A geoarchaeological perspective on the challenges and trajectories of Mississippi Delta communities

Recent geochronology of the Mississippi Delta of coastal Louisiana, USA, provides a high-resolution record of land growth that facilitates the study of ancient settlement patterns in relation to delta evolution. We use stratigraphy and optically stimulated luminescence (OSL) dating to show that two Late Holocene earthen mounds were constructed several hundred years after the land emerged from open water. This multi-century pause allowed natural processes of overbank and crevasse splay deposition to elevate the land surface, reduce flood risk, and foster desirable environmental conditions prior to human occupation. These results are applied to obtain new age constraints for a large number of at-risk or lost archaeological sites with little-to-no absolute chronology. We use our findings to comment on prehistoric, contemporary, and future human-landscape interactions in the Mississippi Delta and other deltaic environments.