PERMAFROST SCIENCE IN THE CANADIAN ARCTIC
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My arctic research began as a doctoral candidate at Queen's University under the supervision of Dr. Robert Gilbert. While at Queen's I examined the physical, thermal, and geochemical characteristics of ground ice near municipal water storage facilities on Baffin Island in arctic Canada. My publications on this work use ice wedge characteristics to reconstruct Holocene environmental change as well as to evaluate the importance of subsurface cavities in destabilizing ice-rich permafrost. Also, I have recently published two papers in the 7th international permafrost conference proceedings. These papers use cryostratigraphic and stable isotopic data to test hypotheses of ground ice origin, as well as analyzing ground temperature data to evaluate the extent to which reservoir construction has modified ground thermal regimes.

Abstracts for these papers are given below. 
Reconstruction of Holocene 
Periglacial Environments in the Pangnirtung Area Based on Ice Wedge Characteristics
Ice wedges exposed during the construction of a reservoir near Pangirtung, N.W.T. were examined during the summer of 1986. They are contained within raised deltaic sands and gravels and are overlying sandy diamict located at or slightly above the local marine limit. The ice wedges, which average 0.75 m in widtha nd more than 1.0 m inheight, are thought to have formed following emergence approximately 8700 years B.P. Near vertical sides on many of the ice wedges, together with secondary growth veins which terminate part way down the sides of the ice wedgs, imply lateral and vertical ice growth within aggrading permafrost. Periods of ice wedge decay may be inferred from thaw unconformities observed over some ice wedges.

Reference: Hyatt, J. A. 1990. In: Permafrost - Canada Proceedings of the Fifth Canadian Peramfrost Conference, National Research Council Canada, Quebec City, pp. 17-21

Cavity Development in Ice-rich Permafrost, Pangnirtung, Baffin Island, Northwest Territories

Cavity development in ice-rich permafrost at Pangirtung followed a large rainstorm and runoff event in 1984. The cavities evolved along permeable zones in sediments containing segregated ice lenss. Cavities promoted subsurface flow and incremental collapse of the gournd surface. Once formed, cavities remained reelatively stable where they were free to drain, and where the enclosing ground remained frozen and rigid support was provided. Some cavities closed by infilling with sediment or freezing water, or by deformation of the surrounding frozen ground. Other cavities were enlarged by thermo-erosional piping, a process involving both thermal and mechanical erosion of frozen ground together with sufficiently rapid throughflow to prefent refreezing.

A classification of cavities in permafrost permits qualitative appraisal of their stability with respect to the depth of zero annual temperature change and the degree of natural arching support. Assessment based on elastic plate theory indicates that seasonal temperature changes are important factors in destabilizing near-surface cavities.

Reference: Hyatt, J. A. 1992. Permafrost and Periglacial Processes. Vol. 3: 293-313. 
The origin of lake-bed ground ice at Water Supply Lake, Pond Inlet, Nunavut, Canada.
Cryostratigraphic and hydrochemical characteristics are described for in situ lake-bed ground ice exposed by excavations in a drained lake during construction of an earthwork dike at Water Supply Lake on northeastern Baffin Island. Ground ice occurs as ice lenses 5 mm to 0.5 m thick having cryostructures indicative of a segregation origin. The ice is ionically enriched and isotopically lighter than overlying lake water. These data, together with local changes in surficial geology, and dated wood fragments recovered from the site, are used to infer the origin of lake-bed ground ice.  This ice is thought to be relic having formed 29 ka BP when the area last emerged from beneath mid-Wisconsinan Eclipse glacier ice. Permafrost aggradation and the growth of segregated ice lenses incorporated isotopically light meltwater that flooded the area during a still-stand of retreating Eclipse ice. Modern dike construction has raised water levels, submerging and thermally degrading the ground ice.

Reference: Hyatt, J. A. 1998. In: A. G. Lewkowicz and Allard, M. (editors), Proceedings, Seventh International Conference on Permafrost, Yellowknife, 23-27 June 1998, Universite Laval, Collection Nordicana no. 57, p. 487-494.