Abstract
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 12 m was achieved when using a 50 MHz antenna, with a separation of 1 m, trace spacing of 1 m 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 4 m 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.
drumlinized diamict–bedrock contact and a permeable lithology. Despite the clayey sediment and unfavourable weather conditions, a considerable penetration depth of 12 m was achieved when using a 50 MHz antenna, with a separation of 1 m, trace spacing of 1 m 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 4 m 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.
| Original language | English |
|---|---|
| Pages (from-to) | 1126-1134 |
| Number of pages | 9 |
| Journal | Journal of Glaciology |
| Volume | 60 |
| Issue number | 224 |
| DOIs | |
| Publication status | Published - 2014 |
Bibliographical note
ACKNOWLEDGEMENTSWe thank the editor, Bernd Kulessa, for his review and support, and John Hiemstra and an anonymous reviewer for helpful comments and suggestions. This work was supported by an equipment loan from the UK Natural Environment Research Council (NERC) Geophysical Equipment Facility (Loan 990) and a University of Aberdeen, College of Physical Sciences’ Research and Teaching Enhancement Fund. All authors are indebted to the NERC Geophysical Equipment Facility staff for training in the use of the antennas and GPS. J.C.E. thanks the Denisons for funding
his PhD. We also thank Wharton Hall and Shaw Paddock farms for access to the field sites.
Keywords
- drumlins
- geomorphology
- glaciological instruments and methods
- ground-penetrating radar