Unveiling hidden prehistoric structure via high-resolution GPR survey at Hierakonpolis, Aswan, Egypt

Hierakonpolis was a major population and political center in Upper Egypt during the Predynastic era (c. 3800-3100 BC). Its ancient remains are preserved mainly as negative archeological features (i.e., structural cuts that disrupt the natural soil), such as postholes and foundation trenches for buildings of wood. One of these constructions is a large palisade wall, of which over 50 m of its length has been uncovered by archaeologists. To trace the buried continuation of this structure without excavation, researchers conducted a ground-penetrating radar (GPR) survey using a high-frequency (900 MHz) antenna. Despite subtle physical contrasts between the remains and the soil, the arid conditions allowed the GPR to detect the foundation trench as a lateral discontinuity within the Nile silt layer that extends across the entire study area. GPR scans revealed that the wall continues westward along the same trajectory as its excavated segments for an additional 18 m before the signal terminated. Analysis of GPR facies suggests that repeated flooding from an ancient Nile channel compromised the site's stability, likely resulting in the destruction of the wall in the northwestern sector. Archaeological findings indicate the wall demarcated a large ceremonial and administrative complex, while the survey results also suggest it had a broader functional role as a defensive barrier against Nile floodwaters and other natural threats.