Were the Olmec builders of San Lorenzo, the first great city in ancient America, representatives of a "mother culture" that gave birth to the splendors of all subsequent pre-Columbian societies? Or were they merely one of many "sister" groups whose religion, art, architecture and social organization combined to lay, in parallel, the foundation for the advanced civilizations that later arose in the region?

These are questions that have vexed scholars for close to 50 years, sparking sometimes bitter disagreement among archaeologists and others with an interest in the origins of indigenous culture in the Americas.

"They are divided into, essentially, two camps," says Michael Glascock, professor of nuclear physics and senior research scientist at the University of Missouri Research Reactor Center. "Some of the archaeologists believe that the Olmec were influencing all the others; that because the Olmec were the primary, the largest, the most important culture, they had the greatest impact. The other philosophy is that the Olmec were just one of many cultures, and that they were all competing and they were all influencing one another."

Settling the question has proven difficult chiefly because the Olmec, unlike later civilizations in what scholars call the Mesoamerican region, left no written history. Scientists have instead had to build their cases on interpretative data drawn from analyses of artifacts unearthed by archaeological excavations. The great gulf of time separating the Olmec from our own era has further complicated matters.

"Without doubt the archaeologists who have developed these theories hold their beliefs very dearly," says Glascock. "That's where the controversy comes from, and the debate can get pretty heated. Some people, I guess I would say, are not as open-minded as they might be about this thing."

Now, thanks to a chemical analysis of Olmec pottery conducted at the University of Missouri Research Reactor Center and published in the February 18 edition of the journal Science, empirical measures are, if not opening minds, at least redefining the terms of the debate.

Earlier this year three researchers, Jeffrey Blomster of George Washington University, Hector Neff of California State University at Long Beach and MU's Glascock, for the first time conclusively pinpointed regional clay sources for hundreds of Olmec-style ceramics unearthed throughout Mesoamerica. Tying ceramic artifacts to the clay sources from which they were fashioned allowed the researchers to develop a chemical "fingerprint" for Olmec artifacts. This, in turn, made it possible to chart how the artifacts, and the influence they represented, may have spread among early population centers in Mexico and Central America.

Pinning down such patterns of exchange, the scientists say, is key to establishing whether the San Lorenzo Olmec actually attained cultural and political primacy. And establishing primacy for one location or another would settle once and for all the question of who gave birth to one of antiquity's greatest flowerings of civilization.

Published by the Office of Research.

©2006 Curators of the University of Missouri. Click here to contact the editor.