3-D mapping of Svalbard glacier caves
Top image: A cut-and-closure canyon incised its way to the bed to form the subglacial conduit system at Rieperbreen. Photo: Jason Gulley.
Glaciers’ inner hydrological systems remain largely unknown, so speleological work delivers precious information and helps creating 3-dimensional maps of glacier englacial and subglacial drainage system. Jason Gulley reports on his work in glacier caves in Svalbard.
17 November 2009
Text: Jason Gulley, PhD student at University of Florida and UNIS
This research project is helping fill a significant gap in knowledge by using caving techniques to make detailed, three-dimensional maps of glacier hydrological systems and simultaneously conducting Ground Penetrating Radar (GPR) surveys over the mapped conduit systems.
The speleological maps provide key information about passage morphology that helps interpret the geophysical data.
By ‘calibrating’ the GPR reflectors to known conduit morphologies, this study will help interpret GPR data from glaciers where conduit systems are not directly accessible (such as deep portions of the Greenland Ice Sheet).
Fieldwork in Hornsund and Bolterdalen
Fieldwork for this project, conducted in close collaboration with scientists at the Polish Polar Station in Hornsund, was carried out this autumn on Hansbreen and Werenskioldbreen in Hornsund and at Rieperbreen (in Bolterdalen, near Longyearbyen).
During fieldwork at Hornsund ~9 englacial conduits were investigated. Most englacial conduits were simple moulins that became too constricted to continue after reaching depths of about 30 meters.
Two englacial conduits led to extensive englacial and subglacial conduit systems. Both conduit entrances were located in ice marginal lake basins at glacier confluences. The englacial conduits are interpreted to have formed by hydrofracture in zones of longitudinal extension.
Following a short reconnaissance trip to two conduits on Werenskioldbreen, fieldwork was shifted to study an extensive conduit system beneath Rieperbreen (Bolterdalen) in mid-October. Nine potential conduit entrances were investigated on Riperbreen. The conduit system is interpreted to have formed as a cut-and-closure canyon that has migrated up the glacier. More than 500 meters of englacial and subglacial conduit were mapped and the conduits continued at the furthest point of exploration.
It is hoped to finish surveying the conduit system and conduct GPR surveys in April 2010. Because Rieperbreen has the only subglacial conduit system that has been mapped entirely from recharge point to discharge point, it is an ideal location to groundtruth the interpretation of dye trace breakthrough curves, geophysical imaging techniques and to validate models of the subglacial hydrology.
Detailed analysis of data collected from this project will begin in January 2010.