Archaeologists in America have used neutron activation analysis (NAA) to establish the origins of Olmec pottery found across Mesoamerica.
    Jeffrey Blomster of George Washington University, Hector Neff of Cal State-Long Beach, and Michael D. Glasock of University of Missouri used the technique in a project to determine if Olmec-style pottery all came from the same area, from several areas equally, or some combination of the two.
    In order to complete their investigation, which was reported in the journal Science, they needed a large number of samples from many sites, which were provided by the cooperation of colleagues at the Instituto Nacional de Antropología e Historia, Mexico's federal archaeological agency, and the Universidad Nacional Autónoma de México, who between them contributed over 1000 ceramic artefacts, which were compared with 275 samples from clay sources throughout the region.
    The results were conclusive, showing that white-ware and vessels with Olmec-style designs made at San Lorenzo and other large Gulf Coast centres is found throughout Mesoamerica, and that nobody at non-Olmec centers was exporting their Olmec-style pottery.
    For example, at Etlatongo in the mountains northwest of the Oaxaca Valley, pottery was received from Olmec centres and copied by local Mixtec potters, but copies of Olmec-style ceramics made in the nearby Oaxaca Valley weren't brought in, suggesting that the Olmec packaged and exported their beliefs in specialized ceramic designs throughout the region, which quickly became hallmarks of elite status in various regions of ancient Mexico.
    Blomster said "Many of us - myself included - just accepted without the kind of robust data we should have had that places like Oaxaca exported their versions of the Olmec style to other parts of Mesoamerica. And of course, our research debunks that. Perhaps if we sampled thousands more sherds from San Lorenzo, we would find a pot that came from outside the Gulf Coast, but it would be fairly insignificant in light of the pattern we report in our Science article"
     He added "We have to acknowledge that the exporters (the Olmec) and the receivers may have had very different interests in the system. I think we have to move beyond a purely economic model; for the Olmec, this involved more than simply acquiring raw materials from other regions in Mesoamerica. The fact that it involves ceramic vessels which display iconography, representing an underlying ideology and religion synthesized by the  Gulf Coast Olmec, suggests that something much deeper is at stake than  simply maintaining exchange relationships."
    "We know that throughout Mesoamerica, the Olmec interacted with groups who had already achieved some kind of socio-political complexity. These groups, such as those in Oaxaca, were probably already at the chiefdom level. We believe while the Olmec were more socio-politically complex - as the Red Palace discovered by Ann Cyphers at San Lorenzo indicates - we simply cannot say they somehow created these cultures. Impact, yes; created, no."

Source: Archaeology (28 March 2005)