A 3D GPR Time Slice Analysis of Paleo-reconstructions at Mound A, Ocmulgee National Monument

Prehistoric societies from around the world constructed monumental mounded architecture or earthen pyramids for a variety of functions including the foundation for temples, leader’s residences, community stages, or cemeteries. Flat-topped earthen mounds often have complicated histories where the function, size, orientation, and summit architecture varied throughout time. This paper presents the results from a 500 MHz GPR survey conducted on the summit of Mound A, the largest prehistoric Native American mound at Ocmulgee National Monument located in central Georgia. Our study indicates that performing time-slice analyses of flat-topped mounds can effectively map successive construction stages and maintain sufficient resolution to identify summit architecture on earlier mound use episodes. The authors recorded four mound construction stages, the western expansion of the mound, and the shifting location and shape of summit architecture. Changes in summit architecture and mound size inform us of the shifting political landscape at Ocmulgee between approximately AD 900-1200.This study also resolved a discrepancy regarding the location of early archaeological excavation units from the 1930s. This may help archaeologists accurately provenience artifacts during future investigations.