Refitting flakes to cores is a well-developed way to investigate how stone tools were made. Here the author takes on the formidable task of refitting the stone blocks of menhirs, orthostats and megalithic tombs to their quarries. The results are impressive: the order of erection in a row of menhirs, the method of construction in a passage grave and the monumental chronology of a region are just three of the rewards of this promising new method.

International audienceRemains 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 some 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

Abstract

Installées sur la partie haute d’un versant exposé au sud-est, en bordure d’un thalweg peu imprimé, trois grandes structures de combustion en fosse et une carrière d’extraction de blocs de granodiorite ont été fouillées en extrême urgence sur la commune de Mazières-en-Mauges, à cinq kilomètres à l’est du centre de Cholet (Maine-et-Loire). Elles témoignent d’une chaîne fonctionnelle requérant un gros investissement de travail pour un usage exceptionnel, sans abandon de mobilier. Les structures de combustion sont datées par le radiocarbone autour de 5800 BP, soit l’intervalle 4700-4600 avant notre ère après calibration. Cela correspond à la fin du Néolithique ancien et au début du Néolithique moyen dans la région. L’analyse anthracologique montre l’usage quasi exclusif de chênes de gros calibre, probablement récoltés sous forme de bois vert. De telles structures sont connues dans cet intervalle chronologique sur le territoire français, mais c’est la première fois que l’on peut documenter la phase de construction préalable à leur fonctionnement.

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