Social diversity to blame for Cahokia' collapse: Study

Challenging a popular theory that environmental causes led to the collapse of Cahokia, America's first city, archaeologists have claimed that internal conflict by social, political, ethnic, and religious factions are a more reasonable description of events that led to its demise.

Located in Collinsville, Illinois, Cahokia Mounds is the largest pre-Columbian settlement north of Mexico. It was occupied primarily during the Mississippian period (800-1400), according to the United Nations Educational, Scientific and Cultural Organisation (Unesco).

This agricultural society may have had a population of 10-20,000 at its peak between 1050 and 1150, Unesco says.

The new research suggests that Cahokia does not have a clear history of significant environmental degradation that can be linked to dissolution.

"There is no smoking gun if you want to pin Cahokia's dissolution on environmental factors," said one of the researchers Thomas Emerson from University of Illinois in the US.

Bioarchaeological evidence demonstrates that as many as one-third of the Cahokian residents were immigrants and that these immigrants likely represented groups that were culturally, ethnically, and perhaps linguistically distinct from local populations, the study said.

"Cahokia may be an interesting example of political experiment in the unification of social and ethnic diversity that failed -- probably by design," the study said.

"It makes more sense, given the heterogeneous population with differences in language, and social, religious, and political cultures to look to internal dissension at Cahokia as the underlying reason," Emerson said.

The study was published by Southern Illinois University Press.

The researchers believe that the remains of the inhabitants of Cahokia have a story to tell.

Archaeologists have been able to gather information about the lifestyle, diet, health and place of birth of those buried at Cahokia.

For the past 15 years, the archaeologists have studied curated collections from Greater Cahokia.

Evidence from osteological and isotopic analyses and radiocarbon dating was used to establish temporal and cultural context and to assess the population that once occupied the urban center of Cahokia.