WISSARD Hot Water Drill System design and overall description

The first scientific use of the WISSARD hot water drill system provided clean access through ~800 meters of ice into Subglacial Lake Whillans (SLW) in late January 2013. This is described in a paper by Tulaczyk and other (2014) published in the Annals of Glaciology v. 55(65), which includes the deployment of an array of scientific tools through the SLW borehole: a downhole camera, a conductivity-temperature-depth (CTD) probe, a Niskin water sampler, an in situ filtration unit, three different sediment corers, a geothermal probe and a geophysical sensor string.

Observations confirm the existence of a subglacial water reservoir whose presence was previously inferred from satellite altimetry and surface geophysics. Subglacial water is about two orders of magnitude less saline than sea water (0.37-0.41 psu vs 35 psu) and two orders of magnitude more saline than pure drill meltwater (<0.002 psu). It reaches a minimum temperature of -0.558C, consistent with depression of the freezing point by 7.019MPa of water pressure.

Subglacial water was turbid and remained turbid following filtration through 0.45 mm filters. The recovered sediment cores, which sampled down to 0.8 m below the lake bottom, contained a macroscopically structureless diamicton with shear strength between 2 and 6kPa.