A number of competing hypotheses, including hydroclimatic variations, environmental degradation and disturbance, and sociopolitical disintegration, have emerged to explain the dissolution of Cahokia, the largest prehistoric population center in the United States. Because it is likely that Cahokia’s decline was precipitated by multiple factors, some environmental and some societal, a robust understanding of this phenomenon will require multiple lines of evidence along with a refined chronology. Here, we use fecal stanol data from Horseshoe Lake, Illinois, as a population proxy for Cahokia and the broader Horseshoe Lake watershed. We directly compare the fecal stanol data with oxygen stable-isotope and paleoenvironmental data from the same sediment cores to evaluate the role of flooding, drought, and environmental degradation in Cahokia’s demographic decline and sociopolitical reorganization. We find that Mississippi River flooding and warm season droughts detrimental to agriculture occurred circa (ca.) 1150 CE and possibly generated significant stress for Cahokia’s inhabitants. Our findings implicate climate change during the Medieval Climatic Anomaly to Little Ice Age transition as an important component of population and sociopolitical transformations at Cahokia, and demonstrate how climate transitions can simultaneously influence multiple environmental processes to produce significant challenges to society.
|Number of pages
|Proceedings of the National Academy of Sciences of the United States of America
|Published - 2019
Bibliographical noteFunding Information:
ACKNOWLEDGMENTS. We thank Sabrina Brown, Ian Bull, Jase Hixson, Hannah Hixson, Lindsey Jean-Shaw, Joe Mohan, Mo Nonu, Jeffery Stone, and Amanda White for their contributions. We thank the editor who forwarded this paper for review and two anonymous reviewers for their comments on an earlier version of this manuscript. This work was supported by funding from the Geological Society of America and California State University, Long Beach (CSULB). The Institute for Integrated Research on Materials, Environment, and Society Laboratory at CSULB provided laboratory access, material support, and project consultation.
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- Fecal stanols
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