Use of Ground Penetrating Radar to map subsurface features at Lapa do Santo archaeological site (Brazil)

In this article we present some results of Ground Penetrating Radar (GPR) studies carried out at Lapa do Santo archaeological site. This cave is within Lagoa Santa karstic region, Minas Gerais State, Brazil. In the first field work, 44 GPR profiles were acquired with 100 MHz, 200 MHz, and 400 MHz shielded antennas focusing on three mains objectives: (i) to characterize stratigraphic layer; (ii) to identify geological and archaeological anomalies, and (iii) to identify potential areas aiming at assisting archaeologists in an excavation program. GPR results indicated anomalous hyperbolic reflections, and areas with high sub-horizontal reflection amplitude suggesting archaeological and geological potential targets, respectively. These results were encouraging, and then they were used to guide excavations at this site. Excavation of test units (meter by meter) allowed identifying an anthropogenic feature, e.g., a fire hearth structure, and natural features, such as speleothems and top of bedrock. Results also indicated the importance of GPR survey as a tool for orienting archaeological researches, increasing the probability of finding archaeological interest targets in an excavation program an area of environmental protection.