GEOARCHAEOLOGY OF MOUND A AT POVERTY POINT

Mound A at Poverty Point is the second largest earthwork in the United States, with an estimated volume of ca. 238,500 m2, and is remarkable, in part, because it was built by people with a hunter-gatherer subsistence economy. Mound A has been described as an effigy of a bird flying to the west. Although physically central to the site plan, and clearly important to the pre-Hispanic population, Mound A has received limited archaeological attention. Geoarchaeological investigations between 2001 and 2005 included the excavation of 72 cores and a 10 meter deep trench into the flank of the mound. Field and laboratory investigations include standardized core descriptions and depth measurements, particle-size analysis, loss-on-ignition analysis, and microartifact studies. Findings from these studies reveal the earthwork was built as two separate mounds. The western part of the mound was erected over a long period of time, and pre-dates 2000 cal B.C. The eastern platform, on the other hand, was built after 1450 cal B.C., and was erected in a remarkably short span, probably in less than three months. Results of our work require a reconsideration of the place of Mound A in Poverty Point's history and have implications for understanding the site's population dynamics and the nature of social complexity among hunter-gatherer populations. Mound A was not built as an effigy. The original construction was the result of efforts over a considerable period of time, suggesting a relatively small population, probably returning to the site to add to the mound. The rapid construction of the platform indicates the population had increased significantly and the social structure of the people living at Poverty Point was sufficient to plan the construction, mobilize and direct labor, and provide for subsistence needs. We estimate the site had a population of over 1500 persons at its height, which makes it one of the largest sedentary hunter-gatherer communities documented.