Friday, October 28, 2005

New Digs Decoding Mexico's "Pyramids of Fire"

New Digs Decoding Mexico's "Pyramids of Fire": "The largest unanswered questions about Teotihuacan concern its demise. Why, for example, was the city largely abandoned around A.D. 650?

The recent excavations are revealing new bits of information that help piece together an answer.

Spence has found evidence that the health of Teotihuacán's population declined in the city's final century. Residents' teeth have tell-tale lines that form in childhood during episodes of severe stress, such as malnutrition or infection.

"Basically growth stops as the body concentrates on survival and repair," he said. "Then as the stress passes, the growth continues again. But there's a line left in the tooth that represents the stress episode."

Because teeth only grow during childhood, scientists can put a general age to when the stress happened. These signatures of bodily stress remain in adult teeth.

"We have shown that in the last century of the city there is a growing problem of some sort. We get more and more indications showing up in adult teeth," he said.

'We don't know exactly what happened at the final stage, but we know certainly the city was destroyed by man, not by natural disaster,' Sugiyama said.

Researchers are uncertain whether insiders or outsiders caused the destruction, Sugiyama said, but they do know that the instrument was fire, particularly on Teotihuac?n's monuments.

The archaeologist says an invading army could have set fires to the monuments as a signature of their conquest.

Spence, however, says the evidence suggests to him the fires were set during an internal revolt.

According to his theory, the deteriorating health of the city's poor was likely exacerbated by a drought or a disruption to the food supply. This spurred a revolution against the ruling elite and their symbols of power?temples, pyramids, and palaces.

'The destruction seems to have skipped the vast majority of the city and focused on the elite and punished the elite. That suggests a revolt to me,' he said."