Why Did Cahokia, One of North America’s Largest Pre-Hispanic Cities, Collapse? | Smart News

At the height of the turn of the first millennium, Cahokia, a city in what is now Illinois, was home to up to 20,000 people. The residents of Cahokia, who are members of the North American Mississippi culture, built huge mounds of earth that were alternatively used as homes, tombs, meeting places, and ceremonial centers. The vibrant community, according to Nathan Seppa of the Washington Post, included farmers tasked with growing corn, artisans making elaborate clay pots and sculptures, and even ancient astronomers tracking the passage of time using Stonehenge-like wooden circles .

Cahokia grew from a small settlement founded around AD 700 to a metropolis that rivaled London and Paris in 1050. But only 200 years later, the once flourishing civilization had all but disappeared and gave up its patchwork collection of monumental earthworks for reasons still unknown.

Theories about Cahokia’s death range from environmental disasters to political clashes with neighboring groups. Given the lack of concrete evidence left by the Mississippians, scientists will likely never know exactly what made them leave their homes.

Still, new research seems to rule out at least one frequently cited explanation: As Glenn Hodges reports for National Geographic, a team led by Caitlin Rankin, an archaeologist at the University of Illinois at Urbana-Champaign, found that the ground surrounds one of Cahokias Hills remained stable until the mid-19th century – centuries after the Mississippians left. The analysis, published in the journal Geoarchaeology, refutes the idea that the residents of Cahokia over-harvested wood from the surrounding forests, causing erosion and flooding that made the area uninhabitable.

Archaeologist Caitlin Rankin is excavating in Cahokia.

(Matt Gush)

“In this case, there was evidence of heavy wood use,” Rankin said in a statement. “But that doesn’t take into account the fact that people can reuse materials – like you might recycle. We should not automatically assume that deforestation has occurred or that deforestation caused this event. “

Rankin began digging in Cahokia in 2017 when she was a graduate student at Washington University in St. Louis, notes National Geographic. When examining soil samples collected near a creek at the site, she was surprised to find that there were no traces of sediment related to flooding. If the city’s ancient residents had indeed driven their ecosystem to ruin through deforestation, the swath of low-lying land in question would almost certainly have been flooded.

As Rankin reports to National Geographic, the spread of land overuse theory has been based in part on Western worldviews that link the exploitation of resources by European colonizers to Native American practices.

“It’s a western resource use mentality – squeeze everything you can,” she explains. “[But] It was not like that in these indigenous cultures. “

Scholars Neal Lopinot and William Woods of Southern Illinois University Edwardsville first proposed the land overuse theory in 1993. On the surface, the explanation makes sense: Cahokia’s infrastructure required plenty of wood, which was also used to build palisades or log walls as residential buildings and wooden circles, according to Guardian’s Lee Bey. While the Mississippians may have felled tens of thousands of trees, the soil samples that Rankin analyzed suggest that these measures were not intense enough to cause floods at the end of civilization.

Reconstructed wooden palisades in Cahokia
Reconstructed palisades or block walls at the Cahokia Mounds State Historic Site

(Joe Angeles / Washington University)

Since the residents of Cahokia did not have a written language, researchers trying to discover the metropolis’ secrets must rely mainly on archaeological evidence. Clues come in many forms – including human poop, as Lorraine Boissoneault wrote for Smithsonian Magazine in 2018.

AJ White, an archaeologist at the University of California at Berkeley, has spent the past few years studying coprostanol, a molecule produced in the intestines when food is digested, to gain insight into the population of Cahokia over time. In January last year, White and his colleagues published a study that contradicts similarly dominant narratives about the pre-Hispanic city. Far from remaining a “ghost town” in the centuries between its abandonment and modern rediscovery, Cahokia welcomed a new group of residents as early as 1500, according to Kiona N. Smith of Ars Technica.

“[W]We were able to assemble a Native American presence in the area that lasted for centuries, “White said in a 2020 statement.

Lopinot, one of the researchers who first addressed the land overuse theory, told National Geographic that he welcomed Rankin’s new take on the subject.

Finally, Lopinot adds, “Cahokia’s downfall did not happen overnight. It was a slow decline. And we don’t know why people left. It could have been a question of political factioning, warfare, drought, or disease – we just don’t know. “

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