Chahokia Mystery

For a couple of hundred years, Cahokia was the place to be in what is now the US state of Illinois. The bustling, vibrant city was at one time home to some 15,000 people, but by the end of the 14th century it was deserted – and researchers still aren't sure why.

A new study has been able to rule out one previous idea – that deforestation and overuse of the land around Cahokia caused excessive erosion and local flooding in the area, making it less inhabitable for Native Americans.

Through an analysis of sediment cores gathered near earthen mounds in the Cahokia Mounds State Historic Site, researchers have established that the ground remained stable from Cahokia's heyday until the mid-1800s and industrial development. In other words, there was no environmental disaster.

"There's a really common narrative about land use practices that lead to erosion and sedimentation and contribute to all of these environmental consequences," says geoarchaeologist Caitlin Rankin from the University of Illinois at Urbana-Champaign. "When we actually revisit this, we're not seeing evidence of the flooding."

The mounds that the excavation site was next to are in low-lying areas and close to a creek – a prime position for any local flooding that would have happened. Yet there were no signs of sediment left behind by floods in the layers of earth.  READ MORE

https://www.sciencealert.com/the-mystery-deepens-over-why-the-lost-city-of-cahokia-was-abandoned