaeological data.     

Egyptian Blue cakes from the Ayanis fortress (Eastern Anatolia,Turkey): micro-chemical and -structural investigations for the identification of manufacturing process and provenance

The microstructure and chemical composition of blue cakes, found during the archaeological excavation of the Ayanis fortress (Eastern Anatolia, Turkey), have been investigated by means of scanning electron microscopy combined with energy dispersive spectrometry (SEM–EDS), X-ray diffraction (XRD), micro-Raman (μ-Raman) and optical microscopy (OM) techniques. The analysis of the Ayanis cakes has shown the presence of Egyptian blue (i.e. CuCaOSi₄O₁₀, cuprorivaite), as the major component, intermixed with minor amount of other phases such as partially reacted quartz grains, an adherent glass phase and copper oxides. Since the finding of Egyptian Blue in Turkey has been never reported so far, great attention has been paid to its characterisation. The micro-chemical and micro-structural investigations of the Ayanis cakes have allowed a further insight into the manufacturing process and into the sources of the starting materials. The results of the characterisation have revealed some significant differences with respect to Egyptian blue cakes found in Egypt and Mesopotamia, as for instance the absence of tin excluded the use of bronze scraps or filings in their preparation differently from those produced in Egypt and Mesopotamia. Furthermore, some peculiarities of Egyptian blue found in Ayanis, as the detection of zinc in the cakes, allow to put forward the hypothesis of a local production considering that a large part of the bronze artefacts found at the Ayanis fortress is characterised by the presence of zinc as minor alloying element.