Abstract

Long-term field studies of contemporary pingo growth, collapse, and rampart formation along the western Arctic coast of Canada provide criteria that may be helpful in the identification of pingo ramparts in nonpermafrost environments. Such criteria include the volume of the ramparts, which should approximate that of the enclosed depressions from which the rampart materials were derived; peripheral deposits associated with mass wasting, streamflow, and debris flow; casts of dilation crack ice trending across the ramparts; and high-angle peripheral normal faults. The conventional method of correlating the present mean annual air temperature with the present pingo distribution to establish warm-side limiting temperatures for paleoclimatic reconstruction is unsound, because most pingos in North America and the Soviet Union commenced growth hundreds to thousands of years ago under mean annual air temperatures that may have differed greatly from those of the present. Some other factors to be considered in paleoclimatic reconstruction are the thermal offset; site availability; the differing requirements for the growth of large pingos as compared with small pingos; and the long time required for pingos to grow to full size.

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