Karst features interpretation using ground-penetrating radar: a case study from the Sierra de Atapuerca, Spain

Abstract

We used ground-penetrating radar (GPR) to identify a variety of karstic features in the archaeo-paleontological sites of the Sierra the Atapuerca (Burgos, Spain). The aim of this study was to discover the structure of the caves exposed in the 19th century by a railroad trench, specifically their bottom part, which remains covered under the railroad current surface. For this purpose, three GPR grids were made in the Trinchera area, next to the sites of the Sima del Elefante, the Galería Complex and the Gran Dolina. The analysis of both the radar wave signatures and the radar amplitude reflections, together with the existing data on the caves, allowed for the definition of the location and geometry of different karstic features, including air-filled caves, sediment-filled caves and bedrock structures. Two mechanical boreholes drilled next to the sites also added the information on the stratigraphy of the bottom part of the caves and helped with the interpretations of the GPR survey. We could distinguish between the intact geological features and the areas that were altered by the railroad construction and the later quarrying activity.