One of the biggest puzzles in North American archaeology is how the relatively small bands of hunter-gatherers living at that time could have built monumental architecture on this scale without food surpluses provided by farming or the centralized leadership of a king or chief.
One theory is that many small groups of hunter-gatherers came together on a seasonal basis year after year for generations to slowly construct this complex of parallel embankments and mounds.
However, the results of new excavations into the largest of Poverty Point’s mounds refute this theory.
May have to go grab the paper that’s referenced and read it to see how they determined the building time. But it’s another indication that hunter-gatherers as a group need to be reassessed.