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7 December 2016
, Pages 232-249
Rock crystal appears relatively frequently in Late Prehistoric Iberian sites, especially in the form of micro-blades and knapping debris. With some exceptions, however, these finds have seldom been looked into in any detail, and therefore little is known about the technology involved in the use of this material, its social and economic relevance or its symbolic significance. In this paper we examine a collection of rock crystal artefacts recently found at Valencina de la Concepción (Seville, Spain), one of the largest 3rd millennium BC sites in Western Europe. Among the objects included in this study are a long dagger blade, twenty-five arrowheads and a core, all of which form the most technically sophisticated and esthetically impressive collection of rock crystal material culture ever found in Prehistoric Iberia. Through the analysis of the procedures and techniques applied in the production of these objects, the chemical characterisation of the raw materials through Raman spectroscopy and RTI image processing and the careful assessment of the archaeological contexts in which they were found, this paper makes a robust contribution towards the study of the role of rock crystal in Copper Age technology and society. Recent research suggest that Valencina was a major node in the circulation of exotic materials such as ivory, amber, cinnabar or flint in Copper Age Iberia, which provides a very good background to assess the relevance of rock crystal as a traded commodity. In addition we discuss the role of rock crystal as a marker of status in large megalithic monuments, as well as its possible symbolic connotations.
In prehistoric Europe, lithic utensils were largely made from varieties of cryptocrystalline sedimentary rock or other rocks with conchoidal fracture. Knapping of minerals such as rock crystal was less prevalent, due to their anisotropic structure. The term ‘rock crystal’ is applied to a monocristal which is as variety of macro-crystalline quartz characterised by its hyaline appearance and ordered atomic structure, which determines specific knapping methods, following its internal structure (Crabtree, 1968: 10–11; Novikov and Radililovsky, 1990, Mourre, 1994, Inizan etal., 1999: 19–23). In some European regions the exploitation of rock crystal may have been caused by the dearth of flint (Aubry and Igreja, 2009), although it has been observed that its exploitation could also be explained by its physical properties and symbolic value (Reher and Frison, 1991, Taçon, 1991, Sachanbiński etal., 2008). The limitations inherent to the manufacture of rock crystal objects in comparison with objects made from other raw materials are reflected in the reduced size of the knapped objects, their low level of standardisation and the particular features of the chaîne opératoire involved – including the frequent use of uncontrolled knapping on an anvil (Peña and Wadley, 2014). Nonetheless, a technique for working with rock crystal which overcame the aforementioned limitations was developed during Late Prehistory in certain European regions. This was the case of the south-west of the Iberian Peninsula in the third millennium BCE.
Not as much research into the use of rock crystal in Iberian Late Prehistory has been carried out as into other exotic materials, such as variscite, ivory and amber. Since the 1980s a handful of articles (for example Fábregas Valcarce, 1983, Fábregas Valcarce and Rodríguez Rellán, 2008, Forteza González etal., 2008) as well as numerous references in excavation reports and studies of lithic technology have noted the importance of this raw material. However, it was not until a recent synthesis was published (Costa Caramé etal., 2011) that we began to acquire a general idea of its importance in the fourth and third millennia BCE, a period in which it was valued particularly highly and would seem to have been very socially significant. According to this synthesis, in the Spanish southwest (regions of western Andalusia and Extremadura - a territory with an area of 129,902km2) rock crystal items have been found in 33 different structures, mostly megalithic monuments (Table1, Fig.1). Some items came from tombs of the same necropolis. For a further five sites, items more vaguely described as “quartz crystals” (and others) are mentioned that could allude to rock crystal (Costa Caramé etal., 2011). The vast majority of these structures only contained one or two objects, with a few exceptions, such as the dolmens of Lanchas I (Valencia de Alcántara, Cáceres), El Corchero (also in Valencia de Alcántara), and Ontiveros (Valencina de la Concepción, Seville), in which 15, 12 and 16 arrow heads were found respectively, as well as the Cuesta de Los Almendrillos megalith (Ardite, Málaga), from which 10 micro-blades were collected. From a functional viewpoint, rock crystal appears in these contexts either in its natural form, with very little or no processing (which is the case with nodules, monocrystals and prisms), as arrowheads or, more commonly, as micro-blades and small extraction cores (Costa Caramé etal., 2011: 261). The only exceptions to this general rule are two perforated beads from Los Millares (Almería) and two more from Las Lanchas I and Datas II megaliths respectively (both belonging to the megalithic site of Valencia de Alcántara, in Cáceres). This suggests that in Iberian Late Prehistory there were well defined patterns for selecting raw materials according to the use or function they would be given. Stones such as variscite and amber seem to have been exclusively used to make body ornaments, whereas rock crystal was predominantly used to manufacture arrowheads and micro-blades, although quartz monocrystals and prisms were used in their ‘natural’ state, perhaps as personal, apotropaic objects (such as amulets or charms). In the Palacio III megalithic funerary complex (Almadén de la Plata, Seville), a set of monocrystals, prisms and nodules of various types of quartz, which had not been (or hardly had been) processed, were identified: they were interpreted as amulets, talismans, charms or even heirlooms (Forteza González etal., 2008). The only piece of rock crystal in the Palacio III burial complex was a micro-blade (Forteza González etal., 2008).
The empirical evidence regarding the provenance of the rock crystal and quartz found in these megalithic monuments is very scarce. We can mention the analysis of the magnificent smoky quartz monocrystal found in the dolmen of Alberite (Villamartín, Cádiz), for which a non-local origin connected with the pegmatite rock deposits located in the igneous massifs of the Spanish Central System was suggested (Domínguez-Bella and Morata Céspedes, 1995: 141). In the Palacio III megalithic complex, the monocrystals found in the tholos (ornaments 4 and 5) were both classified as belonging to the milky variety, which is translucent (i.e. not transparent and with white colour), and interpreted as relatively rare specimens that were difficult to obtain. This would mean they were likely to have been traded at a supra-local level, but a concrete place of origin could not be established. Additionally, of the pieces from the Iron Age collection found in the gallery dolmen of the Palacio III megalithic complex, the prase quartz crystal (piece no.2) is an extraordinarily exotic specimen (even exceptional from a crystallographic perspective) and therefore, in all probability, would have been a highly prized and valuable object due to its rarity. Locations at Llerena or Malpartida de la Serena (Badajoz), or even certain mining areas in the south-east of Córdoba were suggested as potential places of origin for these items (Forteza González etal., 2008: 148–149; Murillo-Barroso etal., 2015a: 328–329).
In view of the relative frequency with which quartz and rock crystal appear in southern Iberian (collective) funerary contexts of the 4th and 3rd millennia BCE, their disappearance from such contexts (both individual and collective), in the Early Bronze Age (from the beginning of the 2nd millennium BCE), is truly striking. It would seem that, between the end of the 3rd and the beginning of the 2nd millennia BCE the use of this raw material as grave goods was almost entirely abandoned.
This article is intended as a contribution into the research ofrock crystal use among the communities of Copper Age southern Iberia. The starting point for this study is a remarkable set of unpublished objects from the Chalcolithic site of Valencina de la Concepción (Seville). Among these are a dagger blade, 15arrowheads and a core found in two major megalithic monuments, plus other smaller items found in non-megalithic structures. Because of their size and technical characteristics, both the dagger blade and the core are unique specimens in thearchaeological record of Late Prehistoric Iberia. Their techno-morphological, geochemical and contextual analysis throws newlight on the use and social significance of rock crystal, asubject on which little research had been previously carried out.
The settlement of Valencina de la Concepción-Castilleja de Guzmán (henceforth Valencina), is located in the lower Guadalquivir valley, within the metropolitan area of Seville. Valencina is one of the largest (around 450ha) and most significant sites for the study of Copper Age Iberia. In the last few years, various publications have given international dissemination to the research being carried out in this site, providing new ideas and valuable data related to key aspects of third millennium
Core and micro-blades
On a quantitative level, the presence of knapped rock crystal objects in southern Iberia Peninsula is better represented by small cores and micro-blades extracted by pressure knapping. Given its large size, the core deposited in the Montelirio tholos (Fig.5, Fig.6, Fig.7) is therefore an extraordinary find. The core, used for the extraction of small blades, is supported naturally by a hexagonal rock macrocrystal, four of whose faces are recognisable. The extractions were prepared through
Geochemical analysis through Raman has been carried out on three of the items: the core and one arrow head fragment from the Montelirio tholos and the dagger blade from PP4-Montelirio. Two are indicative of larger rock macrocrystals. Given that a larger set of objects was found in the Montelirio tholos, the same process has been applied to a arrow head found in this tomb in order to establish whether it could match the core found in the same tomb.
All three items analysed contain some evidence
Singularity of the technological process
Lithic technology achieved a high mark in the southern Iberian Copper Age (Nocete Calvo etal., 2005, Morgado etal., 2011, Morgado and Pelegrin, 2012). Specialisation is not only reflected in the exploitation of minerals carried out by certain communities with access to the region's best outcrops of siliceous rock (Ramos Millán etal., 1997, Linares Catela etal., 1998, Morgado and Lozano, 2011), but also by the development of complex production systems involving specific knapping methods and
We would like to thank Juan Manuel Vargas Jiménez and Ana Pajuelo Pando for the information they kindly provided regarding the excavated areas in IES, as well as García Lorca and Dinamarca streets. We also give our thanks to Ana Navarro Ortega, director of the Archaeological Museum of Seville, for enabling us to examine and photograph the pieces included in this study. This research was carried out within the research project “Study of the PP4-Montelirio Sector of Valencina de la Concepción,
- M. Murillo-Barroso et al.New objects in old structures: the Iron Age hoard of the Palacio III megalithic funerary complex (Almadén de la Plata, Seville, Spain)
Journal of Archaeological Science
- J.A. Afonso Marrero et al.
Objects in exotic raw materials and the hierarchical structure of the tombs in the Los Millares necropolis (Santa Fe de Mondújar, Almería, Spain)
- P. Arias Cabal et al.
El puñal de sílex calcolítico de La Garma (Omoño, Cantabria). Sautuola
Revista del Instituto de Prehistoria y Arqueología Sautuola
- M. Almagro Basch et al.
El Poblado y la Necrópolis Megalíticos de Los Millares (Santa Fe de Mondújar, Almería)
- J. Baena Preysler et al.
Más allá de la tipología lítica: lectura diacrítica y experimentación como claves para la reconstrucción del proceso tecnológico
- M. Brandl et al.
Contemporary rock crystal mining in Minas Gerais, Brazil: an ethno-archaeological case study
- P. Bueno Ramírez
Los Dólmenes de Valencia de Alcántara
- R. Cabrero García
El Fenómeno Megalítico en Andalucía Occidental
- L.M. Cáceres Puro et al.
Marine bioerosion in rocks of the prehistoric tholos of La Pastora (Valencina de la Concepción, Seville, Spain): archaeological and palaeoenvironmental implications
Journal of Archaeological Science
- J. de M. Carriazo y Arroquia
El dolmen de Ontiveros (Valencina de la Concepción, Sevilla)
El dolmen de Hidalgo (junto a la desembocadura del Guadalquivir) y las contiguas sepulturas en fosa eneolíticas
Les cristaux de roche du tertre et de la tombe
Los sepulcros megalíticos de Huelva. (Excavaciones arqueológicas del Plan Nacional 1946–1952)
Exemples tourangeaux de sciage des roches au Néolithique
Bulletin de la Société Préhistorique Française
The Copper Age settlement of Valencina de la Concepción (Seville, Spain): demography, metallurgy and spatial organization
Trabajos de Prehistoria
Artefacts produced in rare rocks from funerary contexts of the 4th–2nd millennia cal BCE in southern Spain: a review
Craft specialization: issues in defining, documenting and explaining the organization of production
Craft production systems
The mechanics of flaking
Mesoamerian polyhedral cores and prismatic
Le Sciage des Roches Tenaces au Nord-Ouest des Alpes (4300–2450 av. J.-C.)
Précis de Dessin Dynamique et Structural des Industries Lithiques Préhistoriques
Lithic resources in the early prehistory of the Alps
Soto, un ejemplo de arte megalítico al Suroeste de la Península
Aplicación de las técnicas mineralógicas y petrológicas a la arqueometría: Estudio de materiales del Dolmen de Alberite (Villamartín, Cádiz)
Productos arqueológicos exóticos en los contextos de los yacimientos prehistóricos de la banda atlántica de Cádiz. Inferencias de su documentación
Practical Raman spectroscopy
El Chamanismo y las Técnicas Arcaicas del Éxtasis
Enterramientos de la Edad del Bronce del Cerro del Berrueco (Medina Sidonia, Cádiz)
Los prismas de cuarzo en la cultura megalítica del Noroeste de la Península Ibérica
Gestión del cuarzo y la pizarra en el Calcolítico peninsular: el santuario de El Pedroso (Trabazos de Aliste, Zamora)
Trabajos de Prehistoria
Montelirio: Un sepulcro clave para la comprensión del registro de los grandes monumentos megalíticos de Valencina de la Concepción-Castilleja de Guzmán (Sevilla)
Avance al estudio del sepulcro megalítico de la Cuesta de los Almendrillos de Ardite, Alozaina (Málaga)
Apalaeodietary study of stable isotope analysis from a high-status burial in the Copper Age: the Montelirio megalithic structure at Valencina de la Concepción-Castilleja de Guzmán, Spain
International Journal of Osteoarchaeology
Production and Exchange of Bifacial Flaked Stone Artifacts during the Portuguese Chalcolithic
El cuarzo como material votivo y arquitectónico en el complejo funerario megalítico de Palacio III (Almadén de la Plata, Sevilla): análisis contextual y mineralógico
Trabajos de Prehistoria
Sacred work: dedication and termination in Mesoamerica
Une approche anthropologique de la notion de bien de prestige. Bulletin d'Études Préhistoriques et Archéologiques Alpines (Aoste) 21
Las mineralizaciones de litio asociadas al magmatismo ácido en Extremadura y su encuadre en la Zona Centroibérica
El asentamiento de la Edad del Cobre de Valencina de la Concepción: estado actual de la investigación, debates y perspectivas
Social complexity in Copper Age southern Iberia (c. 3200–2200calBC): reviewing the ‘state’ hypothesis at Valencina de la Concepción (Seville, Spain)
Ivory craftsmanship, trade and social significance in the southern Iberian Copper Age: the evidence from the PP4-Montelirio sector of Valencina de la Concepción (Seville, Spain)
European Journal of Archaeology
El sepulcro megalítico del Cortijo de la Mimbre (Alpandeire-Málaga)
Excavaciones en Niebla (Huelva): El Tholos de El Moro
El Lenguaje de la Diosa
Le travail de la fibrolite en Armorique
Bulletin de la Société Préhistorique Française
Torre Melgarejo, un sepulcro de inhumación colectiva en los Llanos de Caulina (Jerez, Cádiz)
Memoria y mapa geológico y de recursos minerales del sector centro-occidental de Extremadura (escala 1:100.000)
Un avance de la excavación del sepulcro megalítico de El Juncal (Ubrique, Cádiz)
Revista Atlántico Mediterránea de Prehistoria y Arqueología Social
- “Other” possibilities? Assessing regional and extra-regional dental affinities of populations in the Portuguese Estremadura to explore the roots of Iberia's Late Neolithic-Copper Age
2017, Journal of Archaeological Science: Reports
The relationship between the development of social complexity in the Iberian Peninsula during the 4th and 3rd millennia BCE (Late Neolithic and Copper Age) and population movement has been a longstanding question. Biological affinity analyses were used to explore Iberian demographic dynamics, and specifically, to discern whether there is evidence for migration and gene flow between northwest African, eastern Mediterranean, and Iberian populations. Affinities based on comparisons of nonmetric traits from the Arizona State University Dental Anthropology System were estimated among samples of burial populations from three key Late Neolithic-Copper Age sites in the Portuguese Estremadura: Cova da Moura (3700–2300BCE), Bolores (2800–2600BCE), and Pai Mogo I (2800–2600BCE). Results indicate: 1) the possibility of genetic exchange with African and other Mediterranean peoples, 2) some measure of population continuity over time in the Estremadura, and 3) possible local isolation of populations, given distinctive patterning at the site of Pai Mogo, located 23km north of Cova da Moura and Bolores.
- Quartzes matter. Understanding the technological and behavioural complexity in quartz lithic assemblages
2016, Quaternary International
Crafting Idiosyncrasies. Early Social Complexity, Ivory and Identity-Making in Copper Age Iberia
2022, Cambridge Archaeological Journal
A Prehistoric Rock Crystal Procurement Site at Fiescheralp (Valais, Switzerland)
2021, Lithic Technology
A New Perspective on Copper Age Technology, Economy and Settlement: Grinding Tools at the Valencina Mega-Site
2020, Journal of World Prehistory
Fluorite and translucent beads in Iberian Late Prehistory
2020, Materials and Manufacturing Processes
Research articleQuartz and silcrete raw material use and selection in late Holocene assemblages from semi-arid Australia
Quaternary International, Volume 424, 2016, pp. 12-23
Both quartz and silcrete cobbles are abundant in the stony desert regions of western New South Wales, Australia and were used by Aboriginal people who occupied these regions from the mid to late Holocene. Archaeologists often characterise quartz as an inferior material for flaking when compared to silcrete, but Aboriginal people made intensive use of both materials. Here, we investigate the degree to which archaeologists can draw inferences about the choices people made in the past regarding the selection and use of different raw materials. Different types of raw material (i.e. microcrystalline silcretes and macrocrystalline quartzes) were flaked more or less intensively, but it is the utilization of the products of this flaking, not simply their manufacture, that allows inferences to be made about past intentions.
Research articleQuartzes matter. Understanding the technological and behavioural complexity in quartz lithic assemblages
Quaternary International, Volume 424, 2016, pp. 2-11
Research articleVariability of the rebound hardness as a proxy for detecting the levels of continuity and isotropy in archaeological quartz
Quaternary International, Volume 424, 2016, pp. 191-211
The Equotip Hardness Tester is applied to different types of quartz and other lithic raw materials in order to determine if variations in the rebound hardness measured by this device may serve as a proxy for detecting the levels of continuity and isotropy of toolstones. Continuity, the amount of cracks and other internal defects; and isotropy, the measure of the directional properties of a raw material, are known to have important effects on the level of consistency and predictability of fractures, which in turn is traditionally considered a main factor for defining the flaking quality of a given raw material.
The results demonstrate the existence of differences among the raw materials analysed in both the average value and the variability of the rebound hardness. While cryptocrystalline samples show the most homogeneous results, quartz and metamorphic rocks display a comparatively higher variance. In the specific case of quartz, such variability seems to be mainly caused by the presence of internal planes and discontinuities, while anisotropy, although also active, had played a comparatively modest role. The results achieved by the Equotip Hardness Tester suggest that this device could be successfully used for a basic or preliminary estimating of some of the physical and mechanical properties of stone raw materials. Therefore, it is a potential index test for complementing other, more accurate, laboratory methods.
Research article“Carbon Bombs” - Mapping key fossil fuel projects
Energy Policy, Volume 166, 2022, Article 112950
Meeting the Paris targets requires reducing both fossil fuel demand and supply, and closing the “production gap” between climate targets and energy policy. But there is no supply-side mitigation roadmap yet. We need criteria to decide where to focus efforts.
Here, we identify the 425 biggest fossil fuel extraction projects globally (defined as >1 gigaton potential CO2 emissions). We list these “carbon bombs” by name, show in which countries they are located and calculate their potential emissions which combined exceed the global 1.5°C carbon budget by a factor of two. Already producing carbon bombs account for a significant percentage of global fossil fuel extraction. But 40% of carbon bombs have not yet started extraction.
Climate change mitigation efforts cannot ignore carbon bombs. Defusing them could become an important dimension of climate change mitigation policy and activism towards meeting the Paris targets. So far, few actors, mainly from civil society, are working on defusing carbon bombs, but they are focussing on a very limited number of them. We outline a priority agenda where the key strategies are avoiding the activation of new carbon bombs and putting existing ones into “harvest mode”.
Research articleIntake of fruits and vegetables according to pesticide residue status in relation to all-cause and disease-specific mortality: Results from three prospective cohort studies
Environment International, Volume 159, 2022, Article 107024
Intake of conventionally grown fruits and vegetables (FVs) is an important route of exposure to pesticide residues in the general population. However, whether health risk stemming from exposure to pesticides through diet could offset benefits of consuming FVs is unclear.
We assessed the association of FV intake, classified according to their pesticide residue status, with total and cause-specific mortality.
We followed 137,378 women (NHS, 1998–2019, and NHSII, 1999–2019) and 23,502 men (HPFS, 1998–2020) without cardiovascular disease, cancer, or diabetes at baseline. FV intake was assessed using validated food frequency questionnaires and categorized as having high- or low-pesticide-residues using data from the USDA Pesticide Data Program. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI) for total and cause-specific mortality associated with high- and low-pesticide-residue FV intake.
A total of 27,026 deaths, including 4,318 from CVD and 6,426 from cancer, were documented during 3,081,360 person-years of follow-up. In multivariable-adjusted analyses, participants who consumed≥4 servings/day of low-pesticide-residue FVs had 36% (95% CI: 32%-41%) lower mortality risk compared to participants who consumed<1 serving/day. The corresponding estimate for high-pesticide residue FV intake was 0.93 (95% CI: 0.81–1.07). This pattern was similar across the three most frequent causes of death (cardiovascular disease, cancer and respiratory diseases).
High-pesticide-residue FV intake was unrelated whereas low-pesticide residue FV intake was inversely related to all-cause mortality, suggesting that exposure to pesticide residues through diet may offset the beneficial effect of FV intake on mortality.
Research articleMicrowear features on vein quartz, rock crystal and quartzite: A study combining Optical Light and Scanning Electron Microscopy
Quaternary International, Volume 424, 2016, pp. 154-170
In general, quartz and most of non-flint rocks have not been extensively studied from a functional point of view. Very frequently the definitions of micro-features connected with flint surfaces have been used to describe those encountered on non-flint tools. This circumstance has repeatedly posed serious methodological problems for evaluating the accuracy of functional results when analysing use-wear on quartz and quartzite implements. This is due to the intrinsic divergences in morphology and distribution of use-wear with regard to the different lithic raw materials.
Even though important efforts to systematise use-wear features on quartz have been done almost since the beginning of the discipline, there continues to be confusion and lack of standardisation regarding terminology in this aspect.
In this paper, we try to contribute to new insights in this research by means of selecting examples from an extensive experimental programme involving different raw materials: from rock crystal (the purest form of quartz found in nature) to vein quartz and quartzite, with the latter two materials extensively used for knapping throughout Prehistory and still poorly understood in terms of microwear. For data recording, we preferentially used sequential experiments and resorted to both Optical Light and Scanning Electron Microscopy.
We focused our interest on describing the main groups of wear features. The results obtained allowed us to assess the different mechanical behaviours under the stressors induced by tool-use from a group of raw materials with the same chemical composition but very different in structure. Furthermore, we propose the revision of some terms commonly employed when documenting micro-wear on quartz and similar rocks, as well as recurring concepts coming from materials and geological sciences (e.g. tribology, quartz exoscopy...).
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