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Le verre à l’Age du Fer

Les Celtes en Europe


Dernière modification : 6 septembre 2017

Katherine GRUEL & Nathalie VENCLOVÁ

 

Dans le cadre du Groupe de recherche européen du CNRS (GDRE) sur les Celtes en Europe, une réflexion a été initiée sur l’artisanat du verre, son évolution, les nouvelles pistes de recherches qui s’ouvrent dans ce domaine. Le verre reste un marqueur typo-chronologique important pour cette période. Nous avons donc sollicité les principaux spécialistes de la question pour un rapide bilan des questions sur lesquelles ils travaillent, associant les points de vue typologique, technotypologique et physico-chimique.

 1- Celtic glass, which questions ?

Par Ruppert GEBHARD, Archäologische Staatssammlung, Munich, Germany.
The beginning of the glass production in Europe is linked to the distribution of bronze production and working. The production of glass beads starts in the early 2nd millennium B.C., an extensive production, however could not be observed before the late Bronze Age (About 1000 B.C.). The early European glass production could not be allocated to certain centres, but it is agreed, that it has been developed at different sites independently from the glass production in the Near East. That means that they are Importing raw material and they are in contact to the Hellenistic Mediterranean. Only few core areas of production are existing
Details of the productions processes can be reconstructed : periods of innovation and tradition, Changes of the composition (raw material and colouring agents)
Some questions are still to be solved :

  • How can a production centre be characterized ?
  • Which Source of the raw material ?
  • Who coloured the glass ?

 2- Verres de l’Age du Fer retrouvés en Europe.

Par Bernard GRATUZE, Institut de Recherche sur les Archéomatériaux, UMR 5060 du CNRS, Université de Bordeaux 3, Université d’ Orléans.
Quatre grands groupes identifiés au sein des verres de l’Age du Fer retrouvés en Europe :

  • Verres bleus au cobalt à fortes teneurs en alumine et magnésie (cobalt originaire des gisements d’aluns) (1er Age du Fer)
  • Verres noirs à fortes teneurs en fer (1er Age du Fer) (quartz + natron + scories / quartz + sels de fer proches des aluns ?)
  • Verres à faibles teneurs en alumine et en potasse (1er / 2nd Age du Fer) (quartz + natron ?)
    Verres bleus au cobalt
    Verres bleus au cuivre (certains à fortes teneurs en Cu)
    Verres de teinte ambré
    Verres incolores (antimoine et/ou manganèse) : Production précoce de verres décolorés au manganèse entre le 8e et le 5e siècle.
  • Verre au natron de composition classique : syro-palestinienne (1er et 2nd Age du Fer)

 3- Le verre en contexte archéologique

3.1- Celtic glass from Manching and La Tène Europe

Par Rupert GEBHARD, Archäologische Staatssammlung, Munich, Germany.
The beginning of the glass production in Europe is linked to the distribution of bronze production and working. The production of glass beads starts in the early 2nd millennium BC. Extensive production, however, cannot be observed before the late Bronze Age (about 1000 BC). During the period from the 7 to the 5th century BC (late ‘Hallstatt’ period) bead production developed to a significant level in the upper Adriatic region. The focus of this paper is the Hellenistic period, when a sudden rise of glasswork in the industrial centres of the Central Europe can be observed. The Celts formed a strong commercial after a migration period from the 4th to the 3rd century BC. It was based on a network of cities (‘Oppida’). They were the centres of the Celtic tribes, places where there was extensive production and development of different crafts. This structure facilitated a new boom of glassworking in selected sites. The contribution focuses on this main period of Celtic glass production and discusses inter alia the following topics : raw material, colour and shape, production and distribution areas, innovation and tradition in glassworking. Results obtained in an analysis 25 years ago from the Celtic oppidum of Manching are compared to recent investigations from other sites.

3.2 Le verre rouge celtique

Par Virginie DEFENTE, Université Rennes 2 Haute Bretagne, France.

Dès la fin du Ve siècle av. J.-C., un verre rouge dit « celtique » est utilisé pour décorer des bijoux (fibules, torques, bracelets), plus rarement des armes ou des éléments de char, que l’on trouve principalement dans des tombes de la haute et la moyenne vallée du Rhin. Ce verre, de type silico-sodo-calcique, doit sa couleur rouge au cuivre (5-10 %) et au plomb (20-50 %). A partir des analyses physico-chimiques des verres rouges celtiques tant continentaux qu’insulaires, on peut reconsidérer les différentes interprétations déjà proposées et de les discuter. Par ailleurs, l’utilisation comme la fabrication du verre rouge celtique relèvent-elles d’ateliers locaux travaillant pour une clientèle locale ou doit-on envisager d’autres modes de fonctionnement ?

3.3 les premiers objets de parure en faïence et en verre du massif armoricain

Par Bernard GRATUZE, Institut de Recherche sur les Archéomatériaux, UMR 5060 du CNRS, Université de Bordeaux 3, Université d’ Orléans & Anne-Françoise Cherel, INRAP, France.

Un inventaire des objets de parure protohistoriques en verre et en faïence découverts en Bretagne est encours. Cette démarche originale vise à dresser un bilan des données disponibles en les réactualisant, en complément des travaux de J. Briard initiés en 1984 sur l’âge du Bronze. Par ailleurs, aucune étude synthétique sur la parure en verre de l’âge du Fer en Bretagne n’a été menée. Les découvertes très ponctuelles d’éléments de parure en verre en contexte funéraire, plus rarement dans les habitats, alimentent pourtant un corpus de plus de 180 objets. L’étude de leur contexte de provenance, en corrélation avec les analyses typologiques et chimiques, apportent des informations parfois inédites. Notre étude s’inscrit dans le cadre de la réalisation d’un corpus des découvertes de perles et pendeloques en verre et faïence au niveau national, pour une période qui s’étale du Chalcolithique à l’âge du Fer. Plus de six cents objets, représentant près de cent cinquante sites couvrant cette période et englobant l’ensemble du territoire français, ont déjà été recensés et analysés. Les éléments de parure en verre et en faïence retrouvés en Bretagne sont replacés au sein du modèle chimico-typo-chronologique développé à partir des relations observées entre la composition, la chronologie et la provenance de l’ensemble de perles en verre étudiées à ce jour. Les résultats préliminaires de ce travail ont déjà fait l’objet d’une communication au sein du colloque de l’AFAV de Rennes (11/2007) et seront prochainement publiés.

3.4 Iron Age glass collection from Němčice and its chemical and technological characteristics

Par Natalie VENCLOVÁ, Institute of Archaeology, Academy of Sciences, Prague, Czech Republic & Václav HULÍNSKÝ, Department of Glass and Ceramics, Institute of Chemical Technology, Prague, Czech Republic.
The Iron Age settlement of Němčice in Moravia (Czech Republic) provided evidence of local glass-working in the 3rd-2nd cent. B.C., the earliest so far identified in La Tène Europe. The workshop produced artefacts usually classified as „Celtic glass“. The assemblage of over 2,000 objects includes not only hundreds of finished products such as glass bracelets, finger rings, spacers and beads, but also a considerable quantity of glass-working waste, semi-products and raw glass. A series of glass samples from Němčice, from sites in The Netherlands and from the Sanguinares shipwreck, from the time span of 6th-1st cent. B.C., were submitted to SEM-EDS, NAA and XRF analyses. Their results confirmed the similar chemical composition of the raw glass – appartently imported natron glass -, glass-working component and finished products from the site to that of the other La Tène glass assemblages. Comparison of chemical and archaeological data points to the significance and limits of the applied analytical methods for different aspects of pre-Roman glass research.

 3.5 La Tène glass from Poland and eastern Austria, a review of key topics

Par Maciej KARWORWSK, Institute of Archaeology, University of Rzeszów, Poland.
An accurate inventory of La Tène glass jewellery from Poland and eastern Austria has shown that these artefacts are the most numerous non-ceramic category of archaeological finds on Celtic settlements in middle and late La Tène periods. At the same time they are one of the most numerous imports from La Tène Culture to Przeworsk and Oksywie Cultures in Poland. Glass finds, mainly bracelets, turned out to be not only very good chronological determinants but also important indicators of broad changes in central-eastern Europe in the second half of 3rd century BC. Some of the glass ornaments also display local – eastern La Tène – stylistic features. Research on the chemical composition of these glass artefacts showed an interesting relationship between chronology and concentration of some elements in the basic composition of the glass.

 4- Données physico-chimiques

4.1- Early Iron Age glass from Italy : Archaeometric characterization and comparison with the Final Bronze Age production

Par Ivana ANGELINI, Dipartimento di Geoscienze, Università degli Studi di Padova, Italy.
Italian vitreous materials of the Bronze Age (faience, glassy faience and glass) show a large variation in chemical composition and texture. Recent research -clearly identified the strong relationships existing between these variations and the age and/or the geographic origin of the materials. A short review of the different Bronze Age glass production and exchanges will be presented, with a special focus on the Final Bronze Age production. Actually the only secure evidence of the typical European LMHK (Low Magnesium High Potassium) glass production was found in North-East Italy, specifically in the Final Bronze Age site of Frattesina, in the nearby and coeval site of Mariconda di Melara and, possibly, in a new settlement near Verona now under excavation. Three research projects aim to investigate the possible continuity in glass production through the beginning of the Iron Age, and to understand the chemical variations of the glass objects during this Age. The first research is focused on the archaeometric investigation of glass beads belonging to the Golasecca culture (Lombardia), dated from the IX to the VI cent. B.C. The second study concerns glass beads of the Villanovian culture phases I-III (IX-VII cent. B.C.) from the Bologna area, and the third research is focused on Sardinian vitreous materials dated from the Middle Bronze age to the First iron Age. The samples are routinely analysed by SEM-EDS (Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy), EPMA (Electron Probe Micro Analysis), XRD (X-ray Diffraction) and DIP (Digital Image Processing), whereas others techniques have been used only for specific questions, such as the identification of peculiar colouring agents. The results of the analyses will be presented and discussed pointing out the specific information obtained by each analytical technique. The data are analysed as a function of the age, the provenance and, if relevant, the specific typologies of the beads

4.2 Polychrome Mediterranean vessels and beads : exchanges in western Mediterraneran area during Iron Age

Par Rossella ARLETTI, Dipartimento di Scienze della Terra, Università di Modena e Reggio Emilia, Italy.
In this work a large group of transparent and opaque glass artefacts, dated from the 7th to the 3rd century B.C., are analyzed. The items came from archaeological sites of Etruscan contexts in Northen Italy (Spina and Bologna) and from Mozia Island (Sicily), where the co-presence of greek and punic culture is attested. Highly decorated beads and vessels of the Mediterranean first and second groups were characterized in order to : i) provide new quantitative chemical data of Iron Age glass ; ii) single out possible differences among finds recovered in sites belonging to different cultural contexts, and between vessels and beads, in order to understand whether different manufactures were present at the same time. The chemical analyses of major and minor elements were performed by electron microprobe (EMPA). The nature of the opacifying and colouring agents was determined by X-ray powder diffraction. Since only micro volumes were sampled from the artefacts, the diffraction experiments were successfully carried out with an original method based on the use of a single crystal diffractometer equipped with a CCD camera. Most of the samples are characterized by low and quite constant levels of MgO and K2O and can be classified as Low Magnesium Glass, produced with a mineral source of alkalis. On the contrary, CaO and Al2O3 show a wide range of variability. Yellow opaque decorations are rich in lead antimonates, while calcium antimoniates are present in white and light blue ones. MnO was detected only in the violet artifacts. Cobalt and copper are the responsible for the green and deep blue colorations, respectively. The homogeneity of the chemical data allows to hypothesize a common origin for beads and vessels recovered in different cultural contexts.

4.3 Etruscan glasses from northern Italy : new chemical data

Par Julian HENDERSON, Department of Archaeology, University of Nottingham, United Kingdom.
A large sample set of transparent and opaque glass artefacts recovered from Etruscan contexts in northern Italy (Bologna and Spina (FE) necropoleis) and dated to a period between the 6th and 4th century BC have been analysed. Samples of highly decorated beads, spindle whorls and vessels of the ‘Mediterranean Group I’ (Alabastron, Oinochoes, Amphoriskos) were selected in order to determine whether these different glass artefacts were produced at the same manufacturing site. While the vessels almost certainly originate from Greece, the beads could derive from a more ancient local production ascertained at the site of Frattesina (Rovigo, Italy) and dated to the Bronze Age.

 

The aims of this study are : (i) to characterise a set of Iron Age glass artefacts, thus providing new quantitative chemical data ; and (ii) to identify possible differences between finds recovered from different localities and between glass vessels and beads, in order to establish whether different manufactures were active contemporaneously.

 

The chemical analyses of major and minor elements were performed with an electron microprobe. The nature of the opacifying and colouring agents was determined by X-ray diffraction. The sample set is relatively homogeneous and most of the samples can be classified as low magnesium glass. The yellow opaque decorations are rich in Pb and Sb, while only Sb is present in the white and light blue samples. The XRD analyses confirmed the presence of lead antimonates in the yellow decorations and of calcium antimonates in the white and light blue decorations

4.4 Parures protohistoriques en verre du site de Lacoste (Mouliets et Villemartin, Gironde, France). Récentes approches technologiques vues par microscopie électronique

Par Cédric GÉRARDIN, Stéphan DUBERNET, Michel PERNOT, IRAMAT-CRP2A, UMR 5060 CNRS - Université de Bordeaux & Christophe SIREIX, INRAP, France.
L’observation visuelle fine à différentes échelles des perles et bracelets celtiques en verre constitue une base essentielle à l’établissement d’hypothèses sur les chaines opératoires. Elle permet d’isoler des critères morphologiques dans un premier temps et de juger en suivant de leur pertinence dans le cadre des recherches sur les techniques de production. Les récentes études tracéologiques menées en microscopie électronique à balayage (SEM) sous vide partiel, révèlent des traitements mécaniques singuliers sur les surfaces de certains types de parures, tels que l’accentuation des contrastes entre teintes, l’opposition de rugosité. A ce stade, il est difficile de les interpréter avec certitude. Sont-ils dus à une volonté des artisans de créer des effets esthétiques, ou découlent-ils de gestes techniques inhérents à une mise en forme de ces parures ? A titre d’exemples, nous détaillerons le cas des bracelets à décor bourgeonnant et les perles à bossettes et décor spiralé du site de Lacoste.