Georadar facies and glaciotectonic structures in ice marginal deposits, northwest Zealand, Denmark

Ground penetrating radar (GPR) measurements have been carried out on an outwash plain and in the rim of an adjacent ice-push ridge in northwest Zealand, Denmark. The radar profiles are differentiated into radar facies with distinct reflection characteristics. The lithology and depositional environment of the radar facies is interpreted by correlating information from profiles in gravel pits, geological maps and bore hole data. The GPR profiles reveal sedimentary structures and glaciotectonic deformation structures. Several thrust planes and folds are interpreted from the GPR data. The deformation style of the tectonised glaciofluvial sediments is a pro-glacial thin-skinned thrust complex, with associated folding. The deformations have resulted in the present ridge morphology seen in the rim of the ice-push ridge. On top of the deformed sediments and in front of them penecontemporaneous and post tectonic sediments are deposited, smoothing the ridge relief created by the thin-skinned thrust complex.