A PIXE/Fission-Track Dating Approach to Sourcing Studies of Obsidian Artefacts in Colombia and Ecuador

What is it about?

Using PIXE, we measured the chemical composition of 142 obsidian artefacts from 45 prehispanic archaeological sites and 22 obsidian samples from seven geological occurrences from Colombia and Ecuador. From PIXE data, these 164 samples may be classified into five chemical groups. Two source samples and a selection of 41 artefacts were dated by fission tracks. Some artefacts belonging to a single chemical group may have different formation ages and, hence, come from different sources. This results, for these 41 artefacts, in a minimum of eight sources, of which only three are identified. These are the Rı́o Hondo (Colombia), Mullumica and Quiscatola-Yanaurcu (Ecuador) sources. More than half (22) of the artefacts dated by fission tracks pertain to a single 0·25–0·30 Ma, age/composition group related to an unknown source. These artefacts were found essentially in archaeological sites (four in Colombia, 12 in Ecuador) of the Regional Development Period situated along the Pacific coast.

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