The environmental impact of a pre-Columbian city based on geochemical insights from lake sediment cores recovered near Cahokia

A distinct sediment layer in Horseshoe Lake, formed between AD 1150 and 1220, reveals the environmental impact of Cahokia's expansion. This gray, fine-grained layer, characterized by low carbonate δ13C, elevated metal concentrations (lead, copper, potassium, aluminum), and increased organic matter δ15N, correlates with archaeological evidence of heightened agricultural activity, mound construction, and population growth. The study suggests that human activities intensified soil erosion, altering sediment sources and nutrient cycling in the watershed. Geochemical analysis of a 1500-year-old lake core provides a novel, multi-proxy record of pre-Columbian urbanization's ecological footprint.

Pompeani, D. P., Hillman, A. L., Finkenbinder, M. S., Bain, D. J., Correa-Metrio, A., Pompeani, K. M., & Abbott, M. B. (2018). The environmental impact of a pre-Columbian city based on geochemical insights from lake sediment cores recovered near Cahokia. Quaternary Research, 91(2), 714–728. https://doi.org/10.1017/qua.2018.141