Electrical resistivity of ice from the Antarctic Peninsula, Antarctica
Georesistivity soundings have been carried out at four sites in the Antarctic Peninsula. The objective of the work was to investigate the electrical behaviour of ice from an area where substantial melting occurs in summer and from contrasting thermal regimes. Electrical measurements made at three sites along a flow line within George VI Ice Shelf reveal that: (a)
the resistivity of deep ice is similar to that of other Antarctic ice shelves,
(b)
the resistivity of the ice-shelf surface, which is affected by the percolation and refreezing of melt water, is similar to that of deep ice and hence the ice is polar in character.
A compilation of published resistivities of deep ice from polar regions shows that the range of resistivities is very narrow (0.4 –2.0) x 105 Ω m between –2 and – 29°C, irrespective of the physical setting and history of the ice. Typically, resistivity is within a factor of two of 80 kΩ m at –20° C with an activation energy of 0.22 eV. In contrast, the resistivity of surface ice at Wormald Ice Piedmont, where the ice is at 0°C throughout, is two orders of magnitude higher and falls at the lower end of the range of resistivities for temperate ice.