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Figure 7.18. Photo showing a deformed massive ground ice body exposed near Nicholson Point,
Pleistocene Mackenzie Delta, Canada. Note also the large epigenetic ice wedge in the silty diamicton
above the massive ice.
Figure 7.19. A classifi cation of massive ground ice proposed by J. R. Mackay at a Geological
Survey of Canada seminar in Ottawa in 1989.
Kaplanskaya and Tarnogradsky, 1986) and the Western Canadian Arctic (e.g. French and
Harry, 1988, 1990; Mackay, 1971, 1973b; Mackay and Dallimore, 1992; Murton et al.,
2005). Many show glaciotectonic structures or deformations (see Figure 7.18; Lokrantz
et al., 2003; Murton et al., 2004). Others exhibit anticlinal structures apparently related
to diapiric uplift and pressure release following removal of overlying material (Mackay
and Dallimore, 1992).
The two main explanations advanced for the origin of these icy bodies are: (1) segre-
gated ice which, with increasing importance of water-injection processes, grades into
intrusive ice, and (2) buried glacier ice, without a clear distinction being made between
glacier ice derived from snow and sub-glacier regelation ice. A more comprehensive clas-
sifi cation of massive ground ice bodies, based on these two different origins, is given in
Figure 7.19. Massive segregated ice bodies are regarded as “intra-sedimental.”
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