GOUEZIN Philippe

Abstract:

À la suite des travaux de P.-R. Giot, réalisés à partir du milieu des années 1950, le tumulus sud de Barnenez, situé sur la côte nord du Finistère, est l’un des plus emblématiques parmi les mégalithes bretons. Depuis lors, les connaissances concernant ce monument de soixante-dix mètres de long n’avaient guère été renouvelées, si ce n’est par la publication de la monographie correspondant à ces travaux, à la fin des années 1980. Trente ans plus tard, ce fut notamment l’objet d’un programme de recherche international et d’une thèse en cours à l’université de Rennes 1. Il mêle l’étude de l’ornementation des espaces internes et celle de l’architecture. Parmi les résultats obtenus, la chambre H et son couloir montraient des évidences d’état antérieur à celui que l’on observe aujourd’hui. Nous avons donc décidé de réaliser un sondage pour rechercher des traces éventuelles de l’état antérieur au sol. Les résultats ont dépassé nos attentes par la bonne conservation du plan du monument précédent qui a été en grande partie volontairement démonté. Son couloir débouchait directement dans une chambre mégalithique dont certains éléments sont encore en place. L’antichambre que nous connaissons aujourd’hui pour le dolmen H n’existait pas. L’étude de la façade occidentale a également révélé une histoire architecturale complexe. Elle présente de nombreuses pierres dressées. Il s’agit d’un renfort contre la pente sur laquelle est construite la masse tumulaire. Mais, il y a également une réelle mise en scène proche de celle d’un alignement de pierres dressées à l’air libre. De plus, des rapprochements ont été faits avec le rythme des orthostates d’autres dolmens du tumulus, nous permettant de dire que les pierres dressées de la façade occidentale pourraient également provenir du démantèlement d’un autre dolmen. Réserver un tel processus aux seuls cas particuliers du remploi de fragments de grandes « stèles » brisées, initialement dressées à l’air libre, fut probablement un contresens.

The southern mound of Barnenez, situated in the northern part of Finistère, is one of the most famous Breton megaliths. It has been excavated during the 1950’s by P.-R. Giot, and the results have been published in 1987. Since then, the data about this well preserved monument haven’t been updated with the new knowledges, regarding megaliths, of the last three decades. In 2010, an international research program began on this tumulus integrating an ongoing PhD at Rennes 1 University. The first part of the study concerns the ornamentation inside the funeral spaces, with the discovery of paintings and the redefining of the engravings. The second section is an architectural study through the reading of the elevations thanks to the use of the building archaeology methodology. Both revealed multiple phases inside the tumulus, unveiling a complex history. This article will focus on two structures of the tumulus which contain discreet evidences of that substantial history, before the monument got its imposing seventy meters long final form. The first structure is the passage grave H. Two registers of ornamentation have been found revealing two distinct and successive phases inside the chamber. In the passage, the architectural study showed some ruptures in the constructional mode revealing the extensions of the passage. The passage grave H seemed to have a previous state which has been destroyed by the neolithics builders themselves. We decided to do a survey to test if the previous monument had left marks on the current passage grave’s ground. The results exceeded our expectations with a conservation of the plan and a part of the cairn with, at several places, two courses in elevation. Not all the monument has been levelled off, the orthostats of the end of the chamber are still in place. The current chamber integrated them, which explains the differences of ornamentation. The survey proves that a monument has been dismantled and some of its parts has been reused in the current dolmen H. It’s one of the first time we can prove the reuse of stones taken from a dolmen to be integrated inside another one. We needed all the elements of a megalithic architecture, marks on the ground, on the elevations and on the ornamentation, to partially understand the architectural history of the dolmen H.

The decoration of megalithic monuments is one of the
ritual actions that define the spaces that were dedicated to
the ancestors. Consideration of the artistic programmes
employed during the construction of megalithic tombs
provides parameters for analysis that support the search for the
ideology and symbolic meaning of these monuments. Most
of the known megalithic art within the Atlantic region has
already been recorded, and this has shown that carvings are the
commonest form. However, studies and analysis carried out in
the Iberian Peninsula during recent years prove that paintings
must have had a greater presence than was initially thought. By
applying methodologies similar to those developed elsewhere
in Europe, important new evidence could be recovered. In this
paper we propose a programme of research for the megalithic
monuments of Brittany.

(Journal of Raman Spectroscopy, accepted 9 nov 2015, published on line 28 dec 2015, DOI 10.1002/jrs.4852) Remains of pictorial decorations in a series of six representative megalithic monuments of Brittany (France) and two French stelae have been studied by micro-Raman spectroscopy for the first time. Fungal colonies on the painted orthostats made it difficult to obtain in situ Raman spectra of the paint components. Nevertheless, paint micro-specimens studied in the laboratory by micro-Raman spectroscopy, X-ray photoelectron spectroscopy and scanning electronic microscopy combined with energy dispersive X-ray spectroscopy have made possible to characterise the materials present. The minerals α quartz, albite, microcline, muscovite, phlogopite, celadonite, beryl and anatase have been identified in the granitic rocks supporting the paintings, while dolomite and calcite are dominant in the calcareous rocky substrata. Haematite is the main component of the red pictographs, whereas amorphous carbon and manganese oxides/oxihydroxides have been used in the black ones. Calcite, gypsum and amorphous carbon have been detected as additional components of the paint in several cases. Contamination with modern tracing materials (polystyrene and ε copper-phthalocyanine blue) has been detected in several cases. The presence of pigments as decorative elements in megalithic monuments of Western France and its possible relation with those of the Iberian Peninsula create interesting expectations for the knowledge of the European megalithic culture.