Variscita y ámbar en el neolítico gallego. Análisis arqueométrico del collar del túmulo 1 de chousa nova, silleda (pontevedra, España)

Abstract

The excavation of barrow 1 of Chousa Nova, Silleda, Pontevedra (NW Spain) offered surprising results. This mound, in spite of experiencing a large number and types of anthropic damage, still preserved a great constructive complexity. Within its megalithic chamber, formed by 5 granite orthostats and a large roofing slab of, also in granite, a set of archaeological materials appeared. These were an axe, a chisel and a polishing stone, with a set of 35 beads, most of them of a green stone and the rest of an organic material, with an extremely high degree of alteration, inserted between them. The analytical techniques have been in all cases not-destructives (X-ray diffraction and fluorescence spectroscopy, infrared spectroscopy, optical microscopy and environmental electronic microscopy, with microanalysis). The archaeometric analysis results show a mineralogical nature of these materials, based in variscite and amber. The textural and compositional features are very homogeneous between each assemblage of beads. The importance of the alteration phenomena and dissolution of the archaeological objects are determined and quantified. This alteration is due to an intense chemical attack during the burial periods. The possible source areas of provenance for these materials are also discussed on the basis of geochemical data obtained in the analysis.