Poverty Point Samples
© Photo courtesy of Rinita Dalan
Examining soil core samples at Poverty Point World Heritage Site are, from left, Thurman Allen, a soil scientist retired from the Natural Resources Conservation Service; Mark Brink, Poverty Point WHS manager; Rinita Dalan, Ph.D., of Minnesota State University Moorhead; and Diana Greenlee, Ph.D., Poverty Point WHS station archaeologist, and ULM adjunct professor.
These earthworks, together with a buried, mound-like feature with unique soil properties unlike any of the known earthworks at the site, demonstrate that the Plaza at Poverty Point has a more elaborate construction history than we knew.

Diana Greenlee, Ph.D.
Poverty Point World Heritage Site is slowly revealing her secrets.

Diana Greenlee, Ph.D., station archaeologist at the ancient monumental earthworks and adjunct professor at the University of Louisiana Monroe School of Sciences, said recent archaeological research shows the site is "much more complex than previously realized."

The joint project by ULM and Minnesota State University Moorhead (MSUM ) was funded with a 2019 Preservation Technology and Training Grant from the U.S. Dept. of the Interior, National Park Service.

Greenlee, Rinita Dalan, Ph.D., of MSUM, and their colleagues focused on Poverty Point's central Plaza. This 43-acre area was created thousands of years ago by removing the original topsoil and then adding fill dirt to build a raised, near-level surface. To look at the Plaza today, one would not suspect what is hidden below.

Parts of the Plaza were surveyed using a sophisticated ground penetrating radar developed in Norway and used extensively by the Norwegian University of Science and Technology. Arne Anderson Stamnes, Ph.D., of the university's Terrestrial, Marine, and Aerial Remote sensing for archaeology research group, operated the GPR.

Nearly 2,000 reflectors, which are objects or soil disturbances that reflect the radar signals, were identified. These results were compared to other geophysical surveys.

Then, several targets were tested using a combination of soil coring, analyses of soil samples, and sieving for artifacts, and by lowering a geophysical sensor down the cored holes.

Poverty Point World Heritage Site
© Photo courtesy of Rinita Dalan
Diana Greenlee, Ph.D., ULM adjunct professor and station archaeologist at Poverty Point World Heritage Site (driving), with passenger Arne Anderson Stamnes, Ph.D., of the Norwegian University of Science and Technology, conduct a multi-channel ground penetrating radar survey at Poverty Point World Heritage Site.
"Although more work remains to be done, the results show that the Plaza contains a number of distinct earthworks. A subtle high spot in the Plaza, the West Plaza Rise, was not a natural rise, but a purposely elevated feature within the Plaza fill," Greenlee said.

An underground ridge, formed by removing more of the original soil from both sides, stretches across the Plaza from the West Plaza Rise to Mound C.

"These earthworks, together with a buried, mound-like feature with unique soil properties unlike any of the known earthworks at the site, demonstrate that the Plaza at Poverty Point has a more elaborate construction history than we knew," Greenlee said.

Site plan of Poverty Point
© Maximilian Dörrbecker (Chumwa) – CC BY-SA 2.5
Site plan of Poverty Point.
Participating in the research with Greenlee, Dalan, and Stamnes were Thurman Allen, a soil scientist retired from the Natural Resources Conservation Service; Rachel Stout Evans, a soil scientist with the Natural Resources Conservation Service; Michael Hargrave, Ph.D., an archaeologist retired from the Engineer Research and Development Center; and Berle Clay, Ph.D., an archaeologist retired from Cultural Resource Analysts, Inc.

Poverty Point WHS, located in West Carroll Parish in northeast Louisiana, is a complex of earthen mounds and C-shaped earthen ridges built some 3,700 to 3,100 years ago. It is one of only four archaeological sites in the United States that has earned the WHS designation.