GPR Mapping of a Buried Paleolithic Landscape Near Kathu, South Africa

Abstract:

he Bestwood site located near Kathu, South Africa is a 30 Ha sand-filled valley where tens of thousands of artifacts (hand axes and stone tools) dating from 700Kya to 1Mya mark a previously inhabited Stone Age site. By running close to 10 km of GPR lines and two 20mX20m grids with a 200 MHz antenna we were effectively able to sample the subsurface of the area and thus recreate the paleolandscape. Raw radargrams were viewed and processed through the MATLAB and GPR-SLICE programs. Both the raw and processed radargrams showed a distinct boundary as the GPR was moved from gravel hill conditions to sandy valley conditions. This boundary was interpreted to be an interface in the subsurface between sand on top and gravel layers below. A sinuous, meandering depression within that boundary that progressed down valley was interpreted as a paleochannel incised into the local gravels. Within the 20mx20m grids two 1mx1m test pits were dug on the assumed banks of the paleochannel. The pits served both to ground truth the inferred transition from sand to gravel and to help define a precise velocity of radar propagation for the sand layer. Our results aid archaeologists in understanding the interactions of early humans with the local landscape.