PARTICLE-INDUCED X-RAY EMISSION (PIXE) ANALYSIS OF OBSIDIAN FROM TEOTIHUACAN*

SUMMARY AND CONCLUSIONS The main goal of this study was to perform a non-destructive provenance analysis of 50archaeological samples. PIXE analysis was performed at two accelerator-based facilities, locatedinParisandMexico,todeterminetheprovenanceoftheobsidianusedtomanufacturetheartefactsused in an early Teotihuacan period. These analyses helped to ascertain which regions were incontact during this period.Among the samples studied, 43 could be assigned without ambiguity tothetwosourceswellknowntohavebeenusedbytheTeotihuacanstate,namelyOtumbaandSierrade Pachuca, plus two other sources, Paredon and Zacualtipan. These results agree with thesuggestion that Otumba and Sierra de Pachuca were the main sources controlled by the people ofTeotihuacan and that they had brought raw materials and devices manufactured in the Sierra dePachuca workshops to the city and the Central Plateau. The higher dispersion of the group fromSierra de Pachuca may also indicate that different sources from this area could have been used.Cobean (2002) found three sources, S. Pachuca I, II and III, although all samples from Sierra dePachuca analysed in this study belong to S. Pachuca I. The people of Teotihuacan took advantageofthegoodqualityofgreenobsidian,intensifyingitsexploitationandexpandingitsdistributiontoanumberofsitesinMesoamericawithaconsequentimprovementintheireconomy(Spence1981).This result is supports the fact that most of the obsidian artefacts found were made using obsidianfromthesourcescontrolledbyTeotihuacans(OtumbaandSierradePachuca).However,theresultsalso indicate that some obsidian was obtained from commercial exchange. The presence ofobsidian from Paredon (Puebla), on the way to Veracruz, might suggest early relationships withother communities on the Central Plateau, and an exchange of resources among these regions tofulfil the demand from an increasing Teotihuacan population; or perhaps the control of othersources, like Zacualtipan and Paredon, by Teotihuacans. Further work is in progress to analyse an