Looking through drumlins: testing the application of ground-penetrating radar

Ground-penetrating radar (GPR) is becoming a commonly applied technique in
geomorphology. However, its use in the study of subglacial bedforms has yet to be fully explored
and exploited. This paper presents the results of a GPR feasibility study conducted on a drumlinized
terrain in Cumbria, UK, where five drumlins were investigated using multiple radar antenna
frequencies. The site was selected for the presence of nearby bedrock outcrops, suggesting a shallow
drumlinized diamict–bedrock contact and a permeable lithology. Despite the clayey sediment and
unfavourable weather conditions, a considerable penetration depth of �12m was achieved when using
a 50MHz antenna, with a separation of 1 m, trace spacing of 1m and 128-fold vertical stack. Results
indicate that the drumlinized diamict is in direct erosional contact with the bedrock. While the internal
drumlin geometry is generally chaotic on the stoss side, evidence of layering dipping downflow at an
angle greater than the drumlin surface profile was found on the lee side. The inter-drumlin areas
comprise �4m of infill sediment that masks part of the original drumlin profile. Overall, this study
indicates that GPR can be deployed successfully in the study of glacial bedform sedimentary
architecture.