Fission track dating and provenience of archaeological obsidian artefacts in Colombia and Ecuador

International audienceWe dated by the fission track method eighteen samples of obsidian glass. Of these, seventeen were artefacts collected in prehispanic archaeological sites from Ecuador and Colombia and one comes from a secondary obsidian source located in southern Colombia. When our data are compared to (i) the fission track ages of obsidian from volcanic sources and (ii) the PIXE chemical composition of the same artefacts and of samples from obsidian sources, eight discrete age/composition groups appear.Fifteen artefacts might come from a single unknown source: three others from sources in the Sierra de Guamani (East of Quito): one from the Mullumica rhyolitic flow and two from the Quiscatola/Yanaurcu sources. A fourth artefact migh come from the South Colombia source of Rio Hondo. At least five other sources are necessary to account for thr variety of ages and compositions found in the arefact collection studied