Prehistoric Temple on Mississippi Delta Abandoned Due to Ecological Changes

The Grand Caillou Mound in the Mississippi River Delta may have been abandoned due to environmental stress.

 Credit: Jayur Mehta

“Dating an abandonment event can be challenging,” said Chamberlain. “Within our suite of radiocarbon ages at Grand Caillou, there were none younger than 600 years. This suggests that people may have moved on to a new site at that time.”

“The abandonment of the river channel would have caused a number of changes to the ecology and landscape at the Grand Caillou mound,” added Mehta. “This may be an early example of people responding to changes in Mississippi Delta landscape by relocating.”

The researchers also found that the location and architecture of the mound–it stands 20 feet tall–indicated a great degree of environmental and engineering expertise among the people who built it.

“This region is naturally high elevation, and offered access to waterways for transportation and hunting,” said Mehta.

Geologic coring showed that the mound was built in alternating layers of sand and mud. While sand is a common deposit near the mound, mud must have been imported from farther away.

“This demonstrates a high level of geotechnical knowledge by native people, and a big group effort in mound construction,” said Chamberlain. “Waterlogged mud is heavy, and all this material was moved by hand.”

The study also used artifacts recovered from the mound to identify the culture of the people who lived there. This helped to connect the Grand Caillou inhabitants with mound-building groups farther upstream in the Mississippi River Valley and along the Gulf Coast.

“Research such as this is especially important in light of recent published work showing that net land loss will continue in the Mississippi Delta,” said Chamberlain.

“Archaeological sites are a non-renewable resource,” added Mehta. “With the loss of coastal land, we also risk losing these valuable records of how prehistoric people lived in the Mississippi Delta. It is critical to recover and document archaeological records before they slip beneath the sea.”

Contacts and sources:
Liz Entman
Vanderbilt University