1The Carrer Paris hypogeum is located in Cerdanyola del Vallés (Vallès Occidental, Barcelona, Spain) (Figure 1).
Figure 1: A) Individual 5 during the excavation process in Carrer Paris Chalcolithic hypogeum. B) Detail of the cranium and the mandible of Individual 5 with red pigments remains “in situ”. C) Geographical situation of Carrer Paris site (Cerdanyola del Vallès, Barcelona).
Figure 1 : A) Individu 5 durant la fouille de l’hypogée Chalcolithique du Carrer Paris. B) Détails du crâne et de la mandibule de l’individu 5 avec les pigments rouges pendant l’excavation. C) Situation géographique de Carrer Paris (Cerdanyola del Vallès, Barcelone).
2The site was discovered accidentally during the foundation works of new housings constructions. It is a funerary structure with oval plant. The north part of the site was destructed by the constructing works but the south side kept preserved. During the excavation processes were identified different levels of burials. In the second burial level we located four individuals, three of them in a primary position and the fourth displaced and lying close to the west wall of the structure (Francés Farré et al., 2004; Gibaja et al., 2006). One of these primary burials belongs to individual 5 which has been restored and has been sampled for this study.
3Individual 5 is an adult skeleton buried in lateral decubitus position. The longitudinal axis of the body was oriented north-south with the crania looking to the east. During the excavation we identified red pigment remains over its mandible, in the soil of the burial level II and inside of the ceramic glass found together with the skeleton, possibly as a funerary present (Figure 1).
4The skull was extracted in block with sediment and it was transported to the Restoration Laboratory in IPHES. The conservation procedures involved the cleaning and reconstruction to achieve the anthropological study, to observe the pigments distribution and to analyze the composition. The chemical analyses of the colouring materials were performed with non-destructive methods to guarantee the complete preservation of the pigments.
5We documented the state conservation of the bone using high resolution photographies. We also conducted an observation study using a binocular microscope to distinguish more signs of colouring material. We took control samples of the sediment to test if the red material was present on the sediments.
6We analyzed the pigments on the left mandibular fragments from individual 5, four samples of the sediment recovered during the cleaning of the cranium and one mineral standard sample of cinnabar from Almadén mines (Spain) to compare with the archaeological samples.
7The analyses on the mandibular fragments (CP1 and CP2) were done before the restoration processes with environmental scanning electron microscope (ESEM) and X-ray microdiffraction (µ-DRX). We present the analyzed areas in Figure 2.
Figure 2: A) Left side of Individual 5 mandible before the conservation treatments. B) Detail of the red pigment concentred in fragments CP1 and CP2 and areas analyzed by ESEM-EDS and X-ray diffraction.
Figure 2 : A) Coté gauche de la mandibule de l’individu 5 avant les traitements de restauration et détail du pigment rouge concentré sur les fragments CP1 et CP2. B) Zones analysées par ESEM-EDS et micro-diffraction de rayons X (µ-DRX).
8The Environmental Scanning Electron Microscope used was FEI Quanta 600 (ESEM) with an attached X-ray Energy Dispersive Spectroscopy (EDS) of Oxford Instruments. The samples were evaluated under 0,68 Torrs of chamber pressure, 20kV of beam energy and 10 mm of working distance. We used simultaneously detectors of the secondary electrons (SE) and the backscattered electrons (BSE). We documented the distribution of the pigments and sediment presents over the surface of the mandible and we analyzed the elemental composition of pigments.
9Microdiffraction (µ-DRX) measurements were made using a Bruker-AXS D8-Discover diffractometer equipped with parallel incident beam (Göbel mirror), vertical q-q goniometer, Cuka radiation, XYZ motorized stage and with a GADDS (General Area Diffraction System). The samples were placed directly on the sample holder and the area of interest was selected with the aid of a video-laser focusing system. An X-ray collimator system allows us to analyze elliptic areas of 500 x (500/sinq1) microns. We collected frames (2D XRD patterns) covering 15-70º 2q from three different detector positions (q1: 16.27, 25.25 and 34.2º) at a distance of 15cm from the sample. The exposition time was 120s per frame and it was chi-integrated to generate the conventional 2q vs. intensity diffractogram.
10The identification of the minerals was achieved by comparison of the XRD diffractogram with the ICDD data base (release 2007) using Diffracplus Evaluation software (Bruker, 2007).
11Once we known the nature of pigments (and their implication for the archaeological study) and sediment, we proceeded to planning a methodology of conservation. We documented that the cranium has diagenetic modifications due to the sediment pressure and humidity: deformations of the bone, crushing, distortions, displacements, fissures and cracks filled by sediment. The facial region has important missing parts and some teeth have been lost. The cranium was very broken, it has modern fractures, cracks and some parts of the bone have cohesion problems due to the vibrations from the transport and possibly by the action of plant roots. The mandible was fragmented in five pieces and one isolated teeth. All the fractures were old and only one showed a recent breakage. The fragments preserved some sediment adhered to the surface but we could observe abundant patches of red colouring material.
12We performed some cleaning tests in localized areas to determine which cleaning system was the most adequate. The removal of the sediment was done with deionized water, paintbrushes, cotton swabs and wood-sticks. The areas with pigment were cleaned under a stereo microscope Zeiss Stemi 2000C using magnification between 6.5 and 50x. Occasionally, in the regions without cohesion or broken we used the acrylic resin Paraloid B72 dissolved with acetone at 5-10% to consolidate and 20% to glue. This synthetic resin is well-known in conservation and is the most recommended to preserving bones. It has showed the best long-term stability in test but at the same time it was demonstrated that it is not completely reversible (Johnson, 1994; Shelton & Chaney, 1994; Johnson, 2001), so we only used it when it was completely necessary for the bone preservation and we didn’t used it directly over the pigments.
13The ESEM observation allows us to document the distribution of the pigments between the bone surface and the sediment from the site (Figure 3). The elemental microanalysis (EDS) in the different analysis points permit us to identify that the red pigment is composed mainly by minerals with the elements S and Hg in association. These results allowed us to characterize that the base of red pigment is cinnabar (HgS). The size and shape of cinnabar crystals are described Figure 3.
Figure 3: ESEM-EDS and X-ray diffraction results of sample CP2-P1.
Figure 3 : Résultats des analyses avec ESEM-EDS et de la micro-diffraction de rayons X obtenus pour l’échantillon CP2-P1.
A) ESEM-EDS analysis: location of pigments between the bone and site sediment with BSE detector. B) Detail of cinnabar crystals (BSE) in the same site of interest. As shown in the image, the cinnabar crystals present a maximum size of 15 µm and are defined as equidimensional or elongated with subhedral forms. Their roundness is subangular and the habits are tabular (Bullock et al., 1985). C) Elemental spectrum of the biggest cinnabar crystal shown in image B. The elements Hg and S of the cinnabar (HgS) are associated to O, Al, Si, K and Ca. D) X-ray diffractogram and site of interest. The most abundant compounds detected are cinnabar, calcite, quartz and fluorapatite.
A) Analyses ESEM-EDS: situation des pigments entre l’os et le sédiment avec detector BSE. B) Détail des cristaux de cinabre (BSE) au même endroit. Les cristaux de cinabre montrés sur cette figure présentent une taille maximale de 5 µm et sont décrits comme équidimensionels ou allongés avec une forme subhédrale. Leur rondeur est subangulaire et leurs habitudes sont tabulaires (Bullock et al., 1985). C) Spectre élémentaire du plus grand cristal de cinabre de l’image B. Les éléments Hg et S du cinabre (HgS) sont associées aux éléments O, Al, Si, K and Ca. D) Diffractogramme de rayons X et lieu d’intérêt. Les composés les plus abondants détectés sont du cinnabre, de la calcite, du quartz et de la fluorapatite.
14We have detected other elements associated oxygen (O), aluminium (Al), silicon (Si), calcium (Ca) and depending the areas magnesium traces (Mg), potassium (K) and iron (Fe). These elements are related possibility to calcite, quartz and aluminiumsilicates.
15Using the µ-DRX we can confirm that the composition of the coloring materials of the mandible is composed principally by cinnabar (HgS) and quartz (SiO2). We also detected the bone fluorapatite (Ca5 (PO4)3F) and the calcite (CaCO3) of the sediment (Figure 3). As the archaeological samples, the geological cinnabar sample is composed mainly by cinnabar and quartz (Figure 4).
Figure 4: Comparison of the X-ray diffractogrammes of CP1-P1 and the geological reference of Almadén cinnabar. Both samples present cinnabar and quartz as principal components.
Figure 4 : Comparaison des diffractogrammes de rayons X de CP1-P1 et de l’étalon géologique du cinabre d’Almadén (Spain).
16We have not located cinnabar on the sediment samples and all of them are composed by calcite, dolomite, quartz, muscovite and chlorite. We present the all results of the X-ray diffraction on Table I.
Table I: X-ray diffraction results in pigment, bone and sediment from Carrer Paris Individual 5.
Tableau1 : Résultats de diffraction de rayons X obtenus sur le pigment, l’os et le sédiment de l’individu 5 de Carrer Paris.
17During the conservation processes we did not find colouring material in other regions of the cranium bones. Once restored the mandible, it was possible to manipulate it to study and describe the pigment distribution. The colouring material is concentrated on the left mandibular body. There are some red pigments inside the teeth alveolus and some very small remnants of pigment in the internal side of the mandible and in the right side (Figure 5).
Figure 5: Mandible after the conservation treatments. A) General view of the piece. B) Detail of the pigment distribution concentrated on the left side.
Figure 5 : Mandibule après les traitements de restauration. A) Vue générale de la pièce. B) Détail de la distribution des pigments concentrés sur le coté gauche.
18In Iberian Peninsula the use of Ferric oxide as red coloring material has been documented in funerary ritual since the Paleolithic period (Duarte, 2002). The early use of cinnabar for funerary rituals dates from the Middle Neolithic in Gavà mines (Barcelona, Spain) (Gómez-Merino & Gispert-Guirado, 2010). The cinnabar has been used frequently in funerary rituals during Bronze Age and it has been documented in several sites, where it has been documented the use of cinnabar to paint the funerary structures and human skeletons (Martín Gil et al., 1995; Delibes de Castro, 2000). The use of cinnabar during the Calcolithic in north-east of Iberian Peninsula is not well documented. The most important mines of this mineral are located far away in other regions (Casanova & Canseco, 2002; Calvo, 2008). The identification of cinnabar in Carrer Paris hypogeum is interesting because it indicates a selection or preference in using this coloring material, which is not abundant in the territory. The closest mines are Garralda (Navarra), Albarracín (Teruel) and Espadán (Castelló) which are located between 280 km and 320 km in NW, W and SW direction, respectively (Delibes de Castro, 2000). Thus, this mineral must be obtained by travelling long distances or by exchange with other groups. We have analyzed a sample of Almadén cinnabar to compare with our archaeological samples, but it does not mean that Almadén was the origin for the cinnabar of Carrer Paris site. To determine the origin of this raw material, we require further studies and a systematic analysis of all possible sources. The cinnabar is a poisonous substance and in low concentration has sedative properties. Martín Gil et al. (1995) and Delibes de Castro (2000) had suggested that cinnabar was used in Bronze Age in funerary ritual to preserve the bodies. Currently, cinnabar has been used in traditional medicine and as cosmetic in China (Chuu et al., 2007; Huang et al., 2007) and in the Arabic Peninsula (Hardy et al., 1995). We think that the cinnabar identified in the mandibular symphysis of the individual 5 seems to be linked to the funerary context but we cannot rule out other possibilities.
19We thank Marc Guardia and Òscar Sala their collaboration in field work and sampling. Judit Vidal, Anna Rufà, Clara Gené and Marina Lozano their help during the conservation treatments. Gerard Campeny and Jordi Mestre for the photographic support. Florent Rivals and Hugues-Alexandre Blain their suggestions with the French, Mercé Moncusí her technical support in the ESEM analysis and María Soto her help with the mineralogical descriptions. We want to thank the ArboCo 2010 organizers for their invitation to the publication of this manuscript and the comments of two anonymous referees that improved the text. This paper is part of project SGR2009-813.