A few millennia later, there is still much to learn about remarkably advanced early civilizations, particularly the indigenous peoples of North America.
A new study sheds light on the “sophisticated” engineering work by early Native Americans at the World Heritage Site at Poverty Point in northern Louisiana. Though they were originally presumed to be a community of hunter-gatherers, researchers at Washington University in St. Louis reveal new details about massive earthen structures built to last more than 3,400 years — a huge undertaking.
The site features a 72-foot-tall dirt mound surrounded by concentric half-circle ridges (like ripples on the surface of water) made of 2 million cubic yards of soil.
The supersized monument was completed in months, or potentially weeks, without modern tools, work animals or even wheeled carts for hauling material.
“We as a research community — and population as a whole — have undervalued native people and their ability to do this work and to do it quickly in the ways they did,” said Tristram Kidder, the study’s lead author, in a statement for the university.
Whereas far more modern structures “fail with amazing regularity,” the dirt-based structures at Poverty Point “have held together … with no failure or major erosion.”
“They really were incredible engineers with very sophisticated technical knowledge,” Kidder added of the study, published in Southeastern Archaeology on Wednesday.
Their new findings suggest the work was completed at breakneck speed. Archaeologists found no evidence of a pause between phases of work, which would be indicated by regular weathering of the structure due to rain and climate.
“Between the speed of the excavation and construction, and the quantity of earth being moved, these data show us native people coming to the site and working in concert. This in and of itself is remarkable because hunter-gatherers aren’t supposed to be able to do these activities,” Kidder said.
Researchers believe the area was an important religious gathering place for Native Americans, but abandoned some 2,000 years ago — presumably due to regular floods in the Mississippi River Valley, Kidder said.
Indeed, the fact that the structures still stand is a testament to their fortification — despite thousands of years of heavy rain typical of the Gulf region, as well as increasingly prevalent and powerful hurricanes and flooding. Kidder credits the Native American builders’ complementary understanding of geology and earth sciences.
“Similar to the Roman concrete or rammed earth in China, Native Americans discovered sophisticated ways of mixing different types of materials to make them virtually indestructible, despite not being compacted,” Kidder explained.
He added, “There’s some magic there that our modern engineers have not been able to figure out yet.”