Investigating reworking of proglacial sediments using GPR: Skeioararjokull

• Main Authors: Woodward, John, Burke, Matthew, Tinsley, R., Russell, Andrew J.
• Format: Conference Object
• Language: English
• Published: University of Birmingham 2008
• Subjects: F600 Geology; F800 Physical and Terrestrial Geographical and Environmental Sciences; Iceland
• Online Access: https://nrl.northumbria.ac.uk/id/eprint/542/

We present ground-penetrating radar data from Skeioararjokull, Iceland illustrating paraglacial reworking of glacio-fluvial sediments. In the spring and summer of 2006 and 2007 a series of GPR surveys were conducted using a pulseEKKO Pro 1100 with 200 MHz antennae. The sediments were deposited within a supraglacial ice-walled canyon during a flood event caused by drainage of a subglacial lake in 1996. The common offset surveys imaged the sediments to a depth of 12 m above a zone of strong attenuation, believed to represent buried ice. Example profiles are described from two locations on the canyon fill. Grid 1 was collected close to a ~ 10 m high sediment face, where a number of prominent surface scarps have developed in the sediment. Grid 2 was collected near the centre of the canyon fill where subsidence is occurring in the outwash surface. GPR profiles from Grid 1 show discontinuous and offset reflections beneath the surface scarps, due to rotational slumping. GPR profiles from Grid 2 reveal normal and reverse faulting, reflection-free zones as well as warping of prominent reflections. The reworking is thought to be due to melting and movement of frozen sediment and buried ice at or beneath the water table. Future repeat surveys of these grids will allow monitoring of the processes of landscape readjustment in proglacial environments.